Phaser® 8400/8500/8550 Color

Printer
Service Manual

Warning
The following servicing instructions are for use by qualified service
personnel only. To avoid personal injury, do not perform any servicing other
than that contained in the operating instructions, unless you are qualified to
do so.

December, 2005
721P58550
Copyright © 2005 Xerox Corporation. All Rights Reserved. Unpublished rights reserved under the
copyright laws of the United States. Contents of this publication may not be reproduced in any form
without permission of Xerox Corporation.
Copyright protection claimed includes all forms of matters of copyrightable materials and information now
allowed by statutory or judicial law or hereinafter granted, including without limitation, material generated
from the software programs which are displayed on the screen such as styles, templates, icons, screen
displays, looks, etc.

XEROX®, The Document Company®, the digital X®, CentreWare®, FinePoint™, infoSMART®, Made For
Each Other®, PagePack™, Phaser®, PhaserSMART®, TekColor™, and Walk-Up™ are trademarks of Xerox
Corporation in the United States and/or other countries.

Acrobat®, Adobe® Reader®, Adobe Type Manager®, ATM™, Illustrator®, PageMaker®, Photoshop®,
PostScript®, Adobe Brilliant® Screens, Adobe Garamond®, Adobe Jenson™, Birch®, Carta®,
IntelliSelect®, Mythos®, Quake®, and Tekton® are trademarks of Adobe Systems Incorporated in the
United States and/or other countries.

Apple®, AppleTalk®, EtherTalk®, LaserWriter®, LocalTalk®, Macintosh®, Mac OS®, TrueType®, Apple
Chancery®, Chicago®, Geneva®, Monaco®, New York® , and QuickDraw® are trademarks of Apple
Computer, Inc. in the United States and/or other countries.

HP-GL®, HP-UX®, and PCL®are trademarks of Hewlett-Packard Corporation in the United States and/or
other countries.

IBM® and AIX® are trademarks of International Business Machines Corporation in the United States and/
or other countries.

Windows®, Windows NT®, Windows Server™, and Wingdings® are trademarks of Microsoft Corporation
in the United States and/or other countries.

Novell®, NetWare®, NDPS®, NDS®, Novell Directory Services® , IPX™, and Novell Distributed Print
Services™are trademarks of Novell, Incorporated in the United States and/or other countries.

SunSM, Sun Microsystems™, and Solaris® are trademarks of Sun Microsystems, Incorporated in the United
States and/or other countries.

SWOP® is a trademark of SWOP, Inc.

UNIX® is a trademark in the United States and other countries, licensed exclusively through X/Open
Company Limited.

As an ENERGY STAR® partner, Xerox Corporation has determined that this product with an ES Option
meets the ENERGY STAR guidelines for energy efficiency. The ENERGY STAR name and logo are registered
U.S. marks.

PANTONE® Colors generated may not match PANTONE-identified standards. Consult current PANTONE
Publications for accurate color. PANTONE® and other Pantone, Inc. trademarks are the property of
Pantone, Inc. © Pantone, Inc., 2000.
User Safety Summary

Terms in Manual
Caution
Conditions that can result in damage to the product.

Warning
Conditions that can result in personal injury or loss of life.

Power source: For 110 VAC printers, do not apply more than 130 volts RMS
between the supply conductors or between either supply conductor and ground. Use
only the specified power cord and connector. For 220 VAC printers, do not apply
more than 250 volts RMS between the supply conductors or between either supply
conductor and ground. Use only the specified power cord and connector. Refer to a
qualified service technician for changes to the cord or connector.
Operation of product: Avoid electric shock by contacting a qualified service
technician to replace fuses inside the product. Do not operate without the covers and
panels properly installed. Do not operate in an atmosphere of explosive gases.

Warning
Turning the power off using the On/Off switch does not de-energize the
printer. You must remove the power cord to disconnect the printer from the
mains. Keep the power cord accessible for removal in case of an emergency.

Safety instructions: Read all installation instructions carefully before you plug the
product into a power source.

Terms on Product

Warning
A personal injury hazard exists that may not be apparent. For example, a
panel may cover the hazardous area. Also applies to a hazard to property
including the product itself.

Warning
Personal injury hazard exists in the area where you see the sign.

Care of product: Disconnect the power plug by pulling the plug, not the cord.
Disconnect the power plug if the power cord or plug is frayed or otherwise damaged,
if you spill anything into the case, if product is exposed to any excess moisture, if
product is dropped or damaged, if you suspect that the product needs servicing or
repair, and whenever you clean the product.

Service Manual i
Ground the product: Plug the three-wire power cord (with grounding prong) into
grounded AC outlets only. If necessary, contact a licensed electrician to install a
properly grounded outlet.
Symbols as marked on product:
DANGER high voltage:

Protective ground (earth) terminal:

Use caution. Refer to the manual(s) for information:

WARNING: If the product loses the ground connection, usage of knobs and controls
(and other conductive parts) can cause an electrical shock. Electrical product may be
hazardous if misused.

Service Safety Summary

For qualified service personnel only: Refer also to the preceding Users Safety
Summary.
Do not service alone: Do not perform internal service or adjustment of this
product unless another person capable of rendering first aid or resuscitation is present.
Use care when servicing with power on: Dangerous voltages may exist at
several points in this product. To avoid personal injury, do not touch exposed
connections and components while power is on.
Disconnect power before removing the power supply shield, soldering, or replacing
components.
Do not wear jewelry: Remove jewelry prior to servicing. Rings, necklaces, and
other metallic objects could come into contact with dangerous voltages and currents.
Power source: This product is intended to operate from a power source that will not
apply more than 250 volts rms between the supply conductors or between either
supply conductor and ground. A protective ground connection by way of the
grounding conductor in the power cord is essential for safe operation.

ii Phaser 8400/8500/8550 Color Printer

Regulatory Specifications
United States
Xerox has tested this product to electromagnetic emission and immunity standards.
These standards are designed to mitigate interference caused or received by this
product in a typical office environment.

United States (FCC Regulations)

This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to
provide reasonable protection against harmful interference in a residential
installation. This equipment generates, uses, and can radiate radio frequency energy.
If it is not installed and used in accordance with these instructions, it may cause
harmful interference to radio communications. However, there is no guarantee that
interference will not occur in a particular installation. If this equipment does cause
harmful interference to radio or television reception, which can be determined by
turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:

■ Reorient or relocate the receiver.

■ Increase the separation between the equipment and receiver.

■ Connect the equipment into an outlet on a circuit different from that to which the
receiver is connected.

■ Consult the dealer or an experienced radio/television technician for help.

Any changes or modifications not expressly approved by Xerox could void the user's
authority to operate the equipment. To ensure compliance with Part 15 of the FCC
rules, use shielded interface cables.

Canada (Regulations)
This Class B digital apparatus complies with Canadian ICES-003.
Cet appareil numérique de la classe B est conforme à la norme NMB-003 du Canada.

European Union (Declaration of Conformity)

Xerox Corporation declares, under our sole responsibility, that the product to which
this declaration relates is in conformity with the following standards and other
normative documents:

Service Manual iii

Low Voltage Directive 73/23/EEC as amended

EN 60950:2000

Electromagnetic Compatibility Directive 89/336/EEC as amended

EN 55022:1998+A1:2000 +A2:2003

EN 55024:1998+A1:2000 +A2:2003

EN 61000-3-2:2000

EN 61000-3-3:1995+A1:2000

Radio & Telecommunications Terminal Equipment Directive 1999/5/EC

as amended

EN 300 330-2 V1.1.1

EN 300 440-2 V1.1.1

EN 301 489-3 V1.3.1

This product, if used properly in accordance with the user's instructions, is neither
dangerous for the consumer nor for the environment.
A signed copy of the Declaration of Conformity for this product can be obtained from
Xerox.

iv Phaser 8400/8500/8550 Color Printer

Electrostatic Discharge (ESD) Precautions
Some semiconductor components, and the respective sub-assemblies that contain
them, are vulnerable to damage by Electrostatic discharge (ESD). These components
include Integrated Circuits (ICs). Large-Scale Integrated circuits (LSIs), field-effect
transistors and other semiconductor chip components. The following techniques will
reduce the occurrence of component damage caused by static electricity.
Be sure the power is off to the chassis or circuit board, and observe all other safety
precautions.

■ Immediately before handling any semiconductor components assemblies, drain

the electrostatic charge from your body. This can be accomplished by touching an
earth ground source or by wearing a wrist strap device connected to an earth
ground source. Wearing a wrist strap will also prevent accumulation of additional
bodily static charges. Be sure to remove the wrist strap before applying power to
the unit under test to avoid potential shock.

■ After removing a static sensitivity assembly from its anti-static bag, place it on a
grounded conductive surface. If the anti-static bag is conductive, you may ground
the bag and use it as a conductive surface.

■ Do not use freon-propelled chemicals. These can generate electrical charges

sufficient to damage some devices.

■ Do not remove a replacement component or electrical sub-assembly from its

protective package until you are ready to install it.

■ Immediately before removing the protective material from the leads of a

replacement device, touch the protective material to the chassis or circuit
assembly into which the device will be installed.

■ Minimize body motions when handling unpacked replacement devices. Motion

such as your clothes brushing together, or lifting a foot from a carpeted floor can
generate enough static electricity to damage an electro-statically sensitive device.

■ Handle IC’s and EPROM’s carefully to avoid bending pins.

■ Pay attention to the direction of parts when mounting or inserting them on

Printed Circuit Boards (PCB’s).

Service Manual v
ContentsUser Safety Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Regulatory Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Electrostatic Discharge (ESD) Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . v

1 General Information
Printer Introduction and Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Printer Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Control Panel Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
LED Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Control Panel Feature Descriptions. . . . . . . . . . . . . . . . . . . . . . . . 1-5
Menu Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Control Panel Shortcuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Parts of the Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Front View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Right Side View with Printer Interfaces. . . . . . . . . . . . . . . . . . . . . 1-7
Rear View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
Routine Maintenance Items and Consumables. . . . . . . . . . . . . . . . . . . . . 1-9
Printer Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
Physical Dimensions and Clearances . . . . . . . . . . . . . . . . . . . . . 1-10
Functional Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Media and Tray Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12

2 Theory of Operation
Main Printer Subsystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Printer Subsystem Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Process Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Media Path Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Ink Loader. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Printhead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Drum Maintenance System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13
Purge System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
Drum Assembly And Transfix System . . . . . . . . . . . . . . . . . . . . 2-16
Electronics Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19
I/O Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22
Print Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23
Drum Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24
Printing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24
Paper Pick for Tray 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25
Paper Pick for Trays 2 - 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26
Transfixing and Exiting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27
Service Manual
 Duplex Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-30
Transfix and Print Speeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-31
Printer Self-Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-33
Printhead Maintenance Cycle (Eliminate Light Stripes) . . . . . . . 2-33
Paper Preheater Cleaning (Remove Print Smears). . . . . . . . . . . 2-34
Transfix Roller Oiling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-34
Drum Cleaning - Chase Page . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-34
Configuration Card Personality Parameters. . . . . . . . . . . . . . . . . . . . . . 2-35

3 Error Messages and Codes

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Power-Up Error Messages and LED Codes . . . . . . . . . . . . . . . . . . . . . . . 3-3
BIST Error Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
POST Error Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
PEST Error Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
Fault Code Error Message Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . 3-9
Fault Code Error Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Interpreting Fault Codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
1,000.4x Error - 525-Sheet Feeder Faults . . . . . . . . . . . . . . . . . 3-10
2,0XX.4x Error - I/O Circuit Board Fault . . . . . . . . . . . . . . . . . . . 3-11
3,0XX.6x - IPC Program Faults . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
4,0XX.4x Errors - Process Control System Fault . . . . . . . . . . . . 3-13
5,0XX.4x Errors - Y-Axis Sub-System Fault . . . . . . . . . . . . . . . . 3-16
6,0XX.4x Errors - X-Axis Fault . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
7,0XX.4x Errors - Process Motor Gearbox Faults. . . . . . . . . . . . 3-19
8,0XX.xx Error - Wiper/Media Path Gearbox Faults . . . . . . . . . . 3-24
9,0XX.xx Errors - Ink Loader Faults . . . . . . . . . . . . . . . . . . . . . . 3-26
11,0XX.xx Errors - Electronics Module Interface Fault . . . . . . . . 3-27
13,0XX.xx Errors - Thermal Faults . . . . . . . . . . . . . . . . . . . . . . . 3-29
19,0XX.xx Errors - Printhead Calibration faults.. . . . . . . . . . . . . 3-36
31,0XX.4x Errors - Mechanical Initialization Jam. . . . . . . . . . . . 3-37
33,0XX.xx Errors - Tray Manager Device Faults . . . . . . . . . . . . . 3-39
34,0XX.xx Errors - Printhead NVRAM Faults . . . . . . . . . . . . . . . 3-39
36,000.40 Errors - Drum Maintenance Faults . . . . . . . . . . . . . . 3-40
37,0XX.xx Errors - PEST Faults . . . . . . . . . . . . . . . . . . . . . . . . . 3-41
Jam Codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-55
Jam Code Definition Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-57

4 General Troubleshooting
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Hidden Service Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Service Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Service Diagnostics Mode Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
Service Diagnostics Menu Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Phaser 8400/8500/8550 Color Printer

 Check Menu Definition Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
Check / Activators Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
Check Shafts Menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17
Check Paper Path Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20
Check Drive Menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-35
Check Drum Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-42
Check Motors Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-48
Check Misc Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-53
Electronics Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-59
Printer Power-Up Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-59
Mechanical Initialization (8400) . . . . . . . . . . . . . . . . . . . . . . . . . 4-60
Mechanical Initialization (8500/8550). . . . . . . . . . . . . . . . . . . . . 4-62
Miscellaneous Electrical Troubleshooting. . . . . . . . . . . . . . . . . . 4-65
Verifying Power Supply Operation . . . . . . . . . . . . . . . . . . . . . . . 4-75
Measuring AC Power Supply Voltages . . . . . . . . . . . . . . . . . . . . 4-75
Measuring DC Power Supply Voltages . . . . . . . . . . . . . . . . . . . . 4-76
Ensuring Ground Integrity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-77
Testing Motor and Solenoid Resistances . . . . . . . . . . . . . . . . . . 4-78
Paper Path and Media-Based Problems . . . . . . . . . . . . . . . . . . . . . . . . . 4-79
Media-Based Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-79
Paper-Pick Errors - Trays 2, 3, and 4 . . . . . . . . . . . . . . . . . . . . . 4-79
Paper-Pick Errors - Tray 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-80
Preheater and Transfix Jams . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-80
Checking the Process and Media Path Drive. . . . . . . . . . . . . . . . 4-81
Media Skews Passing Through the Paper Path. . . . . . . . . . . . . . 4-81
Operating System and Application Problems . . . . . . . . . . . . . . . . . . . . . 4-82
Testing Communications Ports. . . . . . . . . . . . . . . . . . . . . . . . . . 4-82
Network Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-84
Obtaining Serial Back Channel Trace . . . . . . . . . . . . . . . . . . . . . 4-85

5 Print-Quality Troubleshooting
Print-Quality Problems Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Random Light Stripes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
Predominate Light Stripes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Smudges or Smears . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Printing Too Light or Too Dark . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Not Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Color is Uneven or Color is Wrong . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Streaks or Lines Down the Print . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
Scratches or Marks Parallel to the Long Axis of Printing,
Particularly with Film . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13
White Portion of Print is Colored . . . . . . . . . . . . . . . . . . . . . . . . 5-15
Fuzzy Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-17
Ghosting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20
Poor Small Text Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22
Vertical Lines Appear Wavy . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23

Service Manual
 Oil Streaks on Print . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-24
Incomplete Image Transfer to Paper . . . . . . . . . . . . . . . . . . . . . 5-26
Ink Smears on First Printed Side of Duplex Print . . . . . . . . . . . . 5-28
Repeating Print Defects on Print . . . . . . . . . . . . . . . . . . . . . . . . 5-29
White Stripes (Pinstripes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30
Wrinkling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-31
Image Is Offset or Cut-Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-32
Poor Ink Adhesion, Poor Image Durability . . . . . . . . . . . . . . . . . 5-32
Analyzing Service Test Prints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-33
Test Print Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-33

6 Adjustments and Calibrations

Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Wiper Alignment Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Printer Component Homing Positions and Indicators . . . . . . . . . 6-4
Wiper Assembly Positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Homing the Head Tilt Gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Homing the Process Gear Drive Train . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Printer Calibrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10
Wiper Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10
Jet Substitution Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10
Enabling Jet Substitution Mode (8400) . . . . . . . . . . . . . . . . . . . 6-11
Enabling Jet Substitution Mode (8500/8550) . . . . . . . . . . . . . . 6-11
Disabling Jet Substitution Mode (8400) . . . . . . . . . . . . . . . . . . 6-12
Disabling Jet Substitution Mode (8500/8550) . . . . . . . . . . . . . . 6-12
Resetting NVRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12

7 Cleaning and Maintenance

Service Cleaning Maintenance Procedure . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Pick Roller Cleaning Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5
Maintenance Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5
Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

8 Service Parts Disassembly

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2
Standard Orientation of the Printer . . . . . . . . . . . . . . . . . . . . . . . 8-2
General Notes on Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3
Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
Front Door (Tray 1) Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
Control Panel Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
Front (Control) Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
Right Side Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

Phaser 8400/8500/8550 Color Printer

 Left Side Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7
Exit Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7
Ink Loader Assembly and Door. . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8
Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9
Y-Axis Belt, Y-Axis Tension Spring, and Y-Axis Motor Assembly . 8-9
Printhead Assembly, Right and Left Printhead Restraints. . . . . . 8-12
Head Tilt Solenoid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-18
X-Axis Bias Spring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-19
Printhead Wiper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-20
Media Release Blade Carriage Assembly and Transfix Roller . . . 8-22
Paper Preheater and Deskew Assembly . . . . . . . . . . . . . . . . . . . 8-23
Duplex Roller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-25
Transfix Load Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-26
Transfix Camshaft Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-31
Drum Maintenance Camshaft Assembly . . . . . . . . . . . . . . . . . . . 8-32
Drum Maintenance Pivot Plate Assembly . . . . . . . . . . . . . . . . . . 8-33
Drum Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-34
Purge Pressure Pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-39
Paper Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-40
Exit Module Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-40
Paper Guides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-41
Take Away Roller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-44
Pick Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-45
Media Tray Lift Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-47
Motors, Gears, Solenoids, Clutches, and Fans . . . . . . . . . . . . . . . . . . . . 8-48
Media Drive Gearbox with Two Clutches and Solenoid . . . . . . . . 8-48
Tray 1 Pick Solenoid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-49
Preheater Lift Solenoid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-50
Process Drive Motor and Gearbox . . . . . . . . . . . . . . . . . . . . . . . 8-51
X-Axis Motor Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-53
Head Tilt Compound Gear. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-54
Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-55
Electronics Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-55
Wave Amp Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-56
I/O Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-57
Drum Heater Relay Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-58
NVRAM Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-59
DIMM Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-60
Hard Drive Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-61

9 Parts Lists
Serial Number Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2
Using the Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3
Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4
Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6
Paper Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-8

Service Manual
 Motors, Gears, Solenoids, Clutches, and Fans. . . . . . . . . . . . . . 9-10
Circuit Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-12
Sensors and Flags (Actuators). . . . . . . . . . . . . . . . . . . . . . . . . . 9-14
Xerox Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-16

10 Wiring Diagrams
Main Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2
Main Wiring Diagram (Continued). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3
Right-Side Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4
Right-Side Wiring Diagram (Continued) . . . . . . . . . . . . . . . . . . . . . . . . 10-5
Left-Side Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-6
Left-Side Wiring Diagram (Continued) . . . . . . . . . . . . . . . . . . . . . . . . . 10-7
Inside Front Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-8
Inside Top Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-9
Inside Top - Printhead Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . 10-10

Appendix
Menu Map (8400) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2
Menu Map (8500/8550) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4
Media Margin Specification Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-6
Paper Weight Equivalence Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-7
On-site Printhead Troubleshooting Checklist (8400) . . . . . . . . . . A-8
On-site Printhead Troubleshooting Checklist (8500/8550) . . . . A-13

Index

Phaser 8400/8500/8550 Color Printer

General
Information
In this chapter...
■ Printer Introduction and Overview
■ Printer Configurations
■ Control Panel Configuration
■ Parts of the Printer
■ Routine Maintenance Items and Consumables
■ Printer Specifications

Section
1
Printer Introduction and Overview
The Xerox Phaser® 8400/8500/8550 Color Printer Service Manual is the primary
document used for repairing, maintaining, and troubleshooting the printer.
To ensure understanding of this product, complete the Xerox Phaser 8400/8500/8550
Color Printer Service Training and self-study guide.

Back
Left

Right

Front s8500-002

1-2 Phaser 8400/8500/8550 Color Printer

Printer Configurations
The Configuration Card holds configuration information that enables or disables
built-in features as described below. The first table shows the configuration for the
8400 series. The second table shows the configuration for the 8500 series.

Phaser 8400-Series Printer Configurations

Features 8400B 8400BD 8400N 8400DP 8400DX

Maximum Print Speed 24 24 24 24 24

Memory (Std/Max) 128/512 256/512 128/512 256/512 256/512

MB MB MB MB MB

Hard Drive No No Optional** Optional** Standard

PostScript Fonts 137 137 137 137 137

PCL Fonts 81 81 81 81 81

Japanese Fonts* No No Optional Optional Optional

Job Pipelining No Yes No Yes Yes

Automatic 2-Sided Printing No Standard No Standard Standard

100-Sheet Tray 1 Standard Standard Standard Standard Standard

525-Sheet Tray 2 Standard Standard Standard Standard Standard

525-Sheet Feeder Tray 3 Optional Optional Optional Optional Standard

525-Sheet Feeder Tray 4 Optional Optional Optional Optional Optional

USB, Parallel Connection Standard Standard Standard Standard Standard

10/100 Ethernet No No Standard Standard Standard

Connection

*Japanese fonts are provided for applicable countries per special licensing requirements.
** The following features are not included in this configuration: proof print, saved print,
secure print, and collation.

General Information 1-3

 Phaser 8500/8550 Series Printer Configurations

Phaser Features 8500N 8500DN 8550DP 8550DT 8550DX

Maximum Print Speed 24ppm 24ppm 30ppm 30ppm 30ppm

Memory (Std/Max) 128MB/ 128MB/ 256MB/ 256MB/ 512MB/

1GB 1GB 1GB 1GB 1GB

Hard Drive Optional** Optional** Optional** Optional** Standard

PostScript Fonts 137 137 137 137 137

PCL Fonts 81 81 81 81 81

Job Pipelining No No Yes Yes Yes

Automatic 2-Sided Printing No Yes Yes Yes Yes

100-Sheet Tray 1 Standard Standard Standard Standard Standard

525-Sheet Tray 2 Standard Standard Standard Standard Standard

525-Sheet Feeder Tray 3 No No No Yes Yes

525-Sheet Feeder Tray 4 No No No No Yes

USB Connection Standard Standard Standard Standard Standard

10/100 Ethernet Yes Yes Yes Yes Yes

Connection
** The following features are not included in the Phaser 8400-series printers, but are included
with the Phaser 8500/8550 printers with a hard drive: proof print, saved print, secure print,
personal print, and font storage.

1-4 Phaser 8400/8500/8550 Color Printer

Control Panel Configuration
The Control Panel consists of one tricolor LED, a display window, and six functional
buttons. These buttons navigate the menu system, perform functions, and select
modes of operation for the printer.

LED Indicators
■ Green = Ready to Print ■ Flashing Green = Receiving,
Processing Data, Printing or Power
Saver Mode
■ Flashing Amber = Warning ■ Flashing Red = Error

Control Panel Feature Descriptions

1 3 5 8

Phaser 8500

READY TO PRINT
Walk-Up Features
Information
Paper Tray Setup
Printer Setup
Troubleshooting

2 4 6 7 s8500-003

1 Status Indicator LED: 5 Up Arrow button

Green: Ready to print. Scrolls upward through the menus.
Yellow: Warning condition, printer
continues to print.
Red: Startup sequence or error
condition.
Blinking: Printer is busy or warming
up.

2 Graphic display indicates status 6 Down Arrow button

messages and menus. Scrolls downward through the menus.

3 Cancel button 7 OK button

Cancels the current print job. Accepts the selected setting.

4 Back button 8 Help (?) or Information button

Returns to the previous menu item. Displays a help message with
information about the printer, such as
printer status, error messages, and
maintenance information.

General Information 1-5

Menu Maps
The Customer Menu Map helps you navigate the Control Panel menus. The Menu
Map’s are provided in the appendix section of this manual, see page A-2.
To print the Menu Map:
1. On the Control Panel, select Information, and then press the OK button.
2. Select Menu Map, and then press the OK button to print.
The service diagnostic menu map is detailed in Section 4, see "Service Diagnostics"
on page 4-4 for more information.

Control Panel Shortcuts

Mode or Menu Item Shortcut

Service Tools Menu On the Control Panel, press the Down Arrow button and select
Troubleshooting and press OK.
Then, press the Down Arrow button to select Service Tools and
then press OK.

Service (Internal) (Phaser 8400) Hold the Back and Info button at power up (for about
Diagnostics 30 seconds).
(Phaser 8500/8550) Wait until Control Panel screen turns black, and
then press and hold Back and Help buttons until the message
“Beginning Service Mode” displays.

Set Control Panel Press and hold the Cancel button, and then press the Help button.
language

Bypass protected Press and hold the Cancel button, and then press the Back button.
menus

Jet Substitution Mode (Phaser 8400 only) To add Jet Substitution Mode to the Print
Quality Problems menu:
From the Print Quality Problems menu: press and hold the Up Arrow
button, and then press the Back button .
Phaser 8500/8550 have Jet Substitution in the main menu system
(under Eliminate Light Stripes).

FTTR (Fast Time To Printer goes to the ready state without waiting for thermal
Ready) temperatures to reach the proper operating values. On power-up,
when the Xerox splash screen displays, press and release the Up
Arrow button, then press the Down Arrow button. If the printer
detects ink on the drum, the display indicates a warming-up status.

1-6 Phaser 8400/8500/8550 Color Printer

Parts of the Printer
This section shows the main external components of the printer, including interfaces,
the electronics module, and the internal sensors.

Front View
1. Optional 525-Sheet Feeder Tray 4
9 2. Optional 525-Sheet Feeder Tray 3
7 8 10
6 3. Stan. 525-Sheet Feeder Tray 2
5 4. 100-Sheet Multi-Purpose Tray 1
5. Control Panel
6. Exit cover release
4 7. Front cover release
11 8. Exit cover
9. Ink loader/top cover
3 10.Legal/A4 output tray extension
12 11.Interface cover
2 12.Side door

s8500-004

Right Side View with Printer Interfaces

1. Maintenance kit
2. Waste tray
1 2 3 4
3. Power cord connection
5 4. Power switch
6 5. Parallel port connection
(8400 series only)
7 6. USB connection
7. Configuration card
8 8. Ethernet 10/100 Base-T
connection

s8500-005

General Information 1-7

Rear View
The rear view consists of the printer’s main electronics and power supply, which are
enclosed in a metal case called the Electronics Module. The rear panel allows access
to the Electronics module, RAM, and NVRAM chips. The printer’s hard drive is also
mounted on the rear panel.
When installing a new electronic module in the printer, the following components
need to be transferred from the old board.

4
2

3
1
s8500-006

1. Hard drive (optional) 3. Configuration card (Installed from the

side under the interface cover.)

2. Memory (RAM) DIMM 1 and DIMM 2 4. NVRAM (configuration card handles

NVRAM differences between 8400 and
8500 series).

1-8 Phaser 8400/8500/8550 Color Printer

Routine Maintenance Items and Consumables

3
1 2 3 4

1
s8500-007

Routine Maintenance Items Consumable

1. Maintenance kit 3. Ink

2. Waste tray

Routine Maintenance: Consumable:

Extended Capacity 30,000 cycles (0-20% Ink (8400) 1140 prints

Maintenance Kit coverage) per stick*
(8400 and 8550 only) 20,000-30,000 (20-100% (8500/8550) 1080
coverage) prints per stick*

Startup Maintenance (8500/8550) 10,000

Kit cycles for black and white,
5500 cycles for color.
(8400) 10,000 cycles
regardless of colors used.

Waste Tray Empty every 7 purges.

*Consumable capacity is based on 5% coverage per color on plain A4 paper.

General Information 1-9

Printer Specifications

Physical Dimensions and Clearances

Print Engine Only Value
Width: 422 mm (16.6 in.)

Depth: 514 mm (20.24 in.)

Height: 368 mm (14.48 in.)

Weight: 26.8 kg (59 lb.)

Optional 525-Sheet Feeder Value

Width: 422 mm (16.6 in.)

Depth: 514 mm (20.24 in.)

Height: 132 mm (5.2 in.)

Weight: 5.4 kg (12 lb.)

Minimum Clearances Supplemental Information

Left side and rear - 102 mm (4 in.) Required for airflow.

Right side - 394 mm (15.5 in.) Required for maintenance kit and waste tray access,
and airflow.

Front - Unrestricted Required for media tray and jam access.

Top - 559 mm (22 in.) printer only Required for inkload and jam access.

Bottom - No obstruction between Required for airflow.

mounting surface and printer

Min. install width - 711 mm (28 in.) Requires placing printer at an angle to remove waste
tray.

A. Absolute Minimum B. Recommended Minimum

6.0 6.0 4.0 15.5
4.0

4.0
24.0

28.0 35.5
Front

Note: All dimensions in inches

1-10 Phaser 8400/8500/8550 Color Printer

Functional Specifications
Characteristic Specification

Printing Process Solid-ink

Color Medium Yellow, cyan, magenta, and black ink sticks, each shape-coded. The
printer uses the subtractive color system to produce the colors red,
green, and blue.

Operating Modes and (8400)

Resolutions Fast Color (300x300 dpi), Standard (300x450 dpi), Enhanced
(563x400 dpi), High Resolution/Photo (525x2400)
(8500/8550)
Fast Color (225 x 400 dpi), Standard (300x450 dpi), Enhanced (525
x 400 dpi), High Resolution/Photo (525x2400)

Maximum Operating 24 ppm (8400 and 8500 series)

Printing Speed 30 ppm (8550 series)
First-Print-Out As low as 6 seconds
(in seconds, Letter/A4)

Warm-Up Time: 12 minutes (8400), 15 minutes (8500/8550)

From Off (cold start) 4 minutes
From Power Saver

Electrical Specifications
Characteristic Specification

115 Volt 230 Volt

Primary line voltages 90 - 140 VAC 180 - 264 VAC

Primary line voltage 47 - 63 Hz 47 - 63 Hz
frequency range

Power consumption 1250 W (peak) - 1000 typical 1250 W (peak) 1000 typical
180 W (idle) 180 W (idle)
230 W (average during printing) 230 W (average during printing)

ENERGY STAR® 43 W 43 W

Environmental Specifications
Nominal Operating Environment

Temperature 10º - 32º C (50º - 90º F) operating

20º - 25º C (68º - 77º F) Best jam performance

Humidity 10% - 80% RH Non-Condensing operating

General Information 1-11

Media and Tray Specifications

Single-sided Only
2-Sided (Duplex)
Tray 1 Only
Any Tray
Paper Size Paper Type Paper Weight/Media Type

Letter (8.5 x Plain Paper 60–120 g/m2 (16–32 lb. Bond) l l

11 in.) or or Letterhead l l
121–220 g/m2 (32–59 lb. Bond)
A4 (210 x
297 mm) Transparency Phaser Professional Solid Ink l l
Transparencies

Card Stock 100–120 g/m2 (37–44 lb. Cover) l l

l l
121–220 g/m2 (44–80 lb. Cover)

Labels Phaser Color Printing Labels l l

Special Phaser Professional Solid Ink Business l l

Cards

Phaser Professional Solid Ink High l l

Resolution Photo Paper

Phaser Premium Postcards l l

Phaser Weatherproof Paper l l

Phaser Trifold Brochures l l

Legal (8.5 x 60–120 g/m2 (16–32 lb. Bond) l l

14 in.)

Executive (7.25 x 60–120 g/m2 (16–32 lb. Bond) l l

10.5 in.) or 2 l l
121–220 g/m (32–59 lb. Bond)
A5 (148 x
210 mm)

Statement (5.5 x 60–120 g/m2 (16–32 lb. Bond) l l

8.5 in.)

US Folio (8.5 x 60–120 g/m2 (16–32 lb. Bond) l l

13 in.)

A6 (105 x 60–120 g/m2 (16–32 lb. Bond) l l

148 mm)

B5 ISO (176 x 60–120 g/m2 (16–32 lb. Bond) l l

250 mm)

B5 JIS (182 x 60–120 g/m2 (16–32 lb. Bond) l l

257 mm)

1-12 Phaser 8400/8500/8550 Color Printer

 Single-sided Only
2-Sided (Duplex)
Tray 1 Only
Any Tray
Paper Size Paper Type Paper Weight/Media Type

Index Cards (3 x l l
5 in.)

Custom NOTE: Print custom size media from Tray 1 only.

Maximum: 216 mm wide x 355 mm l l l

long (8.5 in. wide x 14 in. long)

Minimum: 75 mm wide x 127 mm long l l

(3 in. wide x 5 in. long)

Minimum: 139.7 mm wide x 210 mm l l

long (5.5 in. wide x 8.3 in. long)

Envelopes Any Tray #10 Commercial (4.12 x 9.5 in.) l l

DL (110 x 220 mm) l l
C5 (162 x 229 mm) l l

Tray 1 Only #5-1/2 (Baronial 4.375 x 5.75 in.) l l

#6-3/4 (3.625 x 6.5 in.) l l
Monarch (3.87 x 7.5 in.) l l
Brochure (6 x 9 in.) l l
A7 (5.25 x 7.25 in.) l l
Choukei 3 Gou (120 x 235 mm) l l
Choukei 4 Gou (90 x 205 mm) l l

NOTE: Some wrinkling and embossing may occur when printing envelopes. See “Printing” on
the User Documentation CD-ROM for information on how to minimize these
occurrences.
NOTE: 2-sided printing can only be used for paper with widths greater than 5.5 in. (139.7 mm)
and lengths greater than 8.3 in. (210.82 mm).

General Information 1-13

Theory of
Operation
In this chapter...
■ Main Printer Subsystems
■ Print Process
■ Printer Self-Maintenance
■ Configuration Card Personality Parameters

Section
2
Main Printer Subsystems

Transfix System Ink Loader

Drum
Duplex Print Path Printhead

*Power Supply

*Main
Board

*Hard Drive

*Configuration
Card

*Power Control
Board
Paper Preheater
(and Deskew) Ink Waste Tray Paper/Media Tray
Drum Maintenance Kit
Wave Amp
Wiper Assembly

*Part of the Electronics Module

s8500-008

Printer Subsystem Overview

The printer is made up of eight major subsystems, which are described in this section:
■ Process Drive
■ Media Path Drive
■ Ink Loader
■ Printhead
■ Drum Maintenance System
■ Purge System
■ Drum Assembly and Transfix Assembly
■ Electronics Module

2-2 Phaser 8400/8500/8550 Color Printer

The Process Drive: is Transmits torque to two main camshaft assemblies. One
camshaft assembly controls the transfix roller loading, and the other controls the drum
maintenance system and printhead tilt system.
The Media Path Drive: Controls each roller in the paper transport system. The
paper transport system consists of a drive motor, a gearbox assembly and three
solenoids. The media path drive motor also controls the movement of the wiper
assembly and the headlock mechanism through a gear train and solenoid on the exit
module.
The Ink Loader: Melts the solid ink as ink is required by the printhead. The melted
ink drops into the ink reservoirs of the printhead underneath the ink loader.
The Printhead: Interfaces with the electronics of the printer to jet ink onto the
drum surface to create an image. The print head includes 1236 interleaved jets (309 of
each primary color) to provide the ability to electronically turn off a weak or missing
jet to restore image quality.
The Drum Maintenance System: Creates a thin intermediate liquid transfer
surface, a layer of silicone oil, on the surface of the drum prior to printing. The oil
keeps the ink from sticking to the drum’s surface and facilitates its transfer to the
sheet of paper or transparency film.
The Purge System: Uses air pressure and a wiper blade to remove any debris or
air bubbles that may be obstructing the printhead nozzles.
The Drum Assembly and Transfix System: Form the key portion of where
imaging takes place. The image is first printed as a "mirror" image on the rotating
drum. A sheet of warmed media feeds from the preheater and passes between the
drum and the transfix roller. The process gear train then loads the transfix system and
presses the paper to the drum to adhere the image as the drum spins in the transfix
direction.
The Electronics Subsystem: includes the Electronics Module (also known as the
E-can); which contains the main board, the image processor board, the power control
board, and the power supply board. Distributed in the print engine are: the Wave
Amplifier board, Input/Output board, and Drum Heater Relay board.

Theory of Operation 2-3

Process Drive
The process drive is an open loop system that transmits torque to two main camshaft
assemblies. One camshaft assembly controls the transfix roller loading, and the other
controls the drum maintenance system and printhead tilt system. A small DC
servomotor powers the process drive gearbox to rotate the gears to specific positions
during the printing process. The process drive is able to actuate each camshaft system
independently through the use of the swing arm in the gear train.
The rotational direction of the motor controls the operation of the transfix and drum
maintenance system. When the process motor rotates in one direction, the swing gear
engages the lower gears. When the motor rotates in the opposite direction, the upper
gears are engaged.
Since the system is open loop, special attention to the home position of the process
drive gears and the mating camshaft gears is critical. The process drive gearbox is
mechanically keyed upon installation via gear orientations. These gear orientations
allow the printer subsystems to self-home during operation. If either the gearbox or
cam gears is out of home during installation, the printer does not function properly.

Process drive Swing gear

Imaging Transfix

Transfix
Camshaft

Process
Motor
Gear
Process
Motor Gear

Drum
Maintenance
Camshaft

Drum Maintenance
s8500-009

2-4 Phaser 8400/8500/8550 Color Printer

Media Path Drive
The media path drive gearbox and motor assembly controls each roller in the paper
transport system. A gear train located behind the motor connects it to the exit rollers,
which are built into the exit module. Gear trains located within the media path drive
assembly, along with two clutches and a solenoid, allow the motor to control the pick,
take away, duplex, and deskew rollers.
A unique swing gear allows the pick roller and take away roller to rotate in the same
direction regardless of the direction the motor is rotating.

Motor

Media path drive

Swing gear

Duplex Roller

Deskew Roller

Takeaway Roller

Pick Roller

s8500-010

Theory of Operation 2-5

Ink Loader
The ink loader consists of four parallel channels with an ink melting element at the
end of each channel. Coil springs exert pressure on four ink sticks to load one unique
color in each channel. When the printhead requires ink, the melting element of the
appropriate color melts the end of the ink stick. The melted ink drips into the ink
reservoirs of the printhead underneath. Sensors in the ink loader alert the customer to
install more ink sticks before the printer completely consumes the current sticks.
If the ink level sensors inside the printhead detect that the printhead has run out of ink,
but the ink low/out sensors are not activated, the Control Panel reports an “Ink Jam”
error. The Phaser 8400 features a single Ink-Out sensor, which activates when there is
no ink stick in any of the four ink channels. This condition activates the sensor flag.
The 8500/8550 features an Ink-Out sensor in each ink stick channel. Each sensor
determines if the individual channel is empty. The sensors also determine the count of
the ink sticks as they pass by the Ink-Out sensor flag.

Ink Loader Door

Ink Stick

Ink Melt Units Ink Low Sensor (1 Sensor for 8400)

Ink Out Sensors (4 Sensors, One For Each Color

For 8500/8550)
Printhead

s8500-011

2-6 Phaser 8400/8500/8550 Color Printer

Printhead
The printhead is the heart of the printer, spanning nearly the length of the drum. Using
its 1236 jet nozzles (309 jets for each primary color), with a horizontal motion of
slightly less than 5 mm (0.2 inches), the printhead can print the entire image on the
rotating drum. The printhead provides one size ink drop, which is used for all print-
quality modes.

Reservoir
Drum

Printhead

Jet Stack
Head Driver Board

Purge Tube

s8500-012

Theory of Operation 2-7

 Printhead
Ink Loader

Black

Funnel Filter Yellow

Level Sense Probe

Purge Valve

Ink
Cyan

Magenta

s8500-013

The printhead’s jet stack is fabricated from a stack of chemically etched steel plates
which are brazed together to form the jet array. Channels formed by the stacked plates
route ink past the 1236 individual, piezo-electric crystal-driven diaphragms, which
force the ink in droplets out the 1236 corresponding nozzles. Looking at the printhead
face, the nozzles are arranged in 12 rows, in color order KYKYKYCMCMCM, where
K = black, Y = yellow, C = cyan, and M = magenta. During the printing process, the
printhead would only have to travel approximately 14 pixels horizontally to provide
complete coverage. However, the printhead travels much further, depending on print
resolution, to interlace each jet with the output of neighboring jets.
The jet array bonds to a cast aluminum ink reservoir, which supplies the molten ink to
the jet array. Heaters in the reservoir and the jet array maintain the ink at a printing
temperature of about 140 degrees centigrade.

2-8 Phaser 8400/8500/8550 Color Printer

 X-Axis Hook Printhead
X-Axis X-Axis Nose X-Axis
Shaft Shaft Cone
Tension Spring Motor
Gear

Drum
s8500-014

X-Axis or lateral movement of the printhead is accomplished using a stepper motor

driving a fine-thread screw system. The printhead, mounted to the X-Axis shaft,
moves laterally across the surface of the drum.
To find the printhead home position, the X-Axis system drives the printhead in an
open-loop. The printhead is driven against the left printer frame for a few seconds,
and then reversed a set distance. A tension spring links to the printhead’s left shaft and
provides a preloaded tension to allow the printhead to move smoothly.

Theory of Operation 2-9

Printhead Tilt
The printhead is able to rotate into four basic positions:
1. Printhead lock / ship position (19.5 degrees): The printhead restraint pins are
resting against the right and left locks. In this position, the printhead tilt arm/
follower is free of the tilt cam, and the head is secured for shipping.
2. Wipe position (12 degrees): The printhead tilt arm/follower is engaged with the
tilt cam, and the head overload spring contact is engaged with the overload
spring-plate to provide the correct force for the wiper.
3. Standby position (20.9 degrees): Allows the wiper to clear the printhead in
order to be in the start wipe printhead position, and also allow the printhead locks
to pivot and lock or unlock the printhead. In this position, the printhead tilt arm/
follower is engaged at the standby position of the tilt cam.
4. Print position (0 degrees): The printhead is forward and resting against the right
and left head-to-drum buttons. The head-to-drum buttons define the space
between the jet stack and the drum.
The tilt cam tilts the head into the basic four positions listed above. The cam has five
special features and associated functions:
1. The cam is combined with a missing tooth gear that allows the cam to be inactive
in the print position, which frees the process drive to perform other printer
operations.
2. The cam has a latching feature to unlatch and latch the missing tooth gear to
engage the printhead tilt drive train.
3. The cam profile has a standby dwell (the portion of the cam that has a constant
radius), that holds the printhead back in the standby position.
4. The cam profile has a wipe dwell the holds the printhead back in the wipe
position.
5. The cam profile increases the power consumption at a specific phase of rotation.
This allows the software to identify a power consumption footprint that alerts the
printer to a fault when the head is locked in error.
The printhead is tilted away from the drum and locked for shipping. The printhead is
locked if the head lock indicator is above the level of the output tray. When the
printhead is locked in the shipping position there are three key restraining elements:
1. The printhead is restrained from rotating from the shipping position by pins
extending from both ends of the printhead into a pocket. These pockets are
defined by dampening pads that limit motion to the lockarms that pivot into the
lock position, limiting forward motion toward the drum. The wiper carriage holds
the locks in the lock position, which are normally spring-loaded in the unlocked
position.
2. The printhead is restrained at the X-Axis shafts by the right and left head
restraints that limit motion at both ends of the printhead.
3. The printhead is limited to the nominal motion of 1.7 mm in the X-Axis (left /
right side motion when the printhead is back and locked) by the right lock and the
left home stop on the left side frame.

2-10 Phaser 8400/8500/8550 Color Printer

 Printhead Restraint
Drum

DM Cam Gear
Printhead

Tilt Gear (Engaged)

Tilt Gear s8500-015

In the print position (0 degrees), the printhead is forward and rests against the right
and left head-to-drum buttons. The head-to-drum buttons define the space between
the jet stack and the drum. When the process drive is activated, it drives the drum
maintenance camshaft to engage the tilt gear train. The tilt cam tilts the printhead into
the print position. The cam is combined with a missing tooth gear that allows the cam
to be inactive in the print position, freeing the process drive to perform other printer
operations.
The cam has a latching mechanism to unlatch and latch the missing tooth gear to
engage the printhead tilt drive train. The cam’s latching mechanism also holds the tilt
gear in place. A leaf spring applies constant pressure to engage the gear when the
latching mechanism is released. The arm of the latching mechanism is inside the
frame; the rest is visible, outside the frame. Arrows located on the latching
mechanism and on the frame indicate when the printhead is in print position. When
the arrows on the latching mechanism and frame align, the printhead is in the print
position and the tilt gear disengages from the process drive. Phaser 8500/8550
printers have a new solenoid that is actuated and deactuated when the tilt cam gear
rotates to the respective engaged and disengaged positions.

Theory of Operation 2-11

The latching mechanism is actuated by a small movement of the wiper coupled with
the head-tilt solenoid. The action of the solenoid ensures that the head-tilt gear
engages the tilt drive gear. Through a follower gear, the compound gear drives the tilt
cam gear clockwise. A cam follower, mounted on the lower end of the tilt arm,
follows the rotating tilt cam gear and tilts the printhead. After one revolution of the tilt
gear, the latching mechanism is pulled back into position by the return spring in the
8400, and by the tilt gear solenoid in the 8500/8550.
As viewed from the left side of the printer, when the arrows do not align, the tilt gear
is engaged.

Head Tilt Compond Gear Tilt Gear Engaged Tilt Drive Gear
s8500-133

To accommodate printhead maintenance, the printhead can be tilted back away from
the drum. This creates room for the wiper to be moved into position in front of the
printhead faceplate. The process drive drives the gears to the tilt compound gear train.
The drum maintenance camshaft drives the gear train to tilt the printhead.

2-12 Phaser 8400/8500/8550 Color Printer

Drum Maintenance System
The drum maintenance system creates a thin intermediate liquid transfer surface, a
layer of silicone oil, on the surface of the drum prior to printing. The oil keeps the ink
from sticking to the drum’s surface and facilitates its transfer to the sheet of paper or
transparency film. The oil is contained in porous foam rollers made from rolled paper/
fiber material.
Prior to each print, the process motor drives a cam to raise the pivot plate, which
raises the oil roller against the rotating drum. The same cam raises the compliant
wiper blade to assure that the oil film is smooth and even across the drum’s surface.
The process drive rotates in one direction. This rotates the drum maintenance
camshaft and raises the drum maintenance system to the drum. The process drive then
rotates in the opposite direction to lower the drum maintenance system. The blade
removes oil and drains it back into the maintenance kit drawer through a felt filter.
The oil roller can then reuse the oil. As the drum completes one rotation, the rotating
cam lowers the oil roller and then lowers the blade.
The drum has a floating deadband; the narrow section of the drum containing excess
oil and other debris. The oil bar is left on the drum surface when the blade is removed
from the drum. This oil bar location is controlled to keep it outside of the print area.
An EEPROM chip, built-in to the maintenance kit, stores the number of oiling cycles
performed by the drum maintenance system. The EEPROM stores the number of
prints remaining to track consumable life. At printer startup, four oiling cycles are
performed to condition the drum.

Drum

Oil on Drum

Blade

Drum Maintenance Maintenance Roller

Camshaft
Drum Maintenance Pivot Plate
s8500-016

Theory of Operation 2-13

Purge System
Proper printhead operation is dependant on the correct operation of the Purge System.
The purge system uses air pressure and a wiper blade to purge any debris or air
bubbles that may be obstructing the printhead nozzles. The waste ink that is expelled
during the purge is funneled into the waste tray. Following the purge, a wipe operation
is performed on the faceplate using the wiper blade. After the wipe, a cleaning page is
printed.

Wiper Blade

2.5 sec

Printhead Purge Tube

Purge Pump

s8500-017

To perform a printhead maintenance cycle, the printhead is first tilted away from the
drum, to allow the wiper assembly to pass by. The wiper blade is then raised in front
of the printhead. Wiper movement is governed by the media path drive, by engaging a
clutch on the exit shaft of the printer. The purge pump applies pressure to the ink
reservoir for approximately 2.5 seconds. Valves in the reservoir seal when pressure is
applied. The pressurization ejects a small amount of ink from the jets. Following the
pressure purge, the printhead is tilted into the wiper assembly and the wipe cycle
begins. The pump runs again with the solenoid for approximately 30 seconds,
creating a neutral balance between pressure and ink. The wiper blade lowers and
wipes excess ink from the jets into the ink waste tray. A proper purge will layer the
length of the waste tray with a single layer of ink about 20 mm wide.

2-14 Phaser 8400/8500/8550 Color Printer

The level of the ink in the reservoir is kept at a constant level. If the pressure purge
tubing is pinched, the printhead may not purge properly. In addition, because the
purge tubing also acts as a vent to atmosphere when not purging, a more serious
failure may occur if the ink overfills. Overfilling may trap air in the reservoir, which
would prevent the melted ink from entering the reservoir.

Warning
When servicing the printer be careful of the purge system as it passes the
printhead. If a damaged wiper blade of the purge system catches on the
printhead, it could propel hot liquid ink upward into your face.

30 Sec

Printhead Purge Tube

Solenoid Valve

Purge Pump

(Open During Wiper Action)

Wiper Assembly

Printhead

Drum

Wiper

s8500-018

Theory of Operation 2-15

Drum Assembly And Transfix System
The drum assembly and transfix system form the key portion of the printer where
imaging takes place. The drum assembly and transfix system are separate, yet
interrelated. This section discusses the drum assembly. The next section provides
more detail on the transfix system.
In operation, the image to be printed on paper is first “printed” on the rapidly rotating
drum. The paper preheater heats a sheet of paper or transparency film to prepare it for
the image transfer process. The heated paper is then passed between the drum (now
rotating much more slowly) and the transfix roller. The pressure between the drum
and the transfix roller transfers the image to the sheet of paper. An encoder disk and
sensor on the left end of the drum monitors the drum’s speed and position.

th
Transfix Roller Pa
r
pe
Pa

Paper Preheater

Drum
Drum Heater s8500-019

The drum heater heats the surface of the drum to about 60o C (140o F) for imaging.
The drum heater does not rotate. The heater is inside the drum, and is controlled by
the drum heater relay board. The drum heater consists of two resistive heater coils that
operate in series for 220 V and in parallel for 110 V operation. The drum heater relay
board controls the series/parallel operation. A temperature sensor in contact with the
drum surface monitors the drum temperature. The main board interprets the sensor’s
signal and turns on the drum heater and drum fan to heat the drum, or turns on the
drum fan alone to cool the drum.

2-16 Phaser 8400/8500/8550 Color Printer

A closed-loop servomotor drives the drum assembly. Through a single reduction belt
drive, the servomotor rotates the drum at a high speed for imaging and a constant low
speed for image transfer to paper. The Y-Axis uses an active tension system to allow
the pulley to float while the spring actively adjusts the tension.

Note
The drum rotates in different directions for each process.

■ Transfix CW
■ Maintenance CCW
■ Printing CCW

Single Reduction Belt Drive

Pulley

Drum Temperature Sensor

CW

Fan
CCW

Air Direction
Y-Axis Motor Y-Axis 8400
Tension Spring Encoder 8500/8550
s8500-020

Warning
Always keep your fingers away from the drum drive system; it
uses a closed-loop servo drive system, which is inherently
dangerous. Since the motor speeds up if it senses the drum drive
system slowing down, fingers caught in the drum belts and gears
can be severely injured.

Theory of Operation 2-17

Transfix System
The transfix roller applies pressure to the back side of the paper as it moves between
the transfix roller and drum. This pressure transfers the image from the drum to the
paper. A set of springs determines how much pressure the transfix roller applies in the
load module against the drum. The pressure must be uniform across the length of the
transfix roller to avoid paper wrinkles and light spots on the prints.
After the transfix roller engages, the drum rotates to advance the paper during the
transfix process. The drum continues to advance the paper until the transfix roller
disengages. The action of the process drive lifts and lowers the transfix roller. The
upper gears of the process drive move to rotate the transfix camshaft to bring the
transfix roller into contact with the drum. The gears reverse to rotate the transfix roller
back to its original position, except when printing from Tray 1 or on envelopes. The
transfix load springs and double lever arms increase the force when the camshaft
engages.

Warning
Never attempt to adjust or increase the transfix pressure on the springs.

s8500-021

2-18 Phaser 8400/8500/8550 Color Printer

Electronics Module
The electronics module includes the main board, the power control board, and the
power supply. The electronics module is a Field Replaceable Unit (FRU) assembly.

Main Board
The main board performs the image processing functions. Communication ports on
the board receive the print job image data and convert it to drive signals for the
printhead. The main board also contains the mechanical process controller, which
commands the function of the power control board. The main board sends signals
through the power control board to the wave amp board, which amplifies the signal
that drives the jets on the printhead. The main board supports Non-Volatile RAM
(NVRAM), memory, the hard drive, input/output ports, and the configuration card.
NVRAM: The NVRAM memory device, located on the main board, stores Control
Panel defaults, network settings, calibration data, copy counts, usage profile data, and
the printer serial number, which is also referred to as the Engine Tracking
Number (ETN). When the electronics module is replaced, the NVRAM must be
transferred to the main board in the replacement electronics module.
Memory: For Phaser 8400 printers, the main board supports two PC 133 compatible
SO-DIMM SDRAM memory modules (128 to 256 MB). Phaser 8500/8550 printers
support SIMMs instead of DIMMs. Supported sizes are 128, 256, and 512 MB.
Printers ship with a minimum of 128 MB and support a maximum of 1024 MB
Hard Drive Support: A hard drive IDE cable plugs into the main board from the
hard drive board. A separate power cable must plug into the power control board from
the hard drive board to provide signals and power for the hard drive board.
Input/Output Ports: In the Phaser 8400, the main board provides support for
Ethernet (not supported on the B and BD printer configurations), Parallel, and USB
2.0 external I/O interfaces. For the 8500/8550, the main board provides support for
Ethernet (all printer configurations), and USB 2.0 external I/O interfaces. The 8500/
8550 configurations do not include parallel interfaces.

Configuration Card
The configuration card is a thumbnail-sized device that plugs into the side of the
electronics module. This device stores printer information and interacts with the
printer's NVRAM chip. The configuration card supports the transfer of printer model
and network configuration information from a failed printer to a replacement printer.
When replacing the electronics module, you must transfer the configuration card to
the replacement electronics module.
Information stored on the configuration card includes the feature value, ethernet
address, and personality parameters. The card reads a combination of feature values
and the printer hardware capabilities; this will determine the printer model
configuration.You can migrate the configuration card from one printer to another to

Theory of Operation 2-19

transfer the printer configuration. Feature value and ethernet address are configured at
the factory, and are “read only”. The feature value is fixed in the configuration card
and does not change. Ethernet address is stored only on the configuration card and
cannot be rewritten. The Ethernet address is not written to the NVRAM chip.
Personality parameters are a subset of network configuration parameters, which are
populated to the configuration card when the customer configures the printer. The
personality parameters are copied (“shadowed”), from the main board's NVRAM chip
to the configuration card during the normal operation of the printer. When the
configuration card is inserted into a new printer, the personality parameters on the
configuration card are written into the NVRAM chip of the new printer. When a
printer is powered on, if it contains the configuration card of another printer, the
personality parameters copy automatically to the NVRAM chip. When removing the
configuration card for the Phaser 8400, the printer reboots as a B (non-networking)
configuration. Refer to the “Configuration Card Personality Parameters” section at the
end of this chapter for a detailed list of “shadowed” personality parameters.

Power Control Board

The power control board distributes drive voltages to operate the printer’s various
motors, solenoids, and clutches. The power control board also provides the interface
that returns information from the printer's sensors to the main board. The sensors
track mechanical and thermal functions, such as the position and temperature of the
printhead. The power control board also generates regulated +/- 12 V and 5 V from
unregulated +/-15 V power.

Power Supply
There are no field adjustments necessary on the power supply. In general, the power
supply has two main sections: the AC section and the DC section. In the AC section,
power routes to 10 triacs. Under main board logic control, the triacs supply AC power
to the 10 heaters in the printer.
Two fuses provide current protection to the triacs. Fuse F2 and F3 protect the power
supply from a shorted triac from a defective heater. If the F2 or F3 fuses blow, it is
best to replace the electronics module (and, of course, the defective heater), rather
than the fuse. With the fuse replaced but the triac shorted, AC power may be applied
to the heater. However, each time the main board turns on a triac to activate a heater, it
is turned on for only a fraction of a second. The main board must constantly re-
address each heater it wants to control. If the print engine firmware should fail, the
heaters would automatically shut off.
Thermal fuses also protect the printer. A thermal fuse opens in the unlikely event of a
“runaway” heater following a hardware failure. The drum and the paper preheater
thermal fuses are located on the paper preheater. Additional thermal fuses are located
on the printhead and on the ink melting elements.

2-20 Phaser 8400/8500/8550 Color Printer

The DC power supply generates + 3.3 V, +/- 15 V, and +/- 50 V. These voltages
provide direct or regulated voltage values to various circuits in the printer. The power
control board regulates +/- 15 V to +/- 12 and other voltages. The main board also has
regulators providing + 5 V, + 2.5 V, and + 1.8 V. The power supply outputs + 3.3 V in
ENERGY STAR mode. Fuse F1 provides protection for the switching power supply
in the DC section.

Warning
Do not touch the power supply; AC line voltages are present. The
power switch does not disconnect power from the printer. The
power switch signals the supply and the printer logic to begin a
shutdown sequence.

AC Line
F3
Line
S1 Gnd Ref
F2
Neutral
AC Neutral

D P
r I I I I r r
r n n n n e e
u e js js
h k k k k s s r I
m 2 1
t 4 3 2 1
H
H 1
8 3
H H
9 1
2 H
1
1 H
1
0

AC Line AC Neutral H
4
Serial H
Control 3
Low Interface
Switcher H
2
+3.3 V H13 H
H12 1
H11
H10 Vcc
H9
REG
H8 uProcessor
+15 V H4
-15 V H3
+50 V H2
-50 V H1
Vss
s8500-022

Theory of Operation 2-21

I/O Board
The I/O Board acts as the “eyes”, “ears”, and “hands” for the electronics module. All
sensor and switch readings are input into the I/O Board. The I/O Board then translates
these states into encoded information that it sends over a serial data bus (I/O Board
data cable) to the electronics module. The electronic module has no direct connection
to sensors, switches, or solenoids. In order to activate a clutch or solenoid, the
electronic module sends a command to the I/O Board, which processes the command
and activates the appropriate device.

Sensors
Sensors throughout all the major subsystems provide indicators of vital print
operations. The following graphic identifies the location of the printer’s sensors.

Ink Out
(x1 for 8400; x4 for 8500/8550) Ink Low
Strip Sensor Paper Exit Sensor
Exit Door Sensor
Drum
Temperature
Sensor

Preheater
Drum
Sensor
Position
Encoder
Front Door
Sensor

Deskew Tray Paper

Sensor Size Sensor
Tray Empty Board
Sensor (Also in
Trays 3 & 4)

Pick Sensor
(525-sheet Tray Lift Sensor
Feeder) (Also in Trays 3 & 4)
s8500-023

2-22 Phaser 8400/8500/8550 Color Printer

Print Process
Once the printer processes an image and creates a printing bitmap, the print cycle
begins. Sensors maintain correct operating temperatures for the printhead and drum.
Sensors also monitor ink levels in the reservoirs. If necessary, the ink loader adds ink.
At the ready state, the print process consists of the following steps:

■ Drum Preparation

■ Printing

■ Paper Pick

■ Transfixing and Exiting

Warning
Keep your fingers away from the Y-Axis drum rotation drive
system; the closed-loop servo drive system is inherently
dangerous. Fingers caught in the belts and gears will result in
serious injuries.

Theory of Operation 2-23

Drum Preparation
To prepare the drum, the drum maintenance system applies a thin coating of silicone
to the surface of the drum. The process drive first rotates the drum maintenance
camshaft. As the drum rotates, the cams on the ends of the camshaft push against
followers on each side of the drum maintenance system, forcing the oil roller and
blade against the drum. The saturated roller evenly distributes oil on the drum as it
rotates.

Drum

Oil on Drum

Blade

Drum Maintenance Maintenance Roller

Camshaft
Drum Maintenance Pivot Plate
s8500-016

Printing
To print, the drum begins to rotates at a speed dependent upon print resolution. As the
drum reaches the correct speed, the jets begin to fire to deposit the image on the oiled
portion of the drum. As the jets fire, the printhead moves from right to left to complete
the image on the drum.
When printing, the printer performs a “six-jet interlace”, in which each jet lays down
a particular number of pixel columns, depending on the print resolution. Each jet lays
down one pixel column for each drum rotation, which varies from eight to 16
rotations, depending on the print resolution. Interlacing “averages out” the variability
between jets as it interlaces each jet with other jets. In some test prints, the printhead
moves to the right and lays down 309 parallel bands of ink. Each band is composed of
15 pixel columns of dots from an individual jet.
Jet substitution allows a better performing jet to be used in place of a missing or
poorly performing neighboring jet. When the printer is in the jet substitution mode,
the printhead makes a second, right to left movement to deposit the pixel columns of
the substituted jets. See "Jet Substitution Mode" on page 6-10.
2-24 Phaser 8400/8500/8550 Color Printer
Paper Pick for Tray 1
To pick a sheet of paper, the Tray 1 solenoid is fired, and the drive gear rotates slightly
to engage with the drive train. A bias force from the lift plate against a rotating cam
causes the roller to rotate enough so the missing tooth gear engages the drive train.
This allows the lift plate and paper stack to rotate against the pick roller. The pick
roller then rotates to pick the paper. A separator pad assembly prevents multiple
sheets from being picked by the pick roller.
Key differences in the Tray 1 pick process include:

■ Optimized lift plate force to support heavier paper.

■ 100-sheet capacity.

■ Pick roller to create the buckle for the deskew process.

■ Pick roller drive to disengage when the door is opened and closed.

■ Pivoting separator pad to prevent it from binding.

Drive Gear
Cam
Pick Roller

Spring Loaded Lift Plate Separator Pad

s8500-024

Theory of Operation 2-25

Paper Pick for Trays 2 - 4
Note
Trays 3 and 4 are 525-Sheet Feeders.

For Trays 2 through 4, the paper pick process is different than the pick process used
by Tray 1. To pick a sheet of paper, the media path drive starts, and the pick clutch
engages, which turns the pick roller and the nudger roller. The nudge roller advances
one sheet of paper forward into the pick nip. The retard roller prevents two sheets
from advancing. The sheet of paper continues past the take away rollers until the sheet
completes the deskew process. When using the optional 525-sheet feeder, paper is
pre-picked from the tray and staged in the paper path while the printer is printing
previous pages.
The deskew process uses a reverse/buckle deskew for all three paper paths. The paper
is driven against the non-rotating rollers, which are reversing during simplex, causing
a buckle in the paper ensuring the leading edge is straighten to prevent skewing. The
deskew rollers do not reverse during duplex printing.

Strip Sensor Exit Sensor

Preheat Exit Sensor

Deskew Roller

Deskew Sensor
Pick Roller
Nudger Roller
Retard Roller

s8500-025

2-26 Phaser 8400/8500/8550 Color Printer

Transfixing and Exiting
Transfixing and exiting consists of four major functions:
1. Staging the paper for rendezvous with the image on the drum and transfix roller
nip.
2. Loading the transfix roller and engaging the drum stripper blade assembly.
3. Stripping the paper from the drum.
4. Exiting the paper from the printer, or exiting the paper for (2-sided) duplex
printing.
Tripping the preheat exit sensor (see previous illustration) sets up a series of events,
which take place on a predetermined schedule. Paper is transported through the
preheater to thermally prepare it for transfixing. The preheat sensor detects the
paper’s presence, and accurately references the leading edge of the paper with the
image on the drum.
Based on the timing information from the paper preheater, the leading edge of the
media is advanced to the transfix nip.
Once the paper is stopped in the transfix nip, the process motor gears move to rotate
the transfix camshaft to bring the transfix roller into contact with the drum (see
illustrations on following pages). The transfix roller nip applies the load necessary to
transfer the image to the paper from the drum.
At the point where the transfix roller loads, but before the drum begins to rotate, the
paper stripper solenoid engages. The paper stripper solenoid energizes the paper
stripper. The solenoid mounts on the upper inner duplex guide and activates the strip
solenoid lever, which in turn rotates the stripper carriage until it hits the transfix
ground pins. This action causes the stripper blade to drop onto the deadband of the
drum.
After the transfix roller and the stripper engage, the drum rotates to advance the paper
and transfix the image. The stripper blade catches the leading edge of the sheet of
paper and separates it from the drum. After the leading edge of the paper is beyond
the stripper blade, the stripper solenoid de-energizes.
When the solenoid is de-energized, the solenoid return spring provides a force to
move the solenoid plunger out of the solenoid coil which rotates the stripper carriage
back to its ready position.
Once the entire image is transferred, the drum stops rotating and the process drive lifts
the transfix roller. The media path drive now rotates the exit rollers in the correct
direction to pull the paper out. However, the deskew clutch is de energized so the
deskew rollers are not driven during transfix. The exit rollers deposit the paper into
the output tray, ending the print cycle.

Theory of Operation 2-27

 Transfer Roller

Transfix Load Arm

Transfix Load
Module

Transfix
Load
Spring Transfix
Cam
Drum

Process Drive
Transfix Roller Gear Swing Arm Gear
Transfix Cam

s8500-026

2-28 Phaser 8400/8500/8550 Color Printer

 Release Blade

Strip Solenoid

Exit Sensor
Transfix Roller

Preheat Sensor

Strip
Sensor

Paper Preheater
s8500-027

Theory of Operation 2-29

Duplex Printing
When duplex printing, the exit rollers pull the paper to a predetermined location, such
that the trailing edge of the paper is adjacent to the exit rollers. Then, the exit rollers
pull the paper back into the duplex path. The paper deskews against a non-rotating
deskew nip. From this point on, the print is processed through the paper preheater and
transfix system to the exit tray in the same manner as a single-sided print.
Phaser 8500/8550 printers include a preheater lift solenoid that increases the physical
spacing between the preheater plates when printing the second side of duplex prints.
The increased spacing prevents the paper from rubbing as hard against the plates,
which can cause smearing to occur. Since the Phaser 8500/8550 preheater operates at
a higher temperature than the Phaser 8400, the solenoid is not needed on Phaser
8400 printers.
Exit Sensor
Strip Sensor

Preheat Sensor

Duplex Roller

Deskew Sensor
Preheater Lift Solenoid
(Phaser 8500/8550 Only)
Exit Roller
Duplex Roller

s8500-028

2-30 Phaser 8400/8500/8550 Color Printer

Transfix and Print Speeds
Transfix Speeds

Characteristic Setpoint, Paper Media

Fast Color Standard Enhanced High Res/

Photo

Peak Transfix Speed, 20 ips (8400) 17 ips (8400) 13 ips (8400) 7 ips (8400)
Simplex tray feed 25 ips (8500) 25 ips (8500) 20 ips (8500) 10 ips (8500)

Peak Transfix Speed, 5 ips (8400) 5 ips (8400 5 ips (8400 5 ips (8400)
Duplex 10 ips (8500) 10 ips (8500) 10 ips (8500) 10 ips (8500)

Peak Transfix Speed, 20 ips 17 ips 13 ips 7 ips

Legal

Peak Transfix Speed, 13 ips 7 ips 7 ips 7 ips

Tray 1

First Sheet Transfix 7 ips 7 ips 7 ips 7 ips

Speed

Setpoint, OHP Media

Peak Transfix Speed 5 ips

Approximate Print Speeds (8400 Series)

Tray (Source) /
Simplex, A4 Paper Auto Duplex, A4 Paper
Resolution

Tray 1

Fast Color (300x300 dpi) 10 pages per minute (ppm) 10 sides per minute (spm)

Standard (300x450 dpi) 9 ppm 9 spm

Enhanced (563x400 dpi) 8 ppm 4 spm

High Res/Photo (525 x 6 ppm 3 spm

2400)

PCL 600 x 300 Mode 6.5 ppm

PCL 600 x 600 Mode 3 ppm

Tray 2 - 4

Fast Color (300 x 300 dpi) 24 ppm 15 spm

Standard (300 x 450 dpi) 18 ppm 13 spm

Enhanced (563 x 400 dpi) 12 ppm 11 spm

Theory of Operation 2-31

Approximate Print Speeds (8400 Series) (Continued)

Tray (Source) /
Simplex, A4 Paper Auto Duplex, A4 Paper
Resolution

High Res/Photo (525x2400) 7 ppm 7 spm

PCL 600 x 300 Mode 13 ppm

PCL 600 x 600 Mode 6 ppm

Approximate Print Speeds (8500/8550 Series)

Tray (Source) /
Simplex, A4 Paper Auto Duplex, A4 Paper
Resolution

Tray 1

Fast Color (225 x 400 dpi) 12 pages per minute (ppm) 8.5 sides per minute (spm)

Standard (300 x 450 dpi) 9 ppm 7 spm

Enhanced (525 x 450 dpi) 6 ppm 5 spm

High Res/Photo (525 x 3.5 ppm 3 spm

2400 dpi)

PCL 600 x 300 Mode 6.5 ppm

PCL 600 x 600 Mode 3 ppm

Trays 2 - 4

Fast Color (225 x 300 dpi) 30 ppm 17 spm

Standard (300 x 450 dpi) 24 ppm 14 spm

Enhanced (525 x 450 dpi) 16 ppm 10 spm

High Res/Photo (525 x 10 ppm 6 spm

2400 dpi)

PCL 600 x 300 Mode 16 ppm

PCL 600 x 600 Mode 8ppm

2-32 Phaser 8400/8500/8550 Color Printer

Printer Self-Maintenance
To maintain peak operation, reliability, and print quality, the printer has several
automatic or semi-automatic maintenance functions. These functions may be started
automatically after a certain number of prints or during printer startup, or they may be
started by the customer if a print-quality defect is noted.
■ Printhead Maintenance Cycle (Eliminate Light Stripes)
■ Paper Preheater Cleaning (Remove Print Smears)
■ Transfix Roller Oiling
■ Drum Cleaning (Chase Page)

Printhead Maintenance Cycle (Eliminate Light Stripes)

The printhead maintenance cleaning cycle removes bubbles or foreign matter that
cause a printhead jet to malfunction. Three basic actions take place during a cleaning
cycle:
■ Purging
■ Wiping
■ Printing the Cleaning Page

There is one basic type of cleaning cycle performed by the purge system. The first
customer purge and the manufacturing purge consist of two basic cleaning cycles
performed sequentially. A cleaning cycle is performed when the printer is first
powered on, if the ink reservoir has cooled to the point that a cleaning cycle is
triggered. A cleaning cycle is not performed when the printer is coming out of
standby mode. Refer to the purge system topic in this chapter for more detail on the
printhead maintenance cycle.

Warning
When servicing the printer be careful of the purge system as it passes the
printhead. If a damaged wiper blade of the purge system catches on the
printhead, it could propel hot liquid ink upward into your face.

Theory of Operation 2-33

Paper Preheater Cleaning (Remove Print Smears)
This customer-initiated cleaning procedure is selected by choosing Remove Print
Smears on the Control Panel’s Print Quality Problems menu. This procedure
cleans ink out of the paper preheater that may have been deposited there. Heavier-
weight, high-grade quality paper works best for this procedure. Ink can also be
deposited if a jammed print, with ink on it, was pulled backwards through the paper
preheater.
In the paper preheater cleaning cycle, these events take place:
1. The customer selects the Remove Print Smears menu item.
2. The printer overheats the paper preheater to about 110o C, softening ink trapped
inside the paper preheater. Ordinarily the paper preheater runs at temperatures of
between 60o C and 70o C for paper or transparency film printing.
3. The printer picks and passes approximately 12-24 sheets of paper through the
print path. The first few sheets absorb and remove ink from the paper preheater.
The printer continues to pass sheets of paper though to cool the preheater until
normal operating temperature is reached. If duplex capability is enabled, 5 sheets
of paper go through the simplex paper path and up to 20 sheets go through the
duplex paper path.
4. The printer returns to the Print Quality Problems menu.
Because of the higher paper temperatures involved, this function can also be used to
clean the drum surface of ink deposits caused by a contaminated blade on the drum
maintenance system.

Transfix Roller Oiling

Oiling the transfix roller prevents ink from sticking to it. Every 50 prints, the printer
performs a transfix roller oiling cycle. During this cycle, oil is applied to the drum as
it would be during a print cycle. The transfix roller then lowers against the drum and
the drum rotates, transferring some of the oil to the transfix roller. Finally, the transfix
roller raises to its standby position.

Drum Cleaning - Chase Page

The printer performs a drum cleaning with a chase page automatically anytime a
paper jam occurs. The chase page transfers any image, which may not be complete,
off the drum. The printer then attempts to reprint the print that jammed. The chase
page is processed the same as a regular print, except that the drum is not oiled and no
image is printed on the drum (since an image is already printed on the drum).

2-34 Phaser 8400/8500/8550 Color Printer

Configuration Card Personality Parameters
Configuration Card “Shadowed” Personality Parameters

NCL Subject NCL Item Size (bytes)

N/A “version” not NCL version (of the layout of personality 4

parameter parameters)

NEST Base Printer Name 48

NEST SysAdmin Contact 128 (truncated from 256)

NEST Printer Location 128 (truncated from 256)

NEST Asset Identifier 128 (truncated from 256)

IP Host Name 64

IP Domain Name 256

IP Network Mask 4

IP IP Address 4

IP Default Gateway 4

IP BOOTP/DHCP 1

IP DDNS 1

IP SMTP Server 256

IP IP Source 1

IP TCP/IP 1

IP AutoIP 1

IP DHCP Vendor Class ID 48

DNS RESOLVER Primary Name Server IP Address 4

DNS RESOLVER Secondary Name Server IP Address 4

DNS RESOLVER MulticastDNS 1

NBNS (WINS) Enable 1

NBNS (WINS) WINS Note Type 1

NBNS (WINS) Primary WINS Server 4

NBNS (WINS) Secondary WINS Server 4

Ethernet Speed 1

HTTP On 1

Theory of Operation 2-35

Configuration Card “Shadowed” Personality Parameters (Continued)

NCL Subject NCL Item Size (bytes)

HTTP Information Forwarding 1

HTTP SMTP Server Automatic 1

HTTP Legal Settings 1

HTTP Admin_Password 11

HTTP Admin_Username 11

HTTP KeyUser_Password 11

HTTP KeyUser_Username 11

HTTP Admin_HostAccessList 256

HTTP KeyUser_HostAccessList 256

Notify On 1

IPP Authentication Scheme 1

IPP IPP user name 11

IPP IPP password 11

FTP Login Password 33

Security Print Hosts 256

AppSocket On 1

AppSocket Enabled 1

LPR On 1

LPR Enabled 1

FTP On 1

FTP Enabled 1

IPP On 1

IPP Enabled 1

MIME On 1

MIME Enabled 1

EtherTalk On 1

EtherTalk Enabled 1

PSERVER On 1

2-36 Phaser 8400/8500/8550 Color Printer

Configuration Card “Shadowed” Personality Parameters (Continued)

NCL Subject NCL Item Size (bytes)

PSERVER Enabled 1

PSERVER_IPX Enabled 1

Notes:
1. “Parallel” and “USB”, “On” and “Enabled” parameters have not been identified as
personality parameters. They are not tied to networking.
2. NCL = Nest Configuration Library

Theory of Operation 2-37

Error Messages
and Codes
In this chapter...
■ Introduction
■ Power-Up Error Messages and LED Codes
■ BIST Error Reporting
■ POST Error Reporting
■ PEST Error Reporting
■ Fault Code Error Message Troubleshooting
■ Jam Codes

Section
3
Introduction
This section covers troubleshooting procedures utilizing Control Panel error messages
and codes. Some procedures require running service diagnostic test functions to
verify that a specific printer component is operating correctly. For information on
Service Diagnostics and all internal printer test functions see"Service Diagnostics
Mode Menu" on page 4-5.
For troubleshooting printer problems not associate with, or displaying, an error code
or message, such as startup or power on, media, paper path, print-quality or image
problems, and electrical failures, see "General Troubleshooting" on page 4-1 or
"Print-Quality Troubleshooting" on page 5-1.
Check the main menu for current data and historical error data.
■ Status Page
■ Usage Profile
■ Fault History
■ Diagnostic History

3-2 Phaser 8400/8500/8550 Color Printer

Power-Up Error Messages and LED Codes
The printer has three sets of tests that are run when first powered on:
■ Built-In Self Tests (BIST)
■ Power On Self Tests (POST)
■ Print Engine Self Tests (PEST)

Note
BIST and POST errors are not stored in the fault history logs.

BIST Error Reporting

BIST verifies basic electronics module CPU operation and reports failures by
utilizing the rear interface panel PS and PE LEDs. These tests occur immediately at
power-up, before POST tests are run or the Control Panel is initialized.
The following table defines the blink patterns associated with a failure.
BIST Error Reporting Blink Pattern Definition Table

PE LED PS LED Description

Off or 1 Off or 1 The power supply could not remain regulated when DC power
Blink, and Blink, and was applied so it was shut down.
then off then off Follow the troubleshooting procedures for electrical shorts (see
“Miscellaneous Electrical Troubleshooting” on page 65) and
check the power supply fuses.

On Solid On Solid Initialization failure. The printer is held in reset mode. This can
(dimly) (dimly) be caused by an electronics module fault or a +3.3 V power
supply regulation failure (see "Miscellaneous Electrical
Troubleshooting" on page 4-65). See also, "Verifying Power
Supply Operation" on page 4-75.

Off PS and Boot loader memory test failure. Ensure the printers RAM chips
Control are properly seated and that the correct RAM type for this
Panel 1/2 printer is installed.
sec. blink

1 Rapid CPU bridge and/or PCI bus is not communicating. Reboot the
blinking printer, if the error still occurs, replace the electronics module.

2 Rapid ROM not responding. Reboot the printer, if the error still occurs,
blinking replace the electronics module.

Service Manual 3-3

BIST Error Reporting Blink Pattern Definition Table (Continued)

PE LED PS LED Description

3 Rapid Printer hangs during code initialization.

blinking 1. Unplug all cables from the electronics module.
2. Plug in the power cable.
3. Power on the electronics module (system).
4. If the problem still occurs, reseat the RAM DIMMs.
5. Replace the electronics module. For disassembly, see
"Electronics Module" on page 8-55. For replacement, go to
the Parts List on page 9-3.

POST Error Reporting

POST checks the communication paths within the electronics module and to other
various printer components.
POST testing initializes the Control Panel, and in most cases if an error occurs, a text
message is displayed on the Control Panel along with an LED blink code flashing on
all three LEDs (Control Panel LED, PS LED and PE LED). If initialization of the
Control Panel fails, POST errors will still report using the LED blink patterns. The
sum of the flashes equal the error code. If the code has more than 5 flashes, there is a
brief pause between each set of 5 flashes to make them easier to count. After all
flashes occur within the code, there is a long pause and then the flash pattern repeats.
“Soft” POST errors, that do not prevent the printer from powering up completely, are
displayed on the Control Panel for 5 seconds, and then the printer continues through
the remainder of POST. There are no rear panel LED codes associated with soft
errors. Most soft errors will cause the printer to print a Startup Page with the error
message on it.

Note
Before replacing the electronics module for any POST errors, do the
following:

1. Unplug all wiring and/or cables to the electronics module.

2. Plug in the AC power cable and power on the printer electronics module.
3. If the error blink pattern is now different from the original error reported before
Step 1, the problem may not be in the electronics module, (see "Miscellaneous
Electrical Troubleshooting" on page 4-65).

3-4 Phaser 8400/8500/8550 Color Printer

POST Error Reporting Blink Pattern Definition Table

8500/
8400 8550
Control PS, PE and Control
Panel Control POST Panel
Error Panel LEDs Error Error
Code (for 8400) Type Description Code

01.01 Flutter then Hard Bad error code. 21.1

01 blinks

02.01 Flutter then Hard Failed machine check. 19.1

02 blinks

02.02 Flutter then Hard Printer panic. 19.2

02 blinks

03.01 Flutter only Soft ID read failure. 31.1

03.02 Flutter then Hard Mismatch. 31.2

03 blinks

03.03 Flutter only. Soft Version mismatch. 31.3

03.04 Flutter then Hard Access failure. 31.4

03 blinks

04.01 Flutter and Hard ID read failure. 23.1

then 04
blinks

04.02 Flutter and Hard ID mismatch. 23.2

then 04
blinks

04.03 Flutter and Hard TMVL mismatch, write/read failed. 23.3

then 04
blinks

04.04 Flutter and Hard TMVH mismatch, write/read failed. 23.4

then 04
blinks

05.01 Flutter and Hard Communications error. PLD I/O Board 32.1
then 05 serial, link down/bad parity.
blinks

05.02 Flutter only Soft Communications error. PLD I/O Board 32.2
serial, mismatch.

6.08 N/A Soft IDE drive general failure. Reseat IDE cable 6.808
and power cable. If problem persists,
replace the IDE drive. The printer will work
without the IDE drive.
07.01 Flutter only Soft Control Panel link is invalid or bad parity. 16.1

07.02 Flutter only Soft Control Panel version mismatch. 16.2

Service Manual 3-5

POST Error Reporting Blink Pattern Definition Table (Continued)

8500/
8400 8550
Control PS, PE and Control
Panel Control POST Panel
Error Panel LEDs Error Error
Code (for 8400) Type Description Code

08.01 Flutter only Soft Control Panel failed to initialize, POST soft 16.3
error.

09.01 Flutter only Soft Control Panel data path failure, bad data 16.4
returned.

10.01 Flutter and Hard PLD power control link down. 33.1
then 10
blinks

10.02 Flutter only Soft PLD power control link invalid, mismatch 33.2
error.

11.01 Flutter and Hard EEPROM read failure. 12.1

then 11 1. Check EEPROM orientation.
blinks 2. Replace EEPROM.

11.02 Flutter and Hard EEPROM write failure. 12.2

then 11 1. Check EEPROM orientation.
blinks
2. Replace EEPROM.

11.03 Flutter and Hard EEPROM re-read failure. 12.3

then 11 1. Check EEPROM orientation.
blinks
2. Replace EEPROM.
11.04 Flutter and Hard EEPROM data failure, mismatch error. 12.4
then 11 1. Check EEPROM orientation.
blinks 2. Replace EEPROM.

12.xx Flutter only Soft Configuration card test failure.

1. Check card orientation.
2. Reseat then replace the configuration
card.
NOTE: Printer will work as a base model
(without networking) without the
configuration card (8400 only).
13.01 Flutter and Hard PHY reset failure, reset stuck low. 2.1
then 13
blinks

13.02 Flutter and Hard PHY ID error, mismatch error. 2.2

then 13
blinks
14.xx Flutter and Hard USB ASIC test errors, N2280 netchip read, 19.1
then 14 write, and mismatch errors, POST hard
blinks errors.

3-6 Phaser 8400/8500/8550 Color Printer

POST Error Reporting Blink Pattern Definition Table (Continued)

8500/
8400 8550
Control PS, PE and Control
Panel Control POST Panel
Error Panel LEDs Error Error
Code (for 8400) Type Description Code

15.01 Flutter and Hard CPU interrupt error, spurious CPU 19.3
then 15 interrupts.
blinks

15.02 Flutter and Hard CPU interrupt error, missing CPU 19.4
then 15 interrupts.
blinks

15.03 Flutter and Hard CPU interrupt error, IRQ spurious 19.5
then 15 assertion.
blinks

15.04 Flutter and Hard CPU interrupt error, timer no assertion. 19.6
then 15
blinks

15.05 Flutter and Hard CPU interrupt error, spurious assertion. 19.7
then 15
blinks

15.06 Flutter and Hard CPU interrupt error, no assertion. 19.8

then 15
blinks

15.07 Flutter and Hard CPU interrupt error, spurious assertion. 19.11
then 15
blinks

15.08 Flutter and Hard CPU interrupt error, no assertion. 19.12

then 15
blinks

15.09 Flutter and Hard CPU interrupt error, spurious assertion. 19.13
then 15
blinks

15.10 Flutter and Hard CPU interrupt error, no assertion.

then 15
blinks

15.11 Flutter and Hard CPU interrupt error, IRQ spurious

then 15 assertion.
blinks

16.01 Flutter only Soft Real time clock read failure. 11.1

16.02 Flutter only Soft Real-time clock write failure. 11.2

16.03 Flutter only Soft Real-time clock re-read failure. 11.3

Service Manual 3-7

POST Error Reporting Blink Pattern Definition Table (Continued)

8500/
8400 8550
Control PS, PE and Control
Panel Control POST Panel
Error Panel LEDs Error Error
Code (for 8400) Type Description Code

16.04 Flutter only Soft Real-time clock does not tick. 11.4

Soft Trickle charge failure 11.5

17.01 Flutter and Hard Memory test, less than 128 MB of RAM 13.1
then 17 detected. This is the minimum RAM
blinks required. Add more RAM. Reseat the RAM
SODIMM(s), then replace the RAM
SODIMM(s).

18.01 Flutter and Hard IPCB ID read failure.

then 18
blinks

18.02 Flutter and Hard IPCB ID mismatch.

then 18
blinks

18.03 Flutter and Hard IPCB PCI configuration failure.

then 18
blinks

18.04 Flutter only Soft IPCB version mismatch.

19.01 Flutter and Hard Check and reseat cables. Replace hard
then 19 drive, if necessary.
blinks

PEST Error Reporting

PEST tests occur after POST tests have been run and PostScript has been initialized.
PEST checks the connections and operation of various printer components.
Error codes for PEST tests are displayed on the Control Panel and are all in the
37,XXX.xx series. For troubleshooting PEST error codes, "37,0XX.xx Errors - PEST
Faults" on page 3-41.

3-8 Phaser 8400/8500/8550 Color Printer

Fault Code Error Message Troubleshooting

Fault Code Error Reporting

Fault codes are saved to NVRAM and can be retrieved from the printer’s fault history.
All procedures that ask for a test to be run are referencing tests from within the
“hidden” service diagnostics menu. For more information on service diagnostics tests,
their results, and how to enter into diagnostic mode, see "Service Diagnostics" on
page 4-4.
In normal customer mode, the printer will reboot each time an error occurs. If three of
the same errors occur within 72 hours, or 1000 pages, the fault will be displayed on
the printer’s Control Panel.

Interpreting Fault Codes

■ Failing system (XX,yyy.zz)
■ Failing subsystem (xx,YYY.zz)
■ Checksum (xx,yyy.zZ
■ Type of problem (xx,yyy.Zx)
■ Print engine copy count when the error occurred (xx,yyy.zz:123)
(xx,yyy.4x) Device faults are indicated by a 4 in the tenths place of the
fault code. This indicates a hardware problem. The most common device faults
troubleshooting procedures are documented in this section.
(xx,yyy.6x) Program faults are indicated by a 6 in the tenths place of the
fault code. Unfortunately, there are too many program faults to enumerate them all
and most program faults will not mean anything unless you are intimately familiar
with the code base. Some of the more common program faults are documented in this
section.
(xx,yyy.7z) CPU exceptions are indicated by a 7 in the tenths place of the
fault code. The error code indicates both the PowerPC exception number and the
region of firmware that was executing when the exception occurred: Engine,
PostScript, Network, or Operating System.

Note
A CPU exception can either be caused by hardware or firmware error. Refer to
the infoSMART Knowledge Base for descriptions of the most common faults.

Service Manual 3-9

1,000.4x Error - 525-Sheet Feeder Faults
1,001.46: The upper 525-sheet feeder had an overcurrent condition. The lift motor or
clutch may be shorted.
1,002.47: The lower 525-sheet feeder had an overcurrent condition. The lift motor or
clutch may be shorted.
Troubleshooting Procedure for 525-Sheet Feeder

Step Questions or Actions Yes No

1 1. Unplug all connectors to the optional Complete. Go to Step 2.

525 sheet feeder.
2. Remove the feeder and inspect the
connector.
3. Replace any damaged connectors either on
the 525-sheet feeder or engine.
4. Reseat and reconnect the 525-sheet feeder
to the printer.
5. Did this correct the problem?

2 1. Inspect the pick rollers in the 525-sheet Replace the Go to Step 3.

feeder tray(s). pick assembly.
2. Are the pick rollers damaged, dirty, or not
moving freely?

3 1. Run the Tray [3]/[4] Pick Clutch test. Go to Step 4. Replace the
2. Does the pick clutch operate correctly? 525-sheet
feeder.

4 1. Run the Tray [3]/[4] Lift Motor test. Go to Step 5. Replace the
2. Does the lift motor operate correctly? 525-sheet
feeder.

5 1. Check the wiring from the 525-sheet feeder Replace the Replace the
to the Electronics Module (J390). wiring and go to 525-sheet
2. Is the wiring defective? Step 3. feeder.

1,0XX.6x Errors: 525-Sheet Feeder program faults

a. Reseat the printer onto the 525-sheet feeder.
b. Ensure ground integrity for the printer (see "Ensuring Ground Integrity" on
page 4-77).
c. Reset NVRAM.
d. Replace the 525-sheet feeder.

3-10 Phaser 8400/8500/8550 Color Printer

2,0XX.4x Error - I/O Circuit Board Fault
2,001.47: The print engine cannot detect the presence of the I/O circuit board.
Troubleshooting Procedure for I/O Board

Step Questions or Actions Yes No

1 1. Are all wiring connections to and from the Go to Step 3. Go to Step 2.

I/O Board properly seated?

2 1. Reseat the connections. Go to Step 3. Complete.

2. Power on the printer.
3. Did the error reoccur?

3 1. Test the wiring from the I/O board J840 to Replace the I/O Board.
the power control board J800.

2,0XX.6x Errors - I/O Board Program Faults

2,001.69: The electronics module failed to initialize.
2,002.61: This fault code indicates a problem with the printer program. The engine
firmware was unable to initialize the queues used for inter-task communication.
2,003.62: This fault code indicates a problem with the printer program. The engine
firmware was unable to start the service diagnostics tasks.
2,004.63: Failure to start the print engine in suspend mode.
2,005.64: This fault code indicates a problem with the printer program. ROM could
not be opened for reading (idiags).
2,006.65: This fault code indicates a problem with the printer program. ROM could
not be loaded (idiags).
2,007.66: This fault code indicates a problem with the printer program (idiags) entry
point cannot be found.
a. Reset NVRAM and retest.
b. Ensure ground integrity for the printer (see "Ensuring Ground Integrity" on
page 4-77).
c. Replace the EEPROM chip.
d. Reboot the printer.
2,008.67: Configuration card is missing.
2,009.68: Configuration card is bad.
2,010.69: Configuration card is blank.
2,011.61: Configuration card is for the wrong product.
2,012.62: Configuration card is an invalid model.
a. Turn off printer.
b. Verify that configuration card is correct card for printer.

Service Manual 3-11

 c. Insert or replace configuration card.
d. Turn on printer.
e. If problem continues, replace the electronics module.

3,0XX.6x - IPC Program Faults

There is a communication problem between the engine and PostScript regions.
a. Reset NVRAM, and then retest.
b. Replace the EEPROM chip.

3-12 Phaser 8400/8500/8550 Color Printer

4,0XX.4x Errors - Process Control System Fault
4,017.47: This fault code indicates a problem with the process control system. The
ambient temperature is considered too cold to warm up the printer (less than 10o C).
4,018.48: This fault code indicates a problem with the process control system. The
printhead temperature dropped below the head cleaning needed threshold.
4,020.41: This fault code indicates a problem with the process control system.
Declared when the printer is booted in FTTR (Fast Time to Ready) mode and the
head/wiper contact flag is set in NVRAM. The printer cannot run in FTTR mode with
the head/wiper in contact because it would be unwise to separate the two when the
printer is cold (could tear wiper.) Service requested that this be a device fault in order
to alert the service person to this condition.
4,021.42: This fault code indicates a problem with the process control system.
Declared when the printer is booted in FTTR mode and the drum is dirty. Cleaning
the drum when very cold could increase the chance of gluing media to the drum
surface around the stripper fingers. Service requested that this be a device fault in
order to alert the service person to this condition.
Troubleshooting Procedure for Process Control System

Step Questions and Actions Yes No

1 1. Verify the temperature of the room where the Complete. Go to Step 2.

printer is located (see "Environmental
Specifications" on page 1-11).
2. Is the room temperature too cold for proper
operation of the sytem?
3. Ensure the printer is acclimated to the room
temperature.
4. Did this correct the problem?

2 1. Run the Monitor Heaters tests with all Replace the Go to Step 3.
heaters ON. electronics
2. Are the heaters operating correctly and module.
within specification?

3 1. Inspect the wiring harness to the failed Replace the Replace the
heater. wiring harness problem
2. Is the wiring harness damaged or not to the failed component.
working properly? heater.

Service Manual 3-13

4,024.42: This fault code indicates a problem with the wiper. The wiper is not
aligned properly and engaged the headtilt while in the waste lock position.
Troubleshooting Procedure for 4,024 Error Code

Step Questions and Actions Yes No

1 1. Ensure the process drive system is correctly Is the problem Go to Step 2.

homed as described in "Homing the Process fixed?
Gear Drive Train" on page 6-8.

2 1. Run the Check Wiper Alignment test. Perform the Go to Step 3.

2. Did the test fail? Wiper
Alignment
Procedure and
test again. Go to
Step 3 if the test
fails again.

3 1. Run the Wiper Drive test. Go to Step 4. Go to Step 6.

2. Did the test fail?

4 1. Inspect the wiper drive system and wiper Go to Step 5. Replace the
lock system. Look for ink in the belts. problem
2. Is the wipe system operating correctly? component.

5 1. Inspect the head maintenance clutch. Clean the Go to Step 6.

2. Is there the presence of oil or interior of the
contamination? system and
replace clutch if
necessary.

6 1. Run the Head Maintenance Clutch test. Replace in the Replace the
2. Is the head maintenance clutch operating following order: head
correctly? ■ Exit module maintenance
■ Media drive clutch.
gearbox
■ Wiper blade

4,025.46: This fault code indicates a problem with the process control system.
Cannot successfully home the drum transfix mechanism.
Troubleshooting Procedure for 4,025 Error Code

Step Questions and Actions Yes No

1 1. Check for obstructions around the printhead. Complete. Go to Step 2.

Look for ink shards in gears of the tilt drive.
2. If the printhead is obstructed, remove any
obstruction from the system and reboot.
3. Did this fix the problem?

2 1. Ensure the wiring around the printhead is Re-route all Go to Step 3.

routed properly. wiring to the
2. Is the wiring blocking the printhead? printhead.

3-14 Phaser 8400/8500/8550 Color Printer

Troubleshooting Procedure for 4,025 Error Code (Continued)

Step Questions and Actions Yes No

3 1. Remove the waste tray and printhead and Clean any ink or Go to Step 4.
look for ink build-up in the printer. debris which
2. Is there ink build-up anywhere in the printer? may be
restricting
movement of
the drive train or
printhead.

4 1. Check the process gearbox for damage. Replace the Go to Step 5.

2. Ensure the gears are correctly aligned (see process
"Homing the Process Gear Drive Train" on gearbox.
page 6-8).
3. Is the process gearbox damaged?

5 1. Check the X-axis motor connector for Replace the X- Go to Step 6.

damage. axis motor.
2. Run the X-axis Motor test to check the
X-axis motor current.
3. Did the test fail?

6 1. Run the Tilt Drive test. Replace the

2. Did the test fail? process
gearbox.

4,0XX.6x Process Control Software Fault

a. Reset NVRAM and then retest.
b. Ensure ground integrity for the printer (see "Ensuring Ground Integrity" on
page 4-77).
c. Replace the EEPROM chip.
d. Reboot the printer.

Service Manual 3-15

5,0XX.4x Errors - Y-Axis Sub-System Fault
5,001.41: The drum turned one full revolution without seeing the drum home sensor
activate.
5,002.42: The Y-Axis encoder is not working properly or the drum has stalled.
5,003.43: There is a general problem with the Y-Axis sub-system.
5,004.44: Y-Axis fault_general fail problem with drum motion sub-system.
Troubleshooting Procedure for Y-Axis Sub-System

Step Questions and Actions Yes No

1 1. From the service diagnostic Monitor Menu, Go to Step 2. Go to Step 3.

run the Y-axis Encoder test.
2. Did the test pass?

2 1. Inspect the Y-axis motor connector. Replace the Go to Step 4.

2. Is the wiring faulty? wiring harness
or Y-axis motor.

3 1. Inspect the encoder wiring harness. Replace the Replace the

2. Is the wiring faulty? defective wiring. drum assembly.

4 1. Run the Y-axis Drive test. Go to Step 5. Replace the

2. Check the current values. Y-axis motor.
3. Are the values within normal operating
range?

5 1. Run the Y-axis Belt Tension test. Go to Step 6. Replace the

2. Check the current values. Y-axis belt.
3. Are the values within the normal operating
range?

6 1. Run the Y-axis Motor test. Replace the Replace the

2. Did the tests pass? drum assembly. Y-axis motor.

5,0XX.6x Errors - Program Faults

5,001.63: There is a problem with the Y-Axis sub-system.
5,005.67: If not in the homeless or idle state, the system faults out. Software fault.
5,006.68: Software fault. 5,007.60: Software fault.
5,008.61: PostScript failed to fill the race buffer during imaging. Software fault.

3-16 Phaser 8400/8500/8550 Color Printer

5,009.62: There were errors during imaging. Possible jets on/off outside of the
deadband area. Software fault.
a. Reset NVRAM and retest.
b. Ensure ground integrity for the printer (see "Ensuring Ground Integrity" on
page 4-77).
c. Replace the EEPROM chip.
d. Reboot the printer.

Service Manual 3-17

6,0XX.4x Errors - X-Axis Fault
6,000.41: An X-axis motor current error occurred.
Troubleshooting Procedure for X-Axis Motor

Step Questions and Actions Yes No

1 1. Inspect the printhead power cable and Go to Step 2. Go to Step 3.

heater wiring.
2. Verify the printhead travels smoothly from
left to right.
3. Ensure the printhead does not bind due to
ink spills.
4. Is anything visibly restricting printhead
movement?

2 1. Clear the wiring or ink spill, which is Complete. Go to Step 3.

restricting movement of the printhead.
2. Did this correct the problem?

3 1. Inspect the X-axis wiring harness. Replace the Go to Step 4.

2. Is the wiring damaged or faulty? defective wiring.

4 1. Use service diagnostics to test the X-axis Replace the X- Replace the
drive. axis motor. electronics
2. Did the test fail? module.

6,0XX.6x Errors - Program Faults

6,001.64: The X-axis task received an unexpected message.
6,002.65: Attempt to home the X-axis from a state where homing is not allowed.
6,008.62: Attempt to use the X-axis drive without initializing it.
6,011.65: Attempt to service the X-axis while not in the appropriate state.
6,013.67: Unknown X-axis program fault.
6,017.62: An attempt was made to drive the X-axis using the wrong server.
6,018.63: An attempt was made to move with the X-axis uninitialized.
6,019.64: An attempt was made to move the X-axis from a homeless state.
6,023.68: Could not allocate memory for X-axis home parameters.
6,025.66: An attempt was made to home with the X-axis uninitialized.
6,032.68: Could not find a solution to the described home motion profile.
6,033.60: Could not allocate memory for X-axis move parameters.
a. Reset NVRAM, and then retest.
b. Ensure ground integrity for the printer (see "Ensuring Ground Integrity" on
page 4-77).

3-18 Phaser 8400/8500/8550 Color Printer

7,0XX.4x Errors - Process Motor Gearbox Faults
7,002.44: There is a problem with the process motor sub-system. The process motor
stalled during operation.
Troubleshooting Procedure for 7,002 Error Code

Step Questions and Actions Yes No

1 1. Verify the process drive system is properly Complete. Go to Step 2.

homed, see "Homing the Process Gear
Drive Train" on page 6-8.
2. Did this resolve the problem?

2 1. Use service diagnostics to run the Tilt Axis Go to Step 3. Go to Step 4.

Drive test.
2. Did the test fail?

3 1. Check for and remove any obstructions in Replace the Go to Step 4.

the process gearbox. process
2. Ensure the process drive gears are correctly gearbox.
aligned.
3. Are the gears damaged?

4 1. Use service diagnostics to run the Process Replace the Go to Step 5.

Motor test. process
2. Did the test fail? gearbox

5 1. Use service diagnostics to run the Transfix Verify the Replace the
Drive Slow test. transfix cams process
2. Did the test fail? are not gearbox.
damaged.
Replace
problem
component.

7,006.xx: The head tilt solenoid is not activating the head tilt cam, or the head is not
tilting properly.
Troubleshooting Procedure for 7,006 Error Code

Step Questions and Actions Yes No

1 1. Ensure the process drive system is correctly Is the problem Go to Step 2.

homed as described in "Homing the Process fixed?
Gear Drive Train" on page 6-8.

2 1. Reboot the printer. Go to Step 4. Go to Step 3.

2. Is the tilt-head activating the head tilt cam?

3 1. Is ink blocking the head tilt cam? Remove ink Go to Step 4.

2. Is the tilt-head latch properly installed? spills or reinstall
the head-tilt and
start over with
Step 1.

Service Manual 3-19

Troubleshooting Procedure for 7,006 Error Code (Continued)

Step Questions and Actions Yes No

4 1. Review instructions for 7,008.xx and Follow recommended actions for

7,010.xx fault codes. error codes and reboot the printer.

7,007.49: The process motor stalled while tilting the head.

Troubleshooting Procedure for 7,007 Error Code

Step Questions and Actions Yes No

1 1. Check the printhead wiring for proper Complete. Go to Step 2.

routing.
2. Remove the printhead and inspect the
printhead tilt and drive gears for ink spills.
3. Re-route the wiring.
4. Clean around the gears and printhead.
5. Did this correct the problem?

2 1. To ensure the gears are correctly aligned, Complete. Replace the

homed, and free from damage, see "Homing process
the Process Gear Drive Train" on page 6-8. gearbox.
2. Did this correct the problem?

7,008.41: The head tilt is not engaged, or the printhead is stuck in the tilt position by
the tilt arms.
Troubleshooting Procedure for 7,008 Error Code

Step Questions and Actions Yes No

1 1. Reboot the printer. Go to Step 2. Complete.

2. Did this correct the problem?

2 1. Inspect the printer for ink spills on the head Complete. Go to Step 3.
tilt gear and the drive train.
2. Clean and reboot the printer.
3. Did this correct the problem?

3 1. Ensure that the printhead moves properly Go to Step 4. Remove any

left and right. obstructions or
replace any
defective parts.

4 1. Ensure the gears are correctly aligned and Replace the Go to Step 5.
homed (see "Homing the Process Gear process
Drive Train" on page 6-8). gearbox.
2. Are the gears damaged?

5 1. Check the process gearbox for obstructions Replace the Go to Step 6.

or damaged. process
2. Remove any obstructions. gearbox.
3. Is the gearbox damaged?

3-20 Phaser 8400/8500/8550 Color Printer

Troubleshooting Procedure for 7,008 Error Code (Continued)

Step Questions and Actions Yes No

6 1. Use service diagnostics to run the Tilt Axis Replace the Go to Step 7.
Drive test. process
2. Did the test fail? gearbox.

7 1. Use service diagnostics to run the Head Replace the Go to Step 8.

Maintenance Wiper Clutch test. wiper drive
2. Did the test fail? clutch.

8 1. Perform the Wiper Alignment procedure (see Complete. Go to Step 9.

"Wiper Alignment Procedure" on page 6-2).
2. Did this correct the problem?

9 1. Use service diagnostics to run the Wiper Inspect the Complete.

Drive Test. maintenance
2. Did the test fail? drive system
and replace any
defective parts.

7,009.42: The printhead is tilted back but not properly restrained in the park arms.
Troubleshooting Procedure for 7,009 Error Code

Step Questions and Actions Yes No

1 1. Ensure that the right and left printhead Complete. Go to Step 2.

restraints work correctly and are not cracked
or broken.

2 1. Ensure that the wiper is aligned correctly Complete. Go to Step 3.

(see "Wiper Alignment Procedure" on
page 6-2).

3 1. Check the printhead wiring for proper Complete. Go to Step 4.

routing.
2. Remove the printhead and clean around the
printhead tilt gears.
3. Did this correct the problem?

4 1. Ensure the gears are correctly aligned and Complete. Go to Step 5.

homed (see "Homing the Process Gear
Drive Train" on page 6-8).
2. Did this correct the problem?

5 1. Replace the process gearbox. Complete. Go to Step 6

2. Did this correct the problem?

6 1. Use service diagnostics to run the Head Replace the Go to Step 7.

Maintenance Wiper Clutch test. wiper drive
2. Did the test fail? clutch.

Service Manual 3-21

Troubleshooting Procedure for 7,009 Error Code (Continued)

Step Questions and Actions Yes No

7 1. Use service diagnostics to run the Wiper Inspect the Replace the
Drive test. maintenance exit module
2. Did the test fail? drive system, assembly.
replace any
defective parts.

7,010.43: The printhead is stuck in the tilted position, or is not able to tilt forward to
the print position, due to problems.
7,011.44: This is a soft fault and will not halt the printer.
7,012.45: The drum transfix home sensor is still in a not homed position, after the
return home motion has been completed.
7,014.47: The printhead is not locked in the head tilt restraint spring.
7,015.48: The head tilt restraint spring is out of place.
Troubleshooting Procedure for 7,010 to 7,015 Error Code

Step Questions and Actions Yes No

1 1. Reboot the printer. Complete. Go to Step 2.

2. Did this correct the problem?

2 1. Do the printhead lock arms rotate correctly? Go to Step 3. Repair/replace

the printhead
restraints.

3 1. Has ink spilled ink around the printhead that Clean the Go to Step 5.
prevents the printhead from moving to its printhead area.
center position? You should be able to
manually push the printhead right to left.

4 1. Is the printhead stuck to the wiper blade? Start the printer Go to Step 4.
in diagnostics
mode and run
idiags test
Exercise Heater
- toggle
printhead
heaters to
soften the ink.
Manual
separate the
wiper and
printhead. Set
them in their
home positions.

5 1. Does the X-axis motor drive the printhead to Go to step 6. Troubleshoot

its center position (so it can tilt forward)? the X-axis
drive.

3-22 Phaser 8400/8500/8550 Color Printer

Troubleshooting Procedure for 7,010 to 7,015 Error Code (Continued)

Step Questions and Actions Yes No

6 1. Check the process gearbox for obstructions Complete. Go to Step 7.

or damaged.
2. Ensure the gears are correctly aligned and
homed.
3. Verify the process shaft and drive module
shaft are at their home positions.
4. Did this correct the problem?

7 1. Has ink spilled on the head tilt gear on its Clean the Go to Step 8.
drive train (near left side of the printhead)? gears.

8 1. Use service diagnostics to run the Head Replace the Go to Step 9.

Maintenance Wiper Clutch test. wiper drive
2. Did the test fail? clutch.

9 1. Ensure the wiper is properly aligned. Replace the exit Go to Step 10.
2. Use service diagnostics to run the Wiper module
Drive Test. assembly.
3. Did the test fail?

10 1. Use service diagnostics to run the Load Inspect the Go to step 11.
Maintenance Clutch test. maintenance
2. Did the test fail? drive system,
replace any
defective parts.

11 1. Verify the headtilt gear will engage. You can Go to Step 12. Set the headtilt
manually set the headtilt gear. gear.
2. Is the gear engaged properly?

12 1. Use service diagnostics to run the Tilt Axis Replace the Go to Step 13.
Drive test. process
2. Did the test fail? gearbox.

13 1. Use service diagnostics to run the Process Replace the

Motor test. process motor.
2. Did the test fail?

7,0XX.6x Errors - Program Faults

a. Reset NVRAM and retest.
b. Ensure ground integrity for the printer (see "Ensuring Ground Integrity" on
page 4-77).

Service Manual 3-23

8,0XX.xx Error - Wiper/Media Path Gearbox Faults
8,005.48: The media path motor gearbox stalled while moving the wiper to the home
position.
8,006.49: The wiper cannot verify the home position.
8,007.41: The wiper stalled finding home.
8,008.42: The wiper stalled while trying to move away from the home position.
8,009.43: The media path motor stalled while moving without the clutch engaged.
8,015.49: The media path motor stalled while moving the cap/wipe to the park
position.
8,025.41: The media path motor stalled while moving the cap/wipe from the park
position.
8,035.42: The media path motor stalled while moving the cap/wipe UP.
8,045.43: The media path motor stalled while moving the cap/wipe DOWN.
8,055.44: The media path motor stalled while engaging headtilt.
Troubleshooting Procedure for Wiper/Media Gearbox

Step Questions and Actions Yes No

1 For an 8,005.48 error: Complete. Go to Step 4.

1. Check for paper in the paper path that is
adding drag to the rollers. Look for paper or
wiring interfering with the take away roller.
2. Remove the pick solenoid to view the
meshing of the take away roller’s gears to
the paper path drive module.
3. Did this correct the problem?

2 For an 8,007.41 error: Complete. Go to Step 4.

1. Check for a missing KL-clip securing the
drum maintenance clutch. Replace if
missing.
2. Did this correct the problem?

3 For an 8,009.43 error: Complete. Replace the

1. Ensure that there is no paper in the paper media path
path adding drag to the rollers. drive assembly.
2. Ensure the media paper drive is fully seated
and correctly installed.
3. Remove the pick solenoid to view the
meshing of the take away roller’s gears to
the paper path drive module.
4. Ensure the feed rollers are properly engaged
in the drive gears.
5. Did this correct the problem?

3-24 Phaser 8400/8500/8550 Color Printer

Troubleshooting Procedure for Wiper/Media Gearbox (Continued)

Step Questions and Actions Yes No

4 1. Run the Wiper Drive test. Go to Step 5. Go to Step 6.

2. Did the test pass?

5 1. Run the Wiper Alignment test (see "Wiper Go to Step 7. Go to Step 6.

Alignment Procedure" on page 6-2).
2. Did the test pass?

6 1. Inspect the wiper system for improper Complete. Go to Step 7.

operation, obstructions, or damage (broken
gear or belt). Look for ink in the wiper belt
channels.
2. Ensure the wiper system is properly aligned
(see "Wiper Alignment Procedure" on
page 6-2).
3. Did this correct the problem?

7 1. Run the Head Maintenance Clutch test. Go to Step 8. Replace the

2. Did the test pass? maintenance
clutch.

8 1. Is the head lock mechanism on the right end Go to Step 9. Replace the
of the exit module assembly is functioning exit assembly.
properly?

9 1. Are there obstructions or spilled ink on the Clean the inside

wiper blade, the tilt gear drive path, or under of the printer
the printhead? and retest.
2. Is the waste tray overfilled?

8,0XX.6x Errors - Program Faults

a. Reset NVRAM, and then retest.
b. Ensure ground integrity for the printer (see "Ensuring Ground Integrity" on
page 4-77).

Service Manual 3-25

9,0XX.xx Errors - Ink Loader Faults
9,000.44: These fault indicate a problem with the ink loader.
9,005.49: Ink loader fault. The cyan ink melt heater is on, but the ink does not
appear to be dripping.
9,006.41: Ink loader fault. The magenta ink melt heater is on, but the ink does not
appear to be dripping.
9,007.42: Ink loader fault. The yellow ink melt heater is on, but the ink does not
appear to be dripping.
9,008.43: Ink loader fault. The black ink melt heater is on, but the ink does not
appear to be dripping.
9,015.4x through 9, 018 (8500/8550 only): When a customer opens and closes
the inkloader door to clear an ink jam, the following codes are recorded: 9,01x.41,
where x= 5 for cyan, 6 for magenta, 7 for yellow, and 8 for black.
9,025.4x through 9, 028 (8500/8550 only): When a customer opens and closes
the inkloader door for a second time to clear an ink jam, the following codes are
recorded: 9,02x.41, where x= 5 for cyan, 6 for magenta, 7 for yellow, and 8 for
black.
9,035.43 through 9, 038 (8500/8550 only): Fault codes associated when ink
count flags are stuck after melting 2.5 ink sticks. The following codes are recorded:
9,03x.41, where x= 5 for cyan, 6 for magenta, 7 for yellow, and 8 for black.
Troubleshooting Procedure for Ink Loader

Step Questions and Actions Yes No

1 1. Are the ink sticks all Xerox ink? Are they the Go to Advise
correct ink sticks for the printer model? Step 2. customer. Run
clear ISC Fault
test to clear the
error. The clear
ISC fault menu
item is located
in the internal
diagnostics
function menu.
This must be
performed
following an ink
loader
replacement.

3-26 Phaser 8400/8500/8550 Color Printer

Troubleshooting Procedure for Ink Loader (Continued)

Step Questions and Actions Yes No

2 1. Manually verify that the ink stick is able to Go to Remove any

advance in the ink loader chute. Check for Step 3. blockage and/
broken or wrong type ink sticks. or replace the
ink stick. Run
clear ISC Fault
test to clear the
error. The clear
ISC fault menu
item is located
in the internal
diagnostics
function menu.
This must be
performed
following an ink
loader
replacement.

3 1. Run the appropriate Ink Melt [1, 2, 3, 4] Replace Replace the ink
Heater test. the loader
1 = Yellow printhead. assembly. Run
2 = Cyan clear ISC fault
3 = Magenta test to clear the
4 = Black error. The clear
ISC Fault menu
2. Did the test pass?
item is located
in the internal
diagnostics
function menu.
This must be
performed
following an ink
loader
replacement.

9,009.44 and 9,00X.6x

9,009.44: This fault code indicates a device failure attempting to access NVRAM.
a. Reset NVRAM and retest.
b. Ensure ground integrity for the printer (see "Ensuring Ground Integrity" on
page 4-77).

11,0XX.xx Errors - Electronics Module Interface Fault

11,001.47: Upper 525-sheet feeder broken serial link detected.
11,002.48: Lower 525-sheet feeder broken serial link detected.
11,003.49: Control Panel broken serial link detected.

Service Manual 3-27

11,004.41: Control Panel or I/O board broken serial link detected.
11,005.42: Power control broken serial link detected.
11,006.43: Printhead broken serial link detected.
11,007.44: PCI error detected.
11,008.45: The DMA hardware is not responding.
11,009.46: Communication timeout failure detected.
11,010.47: Hardware version mismatch.
11,011.48: Software version mismatch.
11,012.49: The power control PLD does not match the expected version.
11,013.41: I/O PLD version mismatch.
11,014.42: Control Panel version mismatch.
11,015.43: Printhead PLD version mismatch.
11,016.44: Lower 525-sheet feeder PLD version mismatch.
11,017.45: Upper 525-sheet feeder PLD version mismatch.
11,018.46: Titan version mismatch.
Troubleshooting Procedure for Electronic Module Interface

Step Questions and Actions Yes No

1 1. Ensure ground integrity for the printer. Complete. Go to Step 2.

2. Did this resolve the error?

2 1. Inspect and reseat all connectors. Complete. Go to Step 3.

2. Inspect the gray cable between the I/O board
and the electronics module.
3. Ensure the cables are properly dressed in
the wiring raceway as detailed in the wiring
diagram section of this manual.
4. Did this correct the problem?

3 1. Reset NVRAM and retest. Complete. Go to Step 4.

2. Did this resolve the problem?

■ 11, 001.47 and 11,017.45 Replace tray lift motor or the

electronics module.

■ 11,002.48 and 11, 016.44 Replace lower tray assembly (or

check wiring).

■ 11,003.49 and 11,0014.42 Replace the I/O board.

■ 11,004.41 and 11,013.41 Replace the I/O board or the

Control Panel.

■ 11,006.43 and 11,015.43 Replace the printhead.

■ 11,009.46 Replace the I/O board or the

electronics module.

3-28 Phaser 8400/8500/8550 Color Printer

Troubleshooting Procedure for Electronic Module Interface (Continued)

Step Questions and Actions Yes No

■ For all other 11,000.4x errors: Replace the electronics module.

11,100.60 - Temperature Error

The root problem for this error is temperature sensitivity with the power supply’s
opto-isolator chips. Ensure room temperature is not too high. Ensure also that the
electronics fan runs correctly. If OK, then replace the electronics module.

12,000.60 Errors - Program Faults

a. Reset NVRAM and retest.
b. Ensure ground integrity for the printer (see "Ensuring Ground Integrity" on
page 4-77).

13,0XX.xx Errors - Thermal Faults

13,000.48: Thermal fault.
Troubleshooting Procedures for Error Code 13,000 (Printhead)

Step Questions and Actions Yes No

1 1. Ensure ground integrity for the printer. Complete. Go to Step 2.

2. Did this correct the problem?

2 1. Reset NVRAM and retest. Complete. Go to Step 3.

2. Did this correct the problem?

3 1. Check and reseat all data cables to the Complete. Replace the
printhead. printhead.
2. Did this correct the problem?

13,003.42:
13,007.46:
Troubleshooting Procedures for 13,003 to 13,007 Error Code

Step Questions and Actions Yes No

1 1. Ensure ground integrity for the printer. Complete. Go to Step 2.

2. Did this correct the problem?

2 1. Reset NVRAM and retest. Complete. Replace in the

2. Did this correct the problem? following order:
■NVRAM
■Electronics
module

Service Manual 3-29

13,008.47: The drum heater is too hot.
13,010.49: The drum heater took too long to reach its setpoint.

Troubleshooting Procedure for 13,008 to 13,010 Error Code (Drum Heater)

Step Questions and Actions Yes No

1 1. Verify that the ambient temperature of the Advise Go to Step 2.

room is within the printers optimal customer of
environmental specification (see specification
"Environmental Specifications" on requirements.
page 1-11).
2. Is the room too cold or too hot?

2 1. Ensure ground integrity of the printer (see Go to Step 3. Resolve ground

"Ensuring Ground Integrity" on page 4-77). integrity.
2. Are all components grounded properly?

3 1. Is the error code associated with an Go to Step 4. Go to Step 6.

overheat condition?

4 1. Verify clearance for adequate air flow. Advise Go to Step 5.

2. Are any of the vents blocked? customer of
clearance
specification.

5 1. Using service diagnostics, run the Drum Go to Step 6. Replace the

Fan Motor test. drum fan and/or
2. Did the test pass? the wiring
harness.

6 1. Check the electronics module fan. Go to Step 7. Replace the

2. Is the fan operating correctly? electronics
module fan.

7 1. Using service diagnostics, run the Drum Go to Step 8. Replace the

Temperature Sensor test. drum
2. Did the test pass? temperature
sensor.

8 1. Using service diagnostics, run the Drum Replace the

Heater test. drum
2. Did the test pass? temperature
sensor.

13,067.43: The drum thermistor circuit is open.

13,069.45: The drum thermistor circuit is shorted.
13,071.47: The drum thermistor returned a bad reading, or the reading was corrupted
by ESD (Electrostatic Discharge).

3-30 Phaser 8400/8500/8550 Color Printer

Troubleshooting Procedure for 13,067 to 13,071 Error Code (Drum Thermistor)

Step Questions and Actions Yes No

1 1. Using service diagnostics, run the Drum Go to Step 2. Replace the

Temperature Sensor test. drum
2. Did the test pass? temperature
sensor.

2 1. Inspect the sensor wiring harness. Replace the Replace the

2. Is the wiring free from defects? Is the wiring drum sensor wiring
correctly routed through the pass-thru and temperature harness.
not pinched against the drum assembly sensor.
frame?

13,072.48: The preheater got too hot.

13,074.41: The preheater took too long to reach its setpoint.
13,131.44: The preheater thermistor circuit is open.
13,133.46: The preheater thermistor circuit is shorted.
13,135.48: The preheater thermistor returned a bad reading, or the reading was
corrupted by ESD.
Troubleshooting Procedure for 13,072 to 13,135 Error Code (Preheater)

Step Questions and Actions Yes No

1 1. Verify that the ambient temperature of the Advise Go to Step 2.

room is within the printers optimal customer of
environmental specification (see specification
"Environmental Specifications" on requirements.
page 1-11).
2. Is the room too cold or too hot?

2 1. Run the Preheater test. Replace the I/O Go to Step 3.

2. Did the test pass? board.

3 1. Check the wiring from the preheater. Replace the Replace the
2. Is the wiring connected properly and sound? preheater wiring harness.
board.

13,136.49: The printhead left jetstack heater is too hot.

13,138.42: The printhead left jetstack heater took too long to reach its setpoint.
13,195.45: The printhead left jetstack thermistor circuit is open.
13,197.47: The printhead left jetstack thermistor circuit is shorted.
13,199.49: The printhead left jetstack thermistor returned a bad reading, or the
reading was corrupted by ESD.

Service Manual 3-31

Troubleshooting Procedure for 13,136 to 13,199 Error Code (Printhead)

Step Questions and Actions Yes No

1 1. Verify that the ambient temperature of the Advise Go to Step 2.

room is within the printers optimal customer of
environmental specification (see environmental
"Environmental Specifications" on specification
page 1-11). requirements.
2. Is the room too cold or too hot?

2 1. Ensure ground integrity of the printer (see Go to Step 3. Resolve ground

"Ensuring Ground Integrity" on page 4-77). integrity.
2. Are all components grounded properly?

3 1. Use service diagnostics to run the Left Go to Step 4. Replace the

Jetstack Temperature test. printhead.
2. Did the test pass?

4 1. Check and reseat all wiring to the printhead. Complete. Replace the
2. Did this correct the problem? printhead.

3-32 Phaser 8400/8500/8550 Color Printer

13,200.41: The printhead right jetstack heater is too hot.
13,202.43: The printhead right jetstack heater took too long to reach its setpoint.
13,259.46: The printhead right jetstack thermistor circuit is open.
13,261.48: The printhead right jetstack thermistor circuit is shorted.
13,263.41: The printhead right jetstack thermistor returned a bad reading, or the
reading was corrupted by ESD.
Troubleshooting Procedure for 13,200 to 13,263 Error Code (Printhead)

Step Questions and Actions Yes No

1 1. Verify that the ambient temperature of the Advise Go to Step 2.

room is within the printer’s optimal customer of
environmental specification (see specification
"Environmental Specifications" on requirements.
page 1-11).
2. Is the room too cold or too hot?

2 1. Ensure the ground integrity of the printer Go to Step 3. Resolve ground

(see "Ensuring Ground Integrity" on integrity.
page 4-77).
2. Are all components grounded properly?

3 1. Run the Right Jetstack Temperature test. Go to Step 4. Replace the

2. Did the test pass? printhead.

4 1. Check and reseat all wiring to the printhead. Complete. Replace the
2. Did this correct the problem? printhead.

13,264.42: The printhead reservoir heater got too hot.

13,266.44: The printhead reservoir heater took too long to reach its setpoint.
13,323.47: The printhead reservoir thermistor circuit is open.
13,325.49: The printhead reservoir thermistor circuit is shorted.
13,327.42: The printhead reservoir thermistor returned a bad reading, or the reading
was corrupted by ESD.
Troubleshooting Procedure for 13,264 to 13,327 Error Code (Printhead)

Step Questions and Actions Yes No

1 1. Verify that the ambient temperature of the Advise Go to Step 2.

room is within the printer’s optimal customer of
environmental specification (see specification
"Environmental Specifications" on requirements.
page 1-11).
2. Is the room too cold or too hot?

Service Manual 3-33

Troubleshooting Procedure for 13,264 to 13,327 Error Code (Printhead) (Continued)

Step Questions and Actions Yes No

2 1. Ensure ground integrity of the printer (see Go to Step 3. Resolve ground

"Ensuring Ground Integrity" on page 4-77). integrity.
2. Are all components grounded properly?

3 1. Run the printhead Reservoir Temperature Go to Step 4. Replace the

test. printhead.
2. Did the test pass?

4 1. Check and reseat all wiring to the printhead. Complete. Replace the
2. Did this correct the problem? printhead.

13,328.43: The ink loader CYAN heater is too hot.

13,330.45: The ink loader CYAN heater took too long to reach its setpoint.
13,387.48: The ink loader CYAN thermistor circuit is open.
13,389.41: The ink loader CYAN thermistor circuit is shorted.
13,391.43: The ink loader CYAN thermistor returned a bad reading, or was
corrupted by ESD.
13,392.44: The ink loader MAGENTA heater is too hot.
13,394.46: The ink loader MAGENTA heater took too long to reach its setpoint.
13,451.49: The ink loader MAGENTA thermistor circuit is open.
13,453.42: The ink loader MAGENTA thermistor circuit is shorted.
13,455.44: The ink loader MAGENTA thermistor returned a bad reading, or ESD
corruption.
13,456.45: The ink loader YELLOW heater got too hot.
13,458.47: The ink loader YELLOW heater took too long to reach its setpoint.
13,515.41: The ink loader YELLOW thermistor circuit is open.
13,517.43: The ink loader YELLOW thermistor circuit is shorted.
13,519.45: The ink loader YELLOW thermistor returned a bad reading, or ESD
corruption.
13,520.46: The ink loader BLACK heater got too hot.
13,522.48: The ink loader BLACK heater took too long to reach its setpoint.
13,579.42: The ink loader BLACK thermistor circuit is open.
13,581.44: The ink loader BLACK thermistor circuit is shorted.
13,583.46: The ink loader BLACK thermistor returned a bad reading, or ESD
corruption.

3-34 Phaser 8400/8500/8550 Color Printer

Troubleshooting Procedure for 13,326 to 13,583 Error Code (Ink Loader)

Step Questions and Actions Yes No

1 1. Verify that the ambient temperature of the Advise Go to Step 2.

room is within the printers optimal customer of
environmental specification (see specification
"Environmental Specifications" on requirements.
page 1-11).
2. Is the room too cold or too hot?

2 1. Ensure ground integrity of the printer (see Go to Step 3. Resolve ground

"Ensuring Ground Integrity" on page 4-77). integrity.
2. Are all components grounded properly?

3 1. Inspect and reseat the wiring to the ink Go to Step 4. Replace the I/O
loader. Check for open wires. board or the
2. Did this correct the problem? combined right
cable.

4 1. Run the appropriate Ink Melt test. Replace the ink

1 = Yellow loader.
2 = Cyan
3 = Magenta
4 = Black
2. Did the test pass?

13,000.6x Errors - Program Faults

13,001.62: Thermals failed to read from printer NVRAM.
13,002.63: Value is not in valid range.
13,003.64: Thermal control task received an unexpected message.
13,004.65: Thermal control task was expecting initialization message, but received
other.
13,005.66: Thermal code tried to command a segment ID that did not exist.
13,006.67: Thermal code tried to command a segment ID that did not exist.
13,007.68: Thermal power manager task was expecting initialization message, but
received other.
13,008.60: Thermal power manager task received an unexpected message.
a. Reset NVRAM and retest.
b. Ensure ground integrity for the printer (see "Ensuring Ground Integrity" on
page 4-77).

Service Manual 3-35

19,0XX.xx Errors - Printhead Calibration faults.
19,001.46: HFD server failed due to NVRAM operation. This fault only occurs
when the printer is set in manufacturing mode. Program fault.
19,002.47: Attempted to perform a printhead operation without the printhead
NVRAM data being loaded.
19,003.48: Scale and offset error is too large. The voltages measured have more than
a 20% error from their expected values. Something is wrong with the electronics
module or the wave amplifier.
19,004.40: The printhead and the electronics module do not match. Contact
escalated Service Support Representative for information to clear fault.
19,005.63: Wave amp overcurrent. This error can occur in too-low humidity
environments. Printer self-resets.
Troubleshooting Procedure for Printhead Calibration

Step Questions and Actions Yes No

1 1. Check and reseat all wiring to the printhead. Complete. Replace in the
2. Did this correct the problem? following order:
■Printhead
■Electronics
Module

19,0XX.6x - Errors
19,001.68 thru 19,039.61: Waveform printhead calibration program faults.
a. Reset NVRAM, and then retest.
b. Replace the NVRAM chip.

21,000.69 Errors - Diagnostic Code Version Mismatch

a. The diagnostic firmware does not match the engine firmware. Update the
diagnostic firmware for the printer. If a code updated ROM daughter board is
installed on the main board, remove the board so the printer boots using the
main board’s code and diagnostics.

22,0XX.6x Errors - Jam Codes

a. For jam codes, "Jam Codes" on page 3-55.

23,0XX.6x Errors - NVRAM Fault

a. Reset NVRAM, and then retest.
b. Replace the NVRAM.

3-36 Phaser 8400/8500/8550 Color Printer

26,0XX.6x Errors - Printing Faults
a. Reboot the printer if one of these faults occur.

26,962 Errors - “Fall Out” Code

a. Check the previous error in the fault history and troubleshoot that code.

27,0XX.6x Errors - Profile Library

a. Ensure the ground integrity of the printer (see "Ensuring Ground Integrity"
on page 4-77).

29,0XX.6x Errors - Jam Manager

a. Reset NVRAM, and then retest.
b. Replace the NVRAM.

31,0XX.4x Errors - Mechanical Initialization Jam

31,001.40: Mechanical initialization jam fault.
Troubleshooting Procedure for Mechanical Unit Jam

Step Questions and Actions Yes No

1 1. Verify that all the main tray paper path Replace the Go to Step 2.
sensor wires are clear of the take away wiring harness.
rollers.
2. Are any wires damaged?

2 1. Are the take away rollers dirty, contaminated, Replace the Go to Step 3.
or damaged? take away roller.

3 1. Run the Paper Path Drive test. Go to Step 5. Go to Step 4.

2. Did the test pass?

4 1. Does the media path motor run extremely The media path Go to Step 5.
fast? motor encoder
is faulty; replace
the motor.

5 1. Remove the media drive gearbox and Complete. If the media

manually rotate each paper path roller. path is clear of
2. Identify any roller that may be binding and debris and the
causing drag on the printer. rollers rotate
normally,
3. Repair or replace as necessary.
replace the
4. Did this correct the problem? media gearbox.

Service Manual 3-37

31,0XX.6x Errors - Program Faults
a. Reset NVRAM, and then retest.
b. Ensure ground integrity for the printer (see "Ensuring Ground Integrity" on
page 4-77).

3-38 Phaser 8400/8500/8550 Color Printer

33,0XX.xx Errors - Tray Manager Device Faults
33,001.42: Tray 1 width value too low.
33,002.43: Tray 1 width value too high.
Troubleshooting Procedure for Tray 1

Step Questions and Actions Yes No

1 1. Check the wiring and connectors from the Go to Step 2. Replace the
front door to the I/O board. wiring harness.
2. Are the wires connected properly?

2 1. Run the Test Tray 1 Width Sensor test. Replace the I/O Replace the
2. Did the test pass? board. front door.

34,0XX.xx Errors - Printhead NVRAM Faults

34,001.43: An error occurred while attempting read/write access to the printhead
calibration partition in NVRAM. The printhead cable may be unplugged.
34,002.44: An error occurred while attempting read/write access to the printhead ink
data partition in NVRAM.
34,003.45: An error occurred while attempting read/write access to the printhead
data partition in NVRAM.
34,004.46: An error occurred while accessing the printhead NVRAM hardware for
the purpose of initialization. The printhead cable may be unplugged.
Troubleshooting Procedure for Printhead NVRAM

Step Questions and Actions Yes No

1 1. Check and reseat all wiring to the printhead. Complete. Replace in the
2. Did this correct the problem? following order:
■Printhead
■Electronics
Module

Service Manual 3-39

36,000.40 Errors - Drum Maintenance Faults
Troubleshooting Procedure for Drum Maintenance

Step Questions and Actions Yes No

1 1. Ensure ground integrity (see "Ensuring Complete. Go to Step 2.

Ground Integrity" on page 4-77).
2. Did this correct the problem?

2 1. Ensure the process drive system is correctly Complete. Go to Step 3.

homed as described in "Homing the Process
Gear Drive Train" on page 6-8.

3 1. Inspect pivot plate for cracks. Complete. Go to Step 4.

2. Check the drum maintenance cam rollers for
damage or improper movement.
3. If the pivot plate or cam rollers are faulty,
replace.
4. Did this correct the problem?

4 1. Use service diagnostics to run the Drum If either test fails, replace the
Maintenance/Transfix Home test. process drive.
2. Use service diagnostics to run the Drum
Maintenance Drive test.

36,001.67 Errors
a. Replace the pivot plate.
b. Replace the drum maintenance unit.

36,002.44 Errors
Printer can’t write to Drum Maintenance Unit.
a. Ensure the DMU sits correctly in the pivot plate.
b. Replace the DMU.
c. Replace the drum maintenance pivot plate assembly.

3-40 Phaser 8400/8500/8550 Color Printer

37,0XX.xx Errors - PEST Faults
AC power supplied by power sources such as uninterruptible power supplies (UPS’s)
or DC-to-AC inverter systems, may not supply enough current to properly power up
the printer. In these cases, the printer may report printhead jet-stack or reservoir
heater disconnect, drum heater, or preheater errors (37,002.47 thru 37,012.48). Verify
the AC power source prior to troubleshooting a printer exhibiting any of these errors.
For wiring diagrams to aid in diagnosing PEST faults, see "Wiring Diagrams" on
page 10-1.

8400/8500/8550 PEST Description

37,001.46: Generic PEST error. Something went wrong during the PEST process.
37,002.47: PEST Error - Printhead Left jetstack disconnect. The left jetstack is not
drawing the expected power from the supply.

37,03.48: PEST - Printhead Right jetstack disconnect. The right jetstack is not
drawing the expected power from the supply.

37,004.40: PEST - Printhead Reservoir 0 disconnect. Reservoir 0 is not drawing the

expected power from the supply.

37,005.41: PEST - Printhead Reservoir 1 disconnect. Reservoir 1 is not drawing the

expected power from the supply.

37,006.42: PEST - Drum disconnect. The drum heater is not drawing the expected
power from the supply.

37,008.44: PEST - Preheater disconnect. The preheater is not drawing the expected
power from the supply.

8400 PEST Description 8500/8550 PEST description

37,009.45: Inkmelt 0 (Yellow) disconnect. All ink melters are disconnected. All ink
The inkmelt heater is not drawing melters are not drawing the expected
the expected power from the power. Check to see if the ink melter’s
supply. AC cable is connected.

37,010.46: Inkmelt 1 (Cyan) disconnect. The Inkmelt 0 (Yellow) disconnect. The

inkmelt heater is not drawing the inkmelt heater is not drawing the
expected power from the supply. expected power from the supply.

37,011.44: Inkmelt 2 (Magenta) disconnect. Inkmelt 1 (Cyan) disconnect. The

The inkmelt heater is not drawing inkmelt heater is not drawing the
the expected power from the expected power from the supply.
supply.

37,012.48: Inkmelt 3 (Black) disconnect. The Inkmelt 2 (Magenta) disconnect. The

inkmelt heater is not drawing the inkmelt heater is not drawing the
expected power from the supply. expected power from the supply.

37,013.40: Inkmelt 3 (Black) disconnect. The

inkmelt heater is not drawing the
expected power from the supply.

Service Manual 3-41

Troubleshooting Procedure for Heaters

Step Questions and Actions Yes No

1 1. Check the wiring running from the problem Replace the Go to Step 2.
component to the printhead. problem wiring
2. Is the wiring damaged or not working harness.
properly?

2 1. Run the appropriate diagnostic test: Replace the

37,002.47 = Left Jetstack Heater Printhead.
37,003.48 = Right Jetstack Heater
37,004.40, 37,005.41 = Reservoir Heaters
2. Did the test pass?

3 1. Run the appropriate diagnostic test: Replace the

37,006.42 = Drum Heater Preheater
Drum
2. Did the test pass?
Assembly.

4 1. Run the appropriate diagnostic test: Replace the

37,008.44 = Preheat Heater Preheater.
2. Did the test pass?

5 1. Run the appropriate diagnostic test: Replace the Ink

37,009.45 = (8500/8550) All ink melters loader.
= (8400) Ink Melt 1
37,010.46 = (8500/8550) Ink Melt 1
= (8400) Ink Melt 2
37,011.47 = (8500/8550) Ink Melt 2
= (8400) Ink Melt 3
37,012.48 = (8500/8550) Ink Melt 3
= (8400) Ink Melt 4
37,013.48 = (8500/8550) Ink Melt 4
2. Did the test pass?

3-42 Phaser 8400/8500/8550 Color Printer

 8400 PEST Description 8500/8550 PEST description

37,013.40: Electronics module cooling fan

disconnect. The electronics
cooling fan is not drawing the
expected power from the supply.

37,014.41: Drum cooling fan disconnect. Electronics Cooling Fan Disconnect.

The drum cooling fan is not drawing The Electronics Cooling Fan is not
the expected power from the supply. drawing the expected power from the
supply.

37,015.42: Drum cooling fan disconnect. The

drum cooling fan is not drawing the
expected power from the supply.

Troubleshooting Procedure for Fans

Step Questions and Actions Yes No

1 1. Run the appropriate diagnostic test: Go to Step 2. Go to Step 2.

37,013.40 = (8400) Elect. Cooling
37,014.40 = (8500/8550) Elect. Cooling
37,014.41 = (8400) Drum Fan
37,015.41 = (8500/8550) Drum Fan
2. Did the test pass?

2 1. Check the wiring for the problem fan. Replace the Replace the
2. Is the wiring damaged or not working problem wiring problem
properly? harness. component:
■ Electronics
cooling fan
■ Drum Fan

Service Manual 3-43

 8400 PEST Description 8500/8550 PEST description

37,016.43: PEST 50 V power supply test. For 50 V power supply test. The power
Phaser 8400 printers, the 50 V supply is loaded with the head
power supply is loaded with the maintenance, the deskew, and the pick
Head Maintenance clutch, and then clutches.
tested.
Check the 50 V on the Power supply. Or,
ensure that the cables are not plugged
into any of the clutches.

The expected power from the supply is

not being drawn. This error may be
caused by a power supply that is faulty
or shorted by some other 50 V device.

Check the 50 V on the Power supply. Or,

ensure that the cables are not plugged
into the clutch.

50V Power Supply Fault Troubleshooting Procedure

Step Questions and Actions Yes No

1 Check for a short in the electronics module. Go to Step 2. Go to Step 2.

NOTE: Damage to circuits within the electronics
module may occur if the power supply
capacitors are not allowed to fully
discharge.
NOTE: It is possible that the power supply is not
shorted, but instead is out of spec and
can lead to an error condition.
1. Measure the 50 V power supply output. The
test point is located on the power control
board below the main board RAM DIMMs.
2. Is the power supply within specification?
3. Turn off the printer and wait 30 seconds for
the power supply capacitors to discharge.

3-44 Phaser 8400/8500/8550 Color Printer

50V Power Supply Fault Troubleshooting Procedure (Continued)

Step Questions and Actions Yes No

2 1. Unplug the following electronics module Go to Step 3. Replace the

connectors. This step disconnects all other electronics
external circuits so the electronics module module.
can be tested alone:
■ Power Control to I/O board (J800 - gray
ribbon cable on right side)
■ Power Control right (J400 – 16 wire,
multi-color)
■ Printhead data interface (J130 – gray
ribbon cable on top side)
■ Wave amp signal (J790) short gray
ribbon cable located on left side)
■ Printhead power connector
■ Power Control left (J390 – 34 wire,
multi-color)
■ Y-Axis motor (J280)
2. Turn on power to the printer.
3. Do the PE and PS indicators (near the power
switch) flash momentarily?

3 1. Turn off the printer and wait 30 seconds for Go to Step 4. Go to Step 5.
power supply capacitors to discharge.
2. Plug in the power control to I/O board
connector (J800).
3. Turn on power to the printer.
4. Do the PE and PS indicators flash
momentarily?

4 1. If the 50V Power Supply LED (viewed thru the cooling grill below the power cord
receptacle) illuminates, the short is on one of the external devices you unplugged
earlier. In this case, systematically turn off the printer, plug a wiring harness back
in, and turn the printer on until the 50V supply fails (see “Measuring DC Power
Supply Voltages” on page 76).
2. Replace the defective part. Retest the printer.

5 1. To isolate the problem to the I/O board or its Replace the I/O Go to Step 6.
related cabling, unplug the I/O board board.
connectors.
■ Umbilical Right J1
■ Waste Tray Sense J110
■ Stripper Solenoid J250
■ Paper Tray Sense J610 Ink load Signal
J910
■ DMU Sense J860
■ Drum Thermistor J870
■ Exit Module J680
■ Heater Relay Control J950
2. Test the resistance of the I/O board to Pin1
of J270.
3. Is the resistance still less than 1K ohm?

Service Manual 3-45

50V Power Supply Fault Troubleshooting Procedure (Continued)

Step Questions and Actions Yes No

6 1. Plug in the I/O board connectors one at a Leave power on Go to Step 7.

time and retest the resistance. to ensure the
2. Replace components until you find one that problem is fixed.
creates a short at J270, Pin 1.
3. Find any shorted components?

7 1. Connect the wave Amp. Leave power on Go to Step 8.

2. Any problems. to ensure the
problem is fixed.

8 1. Connect printhead. Power up printer and retest.

3-46 Phaser 8400/8500/8550 Color Printer

 8400 PEST Description 8500/8550 PEST description

37,017.44: Head maintenance clutch Head Maintenance Clutch

disconnect. The main tray deskew Disconnect. The Head Maintenance
clutch is not drawing the expected Clutch is not drawing the expected
power from the supply. power from the supply.

37,018.45: Main tray (Tray 1) deskew clutch Main Tray Deskew Clutch Disconnect.
disconnect. The main tray pick The Main Tray Deskew Clutch is not
clutch is not drawing the expected drawing the expected power from the
power from the supply. supply.

37,019.46: Tray 1 pick solenoid disconnect. Main Tray Pick Clutch Disconnect.
The tray 1 pick solenoid is not The Main Tray Pick Clutch is not drawing
drawing the expected power from the expected power from the supply.
the supply.

37,020.47: Strip solenoid disconnect. The Multipurpose Tray Pick Solenoid

strip solenoid is not drawing the Disconnect. The Multipurpose Tray
expected power from the supply. Pick Solenoid is not drawing the
expected power from the supply.

37,021.48: Strip solenoid disconnect. The strip

solenoid is not drawing the expected
power from the supply.

37,022.40: Preheat Solenoid Disconnect. The

Preheat Solenoid is not drawing the
expected power from the supply.

37,023.41: Head Tilt Solenoid Disconnect. The

Head Tilt Solenoid is not drawing the
expected power from the supply.

Service Manual 3-47

Solenoid, Clutch and Pick Troubleshooting Procedure

Step Questions and Actions Yes No

1 1. Run the appropriate diagnostic test: Go to Step 3. Go to Step 2.

■ 37,017.44 = Head Maintenance Clutch
■ 37,018.45 = Deskew Clutch
■ 37,019.46 = (8500/8550) Main tray
pick Clutch
■ 37,019.46 =(8400) Pick Solenoid
■ 37,020.47 = (8500/8550) Multipurpose
Pick Solenoid
■ 37,020.47 = (8400) Strip Solenoid
■ 37,021.48 = (8500/8550) Strip
Solenoid
■ 37,022.40 = (8400) Preheat Solenoid
■ 37,023.41 = (8500/8550) Head Tilt
Solenoid
2. Did the test pass?

2 1. Check the wiring for the problem clutch or Replace the Replace the
solenoid. problem wiring problem
2. Is the wiring damaged or not working harness. component:
properly? ■ Head
maintenance
clutch
■ Media path
drive assembly
■ Pick solenoid
■ Strip
solenoid
■ Head tilt
solenoid
■ Preheater
solenoid

8400 8500/8550 PEST Description

37,021.48: 37,024.48: Tray 1 elevator disconnect. The main tray elevator is not
drawing the expected power from the supply.

Troubleshooting Procedure for Tray 1 Elevator

Step Questions and Actions Yes No

1 1. Run the Tray 2 Lift Motor test. Replace the Go to Step 2.

2. Did the test pass? electronics
module.

2 1. Check the wiring to the tray 2 lift motor. Replace the Replace the
2. Is the wiring damaged? wiring harness tray lift motor.

3-48 Phaser 8400/8500/8550 Color Printer

 8400 8500/8550 8400 PEST Description

37,022.40: 37,025.43: Pressure pump motor disconnect. The pressure pump

motor is not drawing the expected power from the supply.

Troubleshooting Procedure for Pressure Pump

Step Questions and Actions Yes No

1 1. Run the Pressure Pump Motor test. Replace the Go to Step 2.

2. Did the test pass? electronics
module.

2 1. Check the purge pump assembly wiring. Replace the pressure pump motor.
2. Is the wiring damaged?

8400 8500/8550 PEST Description

37,023.41: 37,026.44 Purge valve disconnect. The purge valve is not drawing the
expected power from the supply.

Troubleshooting Procedure for Purge Valve

Step Questions and Actions Yes No

1 1. Run the Purge Vent Solenoid test. Go to Step 2. Replace the

2. Did the test pass? purge pump.

2 1. Check the purge pump assembly wiring. Replace the defective wiring or the
2. Is the wiring damaged? purge pump.

Service Manual 3-49

 8400 8500/8550 PEST Description

37,024.42: 37,027.45: Drum heater relay board disconnect. Both drum heater
relay coils are not drawing the expected power from the
supply.

37,025.43: 37,028.46: Drum heater relay A disconnect. The drum heater A coil is
not drawing the expected power from the supply.

37,026.44: 37,029.47: Drum heater relay B disconnect. The drum heater B coil is
not drawing the expected power from the supply.

Troubleshooting Procedures for Relay Board

Step Questions and Actions Yes No

1 1. Run the Drum Heater Relay test. Replace the Go to Step 2.

2. Did the test pass? electronics
module.

2 1. Check the wiring for damage. Replace the drum heater relay
board.

8400 8500/8550 PEST Description

37,027.45: 37,030.48: X-axis motor disconnect. The X-axis motor is not drawing
the expected power from the supply (both phases).

37,028.46: 37,031.40: X-axis motor disconnect. The X-axis motor (first phase) is
not drawing the expected power from the supply

37,029.47: 37,032.41: X-axis motor short. The X-axis motor is drawing too much
power from the supply (first phase).

37,030.48: 37,033.42: X-axis motor disconnect. The X-axis motor (second phase)
is not drawing the expected power from the supply.

37,031.40: 37,034.43: X-axis motor short. The X-axis motor is drawing too much
power from the supply (second phase).

Troubleshooting Procedure for X-axis Motor

Step Questions and Actions Yes No

1 1. Run the X-axis Drive test. Replace the Go to Step 2.

2. Did the test pass? electronics
module.

2 1. Check the X- axis motor wiring for damage. Replace the X-axis motor.

3-50 Phaser 8400/8500/8550 Color Printer

 8400 8500/8550 PEST Description

37,032.41: 37,035.44: Y-axis motor disconnect. The Y-axis motor is not drawing
the expected power from the supply.

37,033.42: 37,036.45: Y-axis motor short. The Y-axis motor is drawing too much
power from the supply.

Troubleshooting Procedure for Y-axis Motor

Step Questions and Actions Yes No

1 1. Remove any obstructions interfering with Complete. Go to Step 2.

drum rotation.
2. Inspect the drum and ensure the drum
rotates smoothly, if not replace the drum and
retest.
3. Did this correct the problem?

2 1. Disconnect the Y-axis belt. Go to Step 3. Replace the

2. Does the Y-motor shaft rotate smoothly? Y-axis motor.

3 1. Reconnect the Y-axis belt. Replace the Go to Step 4.

2. Run the Y-axis Motor test. electronics
module.
3. Did the test pass?

4 1. Check the wiring for damage. Replace the Y-axis motor.

8400 8500/8550 PEST Description

37,034.43: 37,037.46: Media path motor disconnect. The media path motor is not
drawing the expected power from the supply.

37,035.44: 37,038.47: Media path motor short. The media path motor is drawing
too much power from the supply.

Troubleshooting Procedure for Media Path Motor

Step Questions and Actions Yes No

1 1. Run the Media Path Motor test. Replace the Go to Step 2.

2. Did the test pass? electronics
module.

2 1. Check the wiring for damage. Replace the media path motor.

Service Manual 3-51

 8400 8500/8550 PEST Description

37,036.45: 37,039.48: Process motor disconnect. The process motor is not

drawing the expected power from the supply.

37,037.46: 37,040.40: Process motor short. The process motor is drawing too
much power from the supply.

Troubleshooting Procedure for Process Motor

Step Questions and Actions Yes No

1 1. Do the process drive gears, transfix shaft, Go to Step 2. Look for drag in
and drum maintenance shafts rotate freely? the rollers or
replace the
process drive.

2 1. Run the Process Motor test. Replace the Go to Step 3.

2. Did the test pass? electronics
module.

3 1. Check the wiring for damage. Replace the process drive

assembly.

8400 PEST Description 8500/8550 PEST description

37,038.47: The power supply did not reset

properly as requested. The reset line
may not be connected.

37,039.48: Power supply +5 volt over limit.

37,040.40: Power supply +5 volt under limit.
37,041.41: Power supply +1.8 volt over limit. The power supply did not reset
properly as requested. The reset line
may not be connected.

37,042.42: Power supply +1.8 volt under limit.

37,043.43: Power supply +2.5 volt over limit. Power supply +2.5 volt over limit.

37,044.44: Power supply +2.5 volt under limit. Power supply +2.5 volt under limit.

37,045.45: Power supply +3.3 volt over limit. Power supply +3.3 volt over limit.

37,046.46: Power supply +3.3 volt under limit. Power supply +3.3 volt under limit.

37,047.47: Power supply +12 volt over limit. Power supply +12 volt over limit

37,048.48: Power supply +12 volt under limit Power supply +12 volt under limit

3-52 Phaser 8400/8500/8550 Color Printer

 8400 PEST Description 8500/8550 PEST description

37,049.40: Power supply -12 volt over limit. Power supply -12 volt over limit.

37,050.41: Power supply -12 volt under limit. Power supply -12 volt under limit.

37,051.42: Power supply current over limit. Power supply current over limit.

37,052.43: Power supply current under limit. Power supply current under limit.

37,053.44: Power supply +50 volt over limit. Power supply +50 volt over limit.

37,054.45: Power supply +50 volt under limit. Power supply +50 volt under limit.

37,055.46: Power supply -50 volt over limit. Power supply -50 volt over limit.

37,056.47: Power supply -50 volt under limit. Power supply -50 volt under limit.

37,057.48: Power supply +15 volt over limit. Power supply +15 volt over limit.

37,058.40: Power supply +15 volt under limit. Power supply +15 volt under limit.

37,059.41: Power supply -15 volt over limit. Power supply -15 volt over limit.

37,060.42: Power supply -15 volt under limit. Power supply -15 volt under limit.

37,061.43: Power supply high switch will not Power supply +5 volt over limit.
activate. 12, 15, and 50 volt missing.
This may be due to a short or
disconnected power supply reset line.

37,062.44: Vss measurement too low. The Power supply +5 volt under limit.
printhead power cable may be
disconnected.

37,063.45: Vpp measurement too low. The Power supply high switch will not
printhead power cable may be activate. 12, 15, and 50 volt missing.
disconnected. This may be due to a short or
disconnected power supply reset line.

37,064.46: Vss measurement too low. The

printhead power cable may be
disconnected.

37,065.47: Vpp measurement too low, head

power cable may be disconnected.
Wave amp drive cable may be
damaged or disconnected at head
driver board or wave amp board.

37,066.48: The wave amp appears to be

shorted. It is drawing to much power.
Check for bad wave amp drive cable
(lifted ends of conductors).

Service Manual 3-53

Troubleshooting Procedure for Power Supply

Step Questions and Actions Yes No

1 1. Run the Voltages check test. Go to Step 2. Replace the

2. Did the test pass? electronics
module.

2 1. Check the printhead power cable. Reseat or Replace the

2. Is the wiring damaged or not connected? replace the wave amp.
wiring.

3-54 Phaser 8400/8500/8550 Color Printer

Jam Codes
The printer stores the most recent 20 events in Jam History. To access this information
for Phaser 8400 printers, press the Up Arrow button when the jam code displays.
Then, scroll to Jam History and press OK to display the most recent jam list.
Phaser 8500/8550 printers have improved jam code reporting capabilities. When the
printer is in a jam condition, pressing HELP displays the jam code. The jam code
contains 4-digits compared to the 3-digit codes produced by Phaser 8400 printers. The
fourth digit simplifies troubleshooting by indicating one of the following:
■ The tray number at which the jam occurred (1, 2, 3, or 4).
■ The jam occurred while processing a chase page (5).

Service Manual 3-55

 ■ The jam occurred when generating a duplex print (6).

Jam Code Key Table

Process Event Process Event Basis for Printer (8500/8550

8400 8500/8550 Jam State only)

A Deskew Flag A Deskew Flag 2 Sensor A Printer 1st 1 - Tray 1

B Preheat Flag B Preheat Flag Event Init - 2 - Tray 2
C Strip Flag C Strip Flag 3 Timeout Abnormal 3 - Tray 3
D Exit Flag D Exit Flag 4 Motor Stall Shutdown 4 - Tray 4
5 Motor B Printer 1st 5 - Chase
E Tray 1 Width E Tray 1 Media Position Init - Normal page
Sensor Present 6 Length Short Shutdown 6 - Duplex
7 Length Long C Mechanical
F Front Door F Front Door Recovery
Event Event D Warmup
E Ready
G Tray 2 Media G Exit Door F Fault
Sensor H Tray 2 Media G Auto Drum
H Tray 3 Media Sensor Maintenance
Sensor J Tray 3 Media H Printhead
J Tray 4 Media Sensor Maintenance
Sensor J Printhead
K Tray 4 Media M Paper Path Purge
Sensor Motor K Oil Transfix
N Y-Axis Motor Roller
M Paper Path P Process Motor L Standby
Motor Q DMU Missing
N Y-Axis Motor Print
P Process Motor T Exit Door Event Process
U Pipeline Substates
T Exit Door Event Resource M Pick from
Tray 2
V Tray 2 Event V Tray 2 Event N Pick from
W Tray 3 Event W Tray 3 Event Tray 3
X Tray 3 Pick Flag X Tray 3 Pick Flag P Pick from
Y Tray 4 Event Y Tray 4 Event Tray 4
Z Tray 4 Pick Flag Z Tray 4 Pick Flag Q Pick from
Tray 1
R Pick from
Duplex

S Stage for
Transfix
T Transfix

V Print Drum
Maintenance
W Imaging
X Exit
Z Shutdown

3-56 Phaser 8400/8500/8550 Color Printer

Jam Code Definition Table
Not all jam code combinations are documented in this manual, only the codes that
occur most commonly.

Note
The following table only shows the 3-digit jam code. For Phaser 8500/8550
Printers, an additional 4th digit represents the tray number (5 represents a chase
page and 6 represents duplex). Numbers following the 4th digit represent the
page number:

Jam Code Troubleshooting Procedures

A2C Deskew sensor in unexpected state during mechanical recovery.

1. Check the drum maintenance unit NVRAM contacts during the oiling process for
continuity.
2. Instruct customer to remove media from Tray 1 before opening the front door.
3. Replace the pivot arm.

A2E Deskew sensor in unexpected state at ready.

1. Ensure ground integrity of the printer, see page 4-77.

2. Replace Tray 1 solenoid.

A2F Deskew sensor in unexpected state.

1. Ensure ground integrity of the printer, see page 4-77.

2. Verify all doors and covers are fully closed and not moving during printing.

A2J Deskew flag sensor event during head purge.

A2K Deskew sensor in an unexpected state during a transfix roller oiling.

A2M The deskew flag tripped unexpectedly while the printer was picking paper from
Tray 2.

A2N The deskew flag tripped unexpectedly while the printer was picking paper from
Tray 3.

A2P The deskew flag tripped unexpectedly while the printer was picking paper from
Tray 4.

A2S Deskew sensor in unexpected state during media stage for transfix.

Service Manual 3-57

Jam Code Troubleshooting Procedures (Continued)
A2Q The deskew flag tripped unexpectedly while the printer was picking paper from
Tray 1.

1. Try using different, supported media.

2. Ensure the paper guides are snug against the media in the tray.
3. Push up on Tray {2 - 4} Nudger Roller until it is captured by actuator arm.
4. Run the following diagnostic tests, Deskew Flag, Tray {2-4} Pick Clutch and the
Tray {2-4} Solenoid.
5. Ensure ground integrity of the printer, see page 4-77.
6. Verify all doors and covers are fully closed and not moving during printing.
7. Replace the Tray {2 - 4} Pick Clutch.
8. Replace the retard roller.
9. Replace the preheater.

A3G
Deskew Sensor time-out event during an auto drum maintenance cycle.
A3M
The deskew flag timed out waiting for the paper picked from Tray 2.
A3N
The deskew flag timed out waiting for the paper picked from Tray 3
A3P
The deskew flag timed out waiting for the paper picked from Tray 4.
A3Q
The deskew flag timed out waiting for the paper picked from Tray 1.

1. Verify media is appropriate for the tray.

2. Verify the tray is not overfilled and the guides are positioned correctly.
3. Check for obstructions in the paper path.
4. Test the appropriate Tray Solenoid.
5. Test the appropriate Tray Pick Clutch.
6. Ensure the take away rollers are in good condition.
7. Test the take away roller using the diagnostic Paper Path Drive test.
8. Replace the appropriate Separator Pad Assembly.
9. Replace the Pick Assembly.

A3R Deskew sensor time-out during movement from exit roller to deskew roller when
duplexing print.

1. Ensure the media is appropriate for two-sided printing. Not too short, not too
smooth. Check printer specifications.
2. Inspect the condition of the exit rollers and the duplex roller.
3. Check the Front Door for obstructions or damage, replace the Front Door if
necessary.
4. Test the operation of the exit roller and the duplex roller using diagnostic Duplex
Paper Lead Edge Times test.
5. Test the deskew sensor using the diagnostic Sensors test.

3-58 Phaser 8400/8500/8550 Color Printer

Jam Code Troubleshooting Procedures (Continued)
B2C Preheat exit sensor unexpected state during mechanical recovery.

1. Clear jam and let printer finish mechanical recovery.

2. Ensure ground integrity of the printer, see page 4-77.

B2F Preheater exit sensor in unexpected state during fault.

B2S Preheater exit sensor in unexpected state during stage.

1. Ensure ground integrity of the printer, see page 4-77.

2. Check the drum maintenance unit NVRAM contacts during the oiling process for
continuity.
3. Check the waste tray.
4. Replace the preheater assembly.

B2M The preheat flag tripped unexpectedly while the printer was picking paper from
Tray 2.

B2N The preheat flag tripped unexpectedly while the printer was picking paper from
Tray 3.

B2P The preheat flag tripped unexpectedly while the printer was picking paper from
Tray 4.

B2Q The preheat flag tripped unexpectedly while the printer was picking paper from
Tray 1.

1. Test the preheat flag using the diagnostic Sensors test.

2. Ensure ground integrity of the printer, see page 4-77.

B3M The preheat flag timed out waiting for the paper picked from Tray 2.

B3N The preheat flag timed out waiting for the paper picked from Tray 3.

B3P The preheat flag timed out waiting for the paper picked from Tray 4

B3Q The preheat flag timed out waiting for the paper picked from Tray 1.

B3S Preheater sensor timed out during stage.

B3T Preheater exit sensor timed out during transfix.

1. Verify the media is appropriate for the tray.

2. Check for paper path obstructions, ensure the preheater plate moves freely.
3. Replace the Tray 1 Separator Pad Assembly.
4. Run diagnostics to test the preheat flag.
5. Ensure the deskew rollers are in good condition.
6. Run the Deskew Clutch test.
7. Run the Paper Path Drive test.
8. Replace the preheater, then retest

Service Manual 3-59

Jam Code Troubleshooting Procedures (Continued)
C2C Strip flag unexpected event during mechanical recovery.

C2D Strip flag unexpected state during warm-up.

C2E Strip flag unexpected event during printer ready.

C2F Strip flag unexpected event during fault.

C2K Strip flag unexpected event during transfix roller oiling.

C2M The strip flag actuated unexpectedly when paper picked from Tray 2.

C2N The strip flag actuated unexpectedly when paper picked from Tray 3.

C2P The strip flag actuated unexpectedly when paper picked from Tray 4.

C2Q The strip flag actuated unexpectedly when paper picked from Tray 1.

C2R Strip flag unexpected event during pick from the duplex path.

C2T Strip flag unexpected event during transfix.

1. Ensure ground integrity of the printer, see page 4-77.

2. Check the paper tray for overfill.
3. Run the Stripper sensor test.
4. Inspect the stripper blade for damage or debris.
5. Run the Paper Lead Edge Times test.
6. Replace the stripper carriage assembly.

C2X Strip flag unexpected event during exit.

1. Ensure the media is not too thick and that it is supported by the printer.
2. Use a less glossy media.
3. Ensure the guides in the tray are snug against the media.
4. If the drum maintenance unit is near the end of its life, replace it.
5. Clean and inspect the exit rollers.
6. Run the Paper Path Drive test.

C3M The strip flag timed out waiting for the paper picked from Tray 2.

C3N The strip flag timed out waiting for the paper picked from Tray 3.

C3P The strip flag timed out waiting for the paper picked from Tray 4.

C3Q The strip flag timed out waiting for the paper picked from Tray 1.

3-60 Phaser 8400/8500/8550 Color Printer

Jam Code Troubleshooting Procedures (Continued)
C3T Strip flag time-out during transfix.

1. Ensure media is correct size and type for the tray. If envelope jam, try a different
style.
2. Check the drum maintenance unit for proper operation, replace if necessary.
3. Ensure the process drive assembly is correctly homed, see page 6-8.
4. Ensure the stripper carriage moves freely, run the Stripper Contact test.
5. Run the Transfix Drive Slow and Transfix Drive Fast tests.

C3X Strip flag time-out during exit.

1. Open the exit cover and ensure the springs for the idler rollers are present and
installed correctly (they should be the same for all 5 rollers).
2. Verify the metal bar is installed on top of the exit guide.

C5X Print pulled back into transfix nip during exit.

1. Ensure the media is not too thick and that it is supported by the printer.
2. Use a less glossy media.
3. If the drum maintenance unit is near the end of its life, replace it.
4. Clean and inspect the exit rollers.
5. Ensure the process drive is correctly homed.
6. Run the Paper Path Drive test.
7. Replace the lower exit guide assembly.

D2D Exit flag unexpected event during warm-up.

D2M The exit flag actuated unexpectedly when paper picked from Tray 2.

D2N The exit flag actuated unexpectedly when paper picked from Tray 3.

D2P The exit flag actuated unexpectedly when paper picked from Tray 4.

D2Q The exit flag actuated unexpectedly when paper picked from Tray 1.

D2R The exit flag actuated unexpectedly when duplexing.

D2T The exit flag actuated unexpectedly when transfixing.

1. Ensure ground integrity of the printer, see page 4-77.

2. Run the Sensors test to test the exit sensor.
3. Run the Paper Lead Edge Times test.
4. Replace problem component.

Service Manual 3-61

Jam Code Troubleshooting Procedures (Continued)
D2X The exit flag actuated unexpectedly exit.

1. Ensure the media is not too thick and that it is supported by the printer.
2. Use a less glossy media.
3. If the drum maintenance unit is near the end of its life, replace it.
4. Clean and inspect the exit rollers.
5. Check the exit flag for proper installation or damage, replace the flag if
necessary.
6. Run the diagnostic Paper Path Drive test.
7. Replace problem component.

D3C Exit flag time-out during mechanical recovery.

D3M Exit flag timed out following Tray 2 Pick.

D3N Exit flag timed out following Tray 3 Pick.

D3P Exit flag timed out following Tray 4 Pick.

D3Q Exit flag timed out following Tray 1 Pick.

D3R Exit flag timed out during duplexing.

D3T Exit flag time-out during transfix.

1. Inspect the exit path for obstructions.

2. Inspect and clean the exit roller, ensure the exit roller rotates.
3. Inspect and clean the stripper blade.
4. Replace the drum maintenance unit.
5. Run the diagnostic Paper Path Drive test.

E2D Tray 1 width sensor during warm-up.

E2E Tray 1 width sensor during

E2Q Tray 1 width sensor during Tray 1 pick.

1. Examine the Tray 1 width guides for proper movement and ensure the side
guides are not being adjusted while printing.
2. Ensure the front door is closed and the wiring is properly connected and seated.
3. Run the Tray 1 sensor test.
4. Inspect the Tray 1 wiring to the I/O board.
5. Replace the I/O board, then retest.

3-62 Phaser 8400/8500/8550 Color Printer

Jam Code Troubleshooting Procedures (Continued)
F2D The front door open flag unexpectedly tripped while the printer was warming up.

F2F The front door open flag unexpectedly tripped while the printer was in a fault state.

F2M The front door open flag unexpectedly tripped when the printer pick from Tray 2.

F2N The front door open flag unexpectedly tripped when the printer pick from Tray 3.

F2P The front door open flag unexpectedly tripped when the printer pick from Tray 4.

F2Q The front door open flag unexpectedly tripped when the printer pick from Tray 1.

F2R The front door open flag unexpectedly tripped while the printer was duplexing.

F2S Front door sensor unexpectedly actuated while the paper was staged for transfix.

F2T The front door open flag unexpectedly tripped while the print was being transfixed.

F2V The front door open flag unexpectedly tripped while the printer was oiling the drum
during a print job.

F2W The front door open flag unexpectedly tripped while the printer was imaging during
a print job.

F2X Front door sensor unexpectedly actuated during exit.

1. Ensure the media is supported.

2. Ensure ground integrity of the printer, see page 4-77.
3. Run the diagnostic Sensors test to test the door sensor.
4. Check that the doors and covers are properly closed and seated.
5. Run the door sensor test.

G2M Tray 2 removed during pick from Tray 2.

H2N Tray 3 was removed during pick from Tray 3.

J2M Tray 4 was removed during pick from Tray 4.

J2P Tray 4 Media Present Sensor event pick from Tray 4.

M2C Media path motor had an unexpected event during mechanical recovery.

M4A Paper path motor stalled during an abnormal printer shutdown.

M4B Paper path motor stalled during a normal printer shutdown.

M4C Paper path motor stalled during mechanical recovery.

M4D Paper path motor stalled during printer warm-up.

M4E Paper path motor stalled while the printer was in its ready state.

M4F Paper path motor stalled while the printer was in a fault state.

M4G Paper path motor stalled while the printer performed an auto drum maintenance
cycle.

Service Manual 3-63

Jam Code Troubleshooting Procedures (Continued)
M4H Paper path motor stalled while the printer performed printhead maintenance.

M4J Paper path motor stalled while the printer performed printhead purge.

M4K Paper path motor stalled while the printer performed an oil transfix roller cycle.

M4L Paper path motor stalled while the printer was in standby mode.

M4M Paper path motor stalled while the printer picked from Tray 2.

M4N Paper path motor stalled while the printer picked from Tray 3.

M4P Paper path motor stalled while the printer picked from Tray 4.

M4Q Paper path motor stalled while the printer picked from Tray 1.

M4R Paper path motor stalled while the printer duplexed the print.

M4S Paper path motor stalled while the printer staged the print for transfix.

M4T Paper path motor stalled during transfix.

1. Verify the media in the tray is supported by the printer.

2. Inspect the paper path for obstructions.
3. Run the Paper Drive Power test.
4. Run the Media Path Motor and Shafts test.
5. Replace the media path drive assembly.

N2T Y-Axis motor event during transfix (Tray 1 only - probably a multi-pick).

1. Verify the media in the tray is supported by the printer.

2. Try a heavier media.
3. Inspect Tray 1 separator pad. Replace if necessary.
4. Send a snippet to turn off the multi-pick detection code.
5. Run the Y-Axis Motor test, replace if necessary.
6. Run the Voltages test, replace the power supply if necessary.

N2W Y-Axis motor event during imaging. Probably a software fault.

1. Ensure ground integrity of the printer, see page 4-77.

N4A Y-Axis motor stalled on power-up following an abnormal printer shutdown.

N4B Y-Axis motor stalled on power-up following a normal printer shutdown.

N4C Y-Axis motor stalled during mechanical recovery.

N4D Y-Axis motor stalled during an printer warm-up.

NFE Y-Axis motor stalled while the printer was in its ready state.

N4F Y-Axis motor stalled while the printer was in a fault state.

N4G Y-Axis motor stalled while the printer performed an auto drum maintenance cycle.

3-64 Phaser 8400/8500/8550 Color Printer

Jam Code Troubleshooting Procedures (Continued)
N4H Y-Axis motor stalled while the printer performed printhead maintenance.

N4J Y-Axis motor stalled while the printer performed printhead purge.

N4K Y-Axis motor stalled while the printer performed an oil transfix roller cycle.

N4L Y-Axis motor stalled while the printer was in standby mode.

N4S Y-Axis motor stalled while the printer staged for transfix.

N4T Y-Axis motor stalled while the printer transfixed the print.

N4V Y-Axis motor stalled while the printer performed a print drum maintenance cycle.

N4W Y-Axis motor stalled while the printer imaged the drum.

N4X Y-Axis motor stalled while the print exited the printer.

1. Check for supported media, generally label, trifold or envelopes cause this error.
2. Try running fewer sheets through the tray.
3. Ensure the Process Drive Gearbox is correctly aligned, refer to "Homing the
Process Gear Drive Train" on page 6-8.
4. Run the Check Y-Axis Motor test, replace if necessary.
5. Run the Belt Slip test.
6. Replace the Tray 1 separator pad assembly.
7. Replace the process drive assembly.

N5T Y-Axis motor out of position while the printer transfixed the print.

N5W Y-Axis motor out of position while the printer imaged the drum.

1. Inspect the Y-Axis drive belt.

2. Run the Check Drum Y-Axis Encoder test.
3. Run the Check Drum Y-Axis Drive test.
4. Run the Check Drum Y-Axis Belt Slip test.
5. Replace the Y-Axis motor or drum assembly if necessary.

N6T Y-Axis motor media short during transfix. The media was measured to be shorter
than it was believed to be.

1. Ensure the media is supported.

2. Ensure ground integrity of the printer, see page 4-77.
3. Run the Check Drum Y-Axis Encoder test.
4. Pull the preheater and check the preheater flag for ink or paper interference.
5. Replace the preheater.

Legal size paper from Tray 4 in standard print mode may buckle. Use slower print
mode.

Service Manual 3-65

Jam Code Troubleshooting Procedures (Continued)
N7T Y-Axis motor media long during transfix. The media was measured to be longer
than it was believed to be.

1. Ensure the media is supported.

2. Try heavier media.
3. Try loading only a few sheets. Some photo media may require running one sheet
at a time.
4. Run the diagnostic Check Drum Y-Axis Encoder test.
5. Replace the Pick Assembly and retard roller.
6. Run the clean ink smears and check the preheater exit flag for debris.
7. Remove the paper preheater and ensure that the exit flag does not interfere with
the assembly. Replace the Paper Preheater if all else checks out.

P4A Process motor stalled on abnormal shutdown.

P4B Process motor stalled on power-up following a normal printer shutdown.

P4C Process motor stalled during mechanical recovery.

P4D Process motor stalled during an printer warm-up.

P4E Process motor stalled while the printer was in its ready state.

P4F Process motor stalled while the printer was in a fault state.

P4G Process motor stalled while the printer performed an auto drum maintenance cycle.

P4H Process motor stalled while the printer performed printhead maintenance.

P4J Process motor stalled while the printer performed printhead purge.

P4K Process motor stalled while the printer performed an oil transfix roller cycle.

P4L Process motor stalled while the printer was in standby mode.

P4S Process motor stalled while the printer staged for transfix.

P4T Process motor stalled while the printer transfixed the print.

P4V Process motor stalled while the printer performed a print drum maintenance cycle.

P4W Process motor stalled while the printer imaged the drum.

P4X Process motor stalled while the print exited the printer.

1. Ensure the media is supported.

2. Verify that the Process Drive Gearbox is correctly aligned and homed.
3. Run the Process Motor test.
4. Replace the process motor if necessary.
5. Run the Transfix Fast and Slow tests.
6. Replace the transfix camshaft and load arms if necessary.
7. Run the Tilt Drive test, replace if necessary.
8. Replace the process drive gearbox assembly.

3-66 Phaser 8400/8500/8550 Color Printer

Jam Code Troubleshooting Procedures (Continued)
T2A The exit door open flag unexpectedly tripped while the printer was performing an
abnormal shutdown.

T2B The exit door open flag unexpectedly tripped while the printer was performing a
normal shutdown.

T2C The exit door open flag unexpectedly tripped while the printer was performing a
mechanical recovery.

T2D The exit door open flag unexpectedly tripped while the printer was warming up.

T2E The exit door open flag unexpectedly tripped while the printer was ready.

T2F The exit door open flag unexpectedly tripped while the printer was in a fault state.

T2G The exit door open flag unexpectedly tripped while the printer was performing an
automatic drum maintenance cycle.

T2H The exit door open flag unexpectedly tripped while the printer was performing a
printhead maintenance cycle.

T2J The exit door open flag unexpectedly tripped while the printer was performing a
printhead purge cycle.

T2K The exit door open flag unexpectedly tripped while the printer was performing a
transfix oiling cycle.

T2L The exit door open flag unexpectedly tripped while the printer was in Standby
mode.

T2M The exit door open flag unexpectedly tripped when the printer picked from Tray 2.

T2N The exit door open flag unexpectedly tripped when the printer picked from Tray 3.

T2P The exit door open flag unexpectedly tripped when the printer picked from Tray 4.

T2Q The exit door open flag unexpectedly tripped when the printer picked from Tray 1.

T2R The exit door open flag unexpectedly tripped while the printer was duplexing.

T2S The exit door open flag unexpectedly tripped while the paper was staging for the
transfix cycle.

T2T The exit door open flag unexpectedly tripped while the print was being transfixed.

T2X The exit door open flag unexpectedly tripped while the printer was ejecting the print.

Service Manual 3-67

Jam Code Troubleshooting Procedures (Continued)
T2Z The exit door open flag unexpectedly tripped while the printer was shutting down.

1. Ensure the media is supported.

2. Ensure ground integrity of the printer, see page 4-77.
3. Run the Monitor Sensors test.
4. Inspect the door switch for damage and proper operation.
5. Check the drum maintenance unit to ensure it is functioning properly and the
blade is not covered with ink debris.
6. Replace the drum maintenance unit.
7. Replace the transfix roller.

V2D Tray 2 media size sensor unexpectedly activated during warm-up.

V2E Tray 2 media size sensor unexpectedly activated during printer ready.

V2F Tray 2 media size sensor unexpectedly activated while printer was in a fault state.

V2K Tray 2 media size sensor unexpected event during oil transfix.

V2L Tray 2 media size sensor unexpectedly activated while the printer was in standby.

V2M Tray 2 media size sensor unexpectedly activated while picking from Tray 2.

V2N Tray 2 media size sensor unexpectedly activated while picking from Tray 3.

V2P Tray 2 media size sensor unexpectedly activated while picking from Tray 4.

V2Q Tray 2 media size sensor unexpectedly activated while picking from Tray 1.

V2R Tray 2 media size sensor unexpectedly activated while duplexing.

V2S Tray 2 media size sensor unexpectedly activated while paper staged for print.

V2T Tray 2 media size sensor unexpectedly activated while transfixing the print.

V2V Tray 2 media size sensor unexpectedly activated while print drum maintenance
cycle was being performed.

V2W Tray 2 media size sensor unexpectedly activated during printer imaging.

V2X Tray 2 media size sensor unexpectedly activated while exiting print.

1. Ensure ground integrity of the printer, see page 4-77.

2. Ensure the Tray 2 paper guides are correctly set.
3. Run the Monitor Sensors test to test the media size sensor.
4. Replace the media size sensor board.
5. Replace the pivot arm.

W2D Tray 3 media size sensor unexpectedly activated during warm-up.

W2E Tray 3 media size sensor unexpectedly activated during printer ready.

W2F Tray 3 media size sensor unexpectedly activated while printer in fault state.

3-68 Phaser 8400/8500/8550 Color Printer

Jam Code Troubleshooting Procedures (Continued)
W2L Tray 3 media size sensor unexpectedly activated while printer in standby.

W2M Tray 3 media size sensor unexpectedly activated while picking from Tray 2.

W2N Tray 3 media size sensor unexpectedly activated while picking from Tray 3.

W2P Tray 3 media size sensor unexpectedly activated while picking from Tray 4.

W2Q Tray 3 media size sensor unexpectedly activated while picking from Tray 1.

W2R Tray 3 media size sensor unexpectedly activated while duplexing.

W2V Tray 3 media size sensor unexpectedly activated while print drum maintenance
cycle being performed.

W2W Tray 3 media size sensor unexpectedly activated during printer imaging.

W2S Tray 3 media size sensor unexpectedly activated while paper staged for print.

W2T Tray 3 media size sensor unexpectedly activated while transfixing the print.

W2X Tray 3 media size sensor unexpectedly activated event while exiting print.

1. Ensure ground integrity of the printer, see page 4-77.

2. Ensure the paper guides are correctly set.
3. Run the Monitor Sensors test to test the media size sensor.
4. Replace the 525-Sheet Feeder.

W4N Tray 3 motor stall during pick from Tray 3.

W4P Tray 3 motor stall during pick from Tray 4.

W4S Tray 3 motor stall during pick from Tray 3.

1. Ensure ground integrity of the printer, see page 4-77.

2. Ensure the paper guides are correctly set.
3. Run the Monitor Sensors test to test the media size sensor.
4. Replace the 525-Sheet Feeder.

X2A Tray 3 pick flag triggered unexpectedly during abnormal shutdown.

X2B Tray 3 pick flag triggered unexpectedly on power-up following normal shutdown.

X2C Tray 3 pick flag triggered unexpectedly during mechanical recovery.

X2D Tray 3 pick flag triggered unexpectedly during warm-up.

X2E Tray 3 pick flag triggered unexpectedly during printer ready.

X2F Tray 3 pick flag triggered unexpectedly while printer was in a fault state.

X2L Tray 3 pick flag triggered unexpectedly while printer in standby.

X2M Tray 3 pick flag triggered unexpectedly while picking from Tray 2.

X2N Tray 3 pick flag triggered unexpectedly while picking from Tray 3.

Service Manual 3-69

Jam Code Troubleshooting Procedures (Continued)
X2P Tray 3 pick flag triggered unexpectedly while picking from Tray 4.

X2Q Tray 3 pick flag triggered unexpectedly while picking from Tray 1.

X2R Tray 3 pick flag triggered unexpectedly while duplexing.

X2S Tray 3 pick flag triggered unexpectedly while transfixing.

X2V Tray 3 pick flag triggered unexpectedly while print drum maintenance cycle was
being performed.

X2W Tray 3 pick flag triggered unexpectedly during printer imaging.

X2X Tray 3 pick flag triggered unexpectedly while exiting print.

1. Ensure ground integrity of the printer, see page 4-77.

2. Ensure the paper guides are correctly set.
3. Run the Monitor Sensors test to test the media size sensor.
4. Replace the 525-Sheet Feeder.
5. Replace the pivot arm.

X3D Tray 3 pick flag sensor timed out during warm-up.

X3E Tray 3 pick flag sensor timed out during wile printer ready.

X3F Tray 3 pick flag sensor timed out while printer in fault state.

X3L Tray 3 pick flag sensor timed out while printer in standby.

X3M Tray 3 pick flag sensor timed out while picking from Tray 2.

X3N Tray 3 pick flag sensor timed out while picking from Tray 3.

X3P Tray 3 pick flag sensor timed out while picking from Tray 4.

X3Q Tray 3 pick flag sensor timed out while picking from Tray 1.

X3R Tray 3 pick flag sensor timed out while duplexing.

X3S Tray 3 pick flag sensor timed out while paper staged for print.

X3T Tray 3 pick flag sensor timed out while transfixing the print.

X3V Tray 3 pick flag sensor timed out while the printer drum maintenance cycle was
being performed.

X3W Tray 3 pick flag sensor timed out while printer imaging.

3-70 Phaser 8400/8500/8550 Color Printer

Jam Code Troubleshooting Procedures (Continued)
X3X Tray 3 pick flag sensor timed out while exiting print.

1. Verify the paper loaded in Tray 3 is supported media.

2. Reduce the amount of media in the tray and reposition the guides to fit firmly
against the media.
3. Inspect and/or clean the pick roller assembly.
4. Run the Tray 3 Pick Shaft test.
5. Ensure ground integrity of the printer, see page 4-77.
6. Push up on the nudger roller until it is captured by the actuator arm.
7. Run the Pick Clutch test, replace the pick clutch.
8. Run the Media Path Drive test.
9. Replace the pick roller assembly.
10.Replace the Tray 3 525-sheet feeder.

Y2D Tray 4 media size sensor unexpectedly activated during warm-up.

Y2E Tray 4 media size sensor unexpectedly activated during printer ready.

Y2F Tray 4 media size sensor unexpectedly activated while printer in fault state.

Y2L Tray 4 media size sensor unexpectedly activated while printer in standby.

Y2M Tray 4 media size sensor unexpectedly activated while picking from Tray 2.

Y2N Tray 4 media size sensor unexpectedly activated while picking from Tray 3.

Y2P Tray 4 media size sensor unexpectedly activated while picking from Tray 4.

Y2Q Tray 4 media size sensor unexpectedly activated while picking from Tray 1.

Y2R Tray 4 media size sensor unexpectedly activated while duplexing.

Y2S Tray 4 media size sensor unexpectedly activated while paper staged for print.

Y2T Tray 4 media size sensor unexpectedly activated while transfixing the print.

Y2V Tray 4 media size sensor unexpectedly activated while the printer drum
maintenance cycle was being performed.

Y2W Tray 4 media size sensor unexpectedly activated while printer imaging.

Y2X Tray 4 media size sensor unexpectedly activated while exiting print.

1. Ensure ground integrity of the printer, see page 4-77.

2. Ensure the paper guides are correctly set.
3. Run the Monitor Sensors test to test the media size sensor.
4. Replace the Tray 4 525-Sheet Feeder.
5. Replace the pivot arm.

Z2A Tray 4 pick flag triggered unexpectedly during abnormal shutdown.

Z2B Tray 4 pick flag triggered unexpectedly during normal shutdown.

Service Manual 3-71

Jam Code Troubleshooting Procedures (Continued)
Z2C Tray 4 Pick flag triggered unexpectedly during mechanical recovery.

Z2D Tray 4 pick flag triggered unexpectedly during warm-up.

Z2E Tray 4 pick flag triggered unexpectedly while printer ready.

Z2F Tray 4 pick flag triggered unexpectedly while printer in fault state.

Z2L Tray 4 pick flag triggered unexpectedly while printer in standby.

Z2M Tray 4 pick flag triggered unexpectedly while pick from Tray 2.

Z2N Tray 4 pick flag triggered unexpectedly while pick from Tray 4.

Z2P Tray 4 pick flag triggered unexpectedly while pick from Tray 4.

Z2Q Tray 4 pick flag triggered unexpectedly while pick from Tray 1.

Z2R Tray 4 pick flag triggered unexpectedly while duplexing.

Z2S Tray 4 pick flag triggered unexpectedly while paper staged for print.

Z2T Tray 4 pick flag triggered unexpectedly while transfixing the print.

Z2V Tray 4 pick flag triggered unexpectedly while the printer drum maintenance cycle
was being performed.

Z2W Tray 4 pick flag triggered unexpectedly during printer imaging.

Z2Z Tray 4 pick flag triggered unexpectedly while exiting print.

1. Ensure ground integrity of the printer, see page 4-77.

2. Run the Monitor Sensors test to test the media size sensor.
3. Replace the 525-Sheet Feeder.
4. Replace the pivot arm.

Z3B Tray 4 pick flag sensor timed out during normal shutdown.

Z3D Tray 4 pick flag sensor timed out during warm-up.

Z3E Tray 4 pick flag sensor timed out during wile printer ready.

Z3F Tray 4 pick flag sensor timed out while printer in fault state.

Z3L Tray 4 pick flag sensor timed out while printer in standby.

Z3M Tray 4 pick flag sensor timed out while pick from Tray 2.

Z3N Tray 4 pick flag sensor timed out while pick from Tray 4.

Z3P Tray 4 pick flag sensor timed out while pick from Tray 4.

Z3Q Tray 4 pick flag sensor timed out while pick from Tray 1.

Z3R Tray 4 pick flag sensor timed out while duplexing.

3-72 Phaser 8400/8500/8550 Color Printer

Jam Code Troubleshooting Procedures (Continued)
Z3V Tray 4 pick flag sensor timed out while the printer drum maintenance cycle was
being performed.

Z3W Tray 4 pick flag sensor timed out while printer imaging.

Z3S Tray 4 pick flag sensor timed out while paper staged for print.

Z3T Tray 4 pick flag sensor timed out while transfixing the print.

Z3Z Tray 4 pick flag sensor timed out while exiting print.

1. Verify the paper loaded in Tray 4 is the correct size and type.
2. Inspect/clean the pick roller assembly. Replace if necessary.
3. Run the Tray 4 Pick Shaft test
4. Replace the Tray 4 525-Sheet Feeder.

Service Manual 3-73

General
Troubleshooting
In this chapter...
■ Service Diagnostics
■ Service Diagnostics Mode Menu
■ Check Menu Definition Tables
■ Electronics Troubleshooting
■ Ensuring Ground Integrity
■ Paper Path and Media-Based Problems
■ Operating System and Application Problems

Section
4
Introduction
This chapter covers the general start-up, Power On Self Test (POST), and power
supply operations of the printer to aid in troubleshooting problems not associated with
a Control Panel error message or error code. For troubleshooting problems associated
with an error code or Control Panel error message, notes on how to use the
troubleshooting procedure tables, and how to use service diagnostics, see Chapter 3
"Error Messages and Codes" on page 3-1. The Printer Status page also contains useful
troubleshooting information. This page provides general printer information, life
information for all consumables, printhead cleaning and power cycles, and jam and
error code information.
Troubleshooting procedures will isolate a problem to a specific component or
subassembly, in some cases including the wiring harness. If you go through the
procedures in a troubleshooting table and still are unable to solve the problem, re-read
the Theory of Operations for the problem area and ensure that you understand how
that section of the printer is supposed to function.

Hidden Service Menu

The Hidden Service Menu provides access to a large group of information pages and
functions usable for diagnosing and correcting printer malfunctions and accessing
special features. Display the Hidden Service Menu as follows:
1. On the Control Panel, press the Down Arrow button to select Troubleshooting
and then press OK.
2. Press the Down Arrow button to select Service Tools, and then press OK.
3. While pressing and holding down the Up Arrow button, press the Down Arrow
button to display the Hidden Service Menu.

Menu Item Description

Test Prints See "Analyzing Service Test Prints" on page 5-33 for a
complete explanation of each test print available.

Startup Page Prints a page with basic printer configuration and

networking information.

Eliminate Light Stripes Performs a cleaning procedure to remove light stripes in

prints; this process will take about 5 minutes.

Fault History Displays available information regarding the last 15 faults

reported by a test and/or the print engine.

Jam History Displays available information regarding the last 20 Jams

reported by a test and/or the print engine.

Diagnostic History (8500) Displays each diagnostic test performed on the printer.

4-2 Phaser 8400/8500/8550 Color Printer

Menu Item Description

Diagnostic History (8500/8550) Displays a list of all recent diagnostic tests.

Enter Diagnostic Mode See "Service Diagnostics Mode Menu" on page 4-5 for a
complete explanation of each diagnostic routine.

Reset NVRAM Provides access to reset the printer back to its factory-
default settings and erase all network settings. If
possible, print the Configuration Page before resetting
NVRAM.

Power Saver Timeout Selects the Power Saver Timeout, the amount of time the
printer must be idle before changing to Power Saver low-
energy consumption mode, per ENERGY STAR\256
guidelines.
Reset Printer Resets all items in the Printer Controls menu to their
default values.

Head Adjust This is for manufacturing or engineering use only.

Adjust X-axis scale This is for manufacturing or engineering use only.

Drift Compensation This is for manufacturing or engineering use only.

Head-to-Drum Adjust This is for manufacturing or engineering use only.

Wiper adjust (8500) Adjusts the tension on the wiper blade (for engineering
use only).

Purge adjust (8500) When replacing a purge pump different than the
manufactured pump, you may need to adjust the amount
of pressure in the pump using this menu item.

Reset Ink Loader (8500) Resets the ink loader ink stick count.
Service Usage Profile Prints pages with detailed printer-usage information.

Print OCR Usage Profile Prints using a font optimized for FAX.

Engine Copy Count Displays engine copy count.

Head Serial Number Displays the printhead serial number.

Head Cal Date Displays the date the printhead was calibrated.

Head Version Displays the printhead version.

Engine Firmware Version Displays the engine firmware version.

2-Sided Printing Oil Chase Enables a chase page to follow a 2-sided printing job.

Envelope Oil Chase Enables a chase page to follow an envelope print job.
Center Image (8400) Centers the image by adjusting the margin (not
operational).

Exit Exits the Hidden Service Diagnostics Menu and returns

to the previous menu.

General Troubleshooting 4-3

Service Diagnostics
The printer has built-in diagnostics to aid in troubleshooting problems with the
printer. The Service Diagnostics Menu provides a means to test sensors, motors,
switches, clutches, fans and solenoids. Diagnostics also contain functions to report
printer status and some NVRAM access.
Service diagnostics are to be executed through the Control Panel by a certified service
technician only. Service Diagnostics can be entered one of two ways:

Entering Service Diagnostics without Rebooting the Printer:

This method of entering diagnostics is to allow customers to be diverted to service
diagnostics in order to perform some tests.
1. Display the Hidden Service Menu as described in "Hidden Service Menu" on
page 4-2.
2. Scroll down to Enter Diagnostics and press the OK button.

Entering Service Diagnostics by Rebooting the Printer (8400):

1. Turn the printer power OFF.
2. Press and hold the Back and Help buttons.
3. Turn the printer power ON while continuing to hold the Back and Help buttons
for approximately 30 seconds until the Control Panel indicates Diagnostic
Menu.

Entering Service Diagnostics by Rebooting the Printer (8500/8550):

1. Turn the printer power ON.
2. Wait for the Xerox logo to begin moving across the display.
3. Before the logo is centered on the display (stops moving), press and hold the
Back and Help buttons on the Control Panel.
4. Hold both buttons until the display reads Beginning Service Mode
Initialization. Release the buttons and the printer reboots into service mode
with the Service Diagnostics menu displayed.

4-4 Phaser 8400/8500/8550 Color Printer

Service Diagnostic Control Panel Button Descriptions

Button Function

BACK Returns to the prior higher level menu structure, if available. Cancels the display
of test results on the Control Panel.
If help text is displayed on the Control Panel, pressing BACK will restore the
current menu item and remove the help text.

CANCEL Cancels certain functions of the printer.

HELP Provides help information, if available.
Press any key to advance through the help text.

UP Scrolls up one menu item within a menu list. This control does not ‘wrap’.
Used to increment data in tests requiring user input.

DOWN Scrolls down one menu item within test results.

This control does not ‘wrap’.
OK Enters the highlighted menu. Executes the current test item.

NOTE: Pressing any key may cause an abort if allowed by the test being performed. A power
cycle is used to arbitrarily stop a test.

Service Diagnostics Mode Menu

This mode can be entered from the Hidden Service Menu. All diagnostics are
available in this mode.
The printer reboots after entering or exiting all diagnostic modes. The printer will
keep the printer thermals hot during diagnostics to avoid unnecessary cleaning cycles.
If a diagnostic test runs into a problem while initializing the heaters a message will
display, “Test Fault, can’t warm up - press any button”, you can still continue to run
diagnostics under this condition.

Note
If the heaters are ON while entering diagnostics, they will remain ON while
diagnostics are being run. If the heaters are OFF while entering diagnostics,
they will remain OFF. Utilize the Exercise Heaters function if it is necessary
to turn ON/OFF the heaters.

General Troubleshooting 4-5

Service Diagnostics Menu Map
Menu Map

Menu Description

Main Menu Displays general help text describing the general operation of the
Control Panel/menu system.

Development Menu A temporary submenu containing some development functions

and access to tests still under development.

Return to Customer Exits service diagnostics and runs through POST to Ready.
Mode

Check Menu Check All See the individual table descriptions

Activators Menu starting on page 4-12 for all Check/
Shafts Menu Activator menu items.
Fans Menu
Heaters Menu
Paper Path Menu
Drive Menu
Drum Menu (8500)
Motors Menu
Misc. Menu

Monitor Menu
A submenu containing a set of functions for passively viewing or monitoring printer
mechanical measurements.

Sensors Monitors all mechanically activated

digital sensors except for the Control
Panel buttons. Whenever a state
change is detected it is reported on the
Control Panel.

Encoders Monitors each of the non-temperature

analog sensors (Tray 1 width, Y, Media
Path, and Process motor encoders).

Temps Monitors each of the thermal sensors.

Shows the current thermal control loop
setpoint (first value) and the current
sensor temperature (second value).

Heaters Monitors each of the heaters. Shows if

the heater is currently enabled (first
value) and what percentage of
maximum power is currently allocated
(second value).

Line Voltage Monitors line voltage as seen by the

power supply. Reports max and min
values.

4-6 Phaser 8400/8500/8550 Color Printer

Menu Map (Continued)

Menu Description

Control Panel Monitors Control Panel buttons and

Buttons reports button presses.

Exercise Menu
A submenu containing a set of functions for actively causing mechanical actions which
may then be observed.

Activators Menu Pulses the specified activator to cause

it to generate some sound or motion.

Exercise All Cycles each of the listed activators 4

times in sequence until interrupted by a
Control Panel button press.

Tray 1 Pick Cycles the activator repeatedly until

Solenoid interrupted by a Control Panel button
press.

Tray 2 Pick Cycles the activator repeatedly until

Clutch interrupted by a Control Panel button
press.

Tray 3 Pick Cycles the activator repeatedly until

Clutch interrupted by a Control Panel button
press. If not installed generates an
“Option not detected” message.

Tray 4 Pick Cycles the activator repeatedly until

Clutch interrupted by a Control Panel button
press. If not installed generates an
“Option not detected” message.

Deskew Clutch Cycles the activator repeatedly until

interrupted by a Control Panel button
press.

Pre-heater Cycles the preheater solenoid until

Solenoid (8500/ interrupted by pressing the Control
8550) Panel button.

Strip Solenoid Cycles the activator repeatedly until

interrupted by pressing the Control
Panel button.

Tilt Solenoid Cycles the tilt solenoid until interrupted

(8500/8550) by pressing the Control Panel button.

Head Cycles the activator repeatedly until

Maintenance interrupted by a Control Panel button
Clutch press.

General Troubleshooting 4-7

Menu Map (Continued)

Menu Description

Purge Vent Cycles the activator repeatedly until

Solenoid interrupted by a Control Panel button
press.

110V/220V Drum Cycles the activator repeatedly until

Heater Relay(s) interrupted by a Control Panel button
press.

Exercise Motors/ These functions drive the specified

Shafts Menu motor or shaft sufficiently to generate
easily observed motion without making
substantial change to the state of the
printer.

Exercise All Cycles each of the listed motors/shafts

3 times in sequence until interrupted by
a Control Panel button press.

Process Motor Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press.

Y-axis Motor Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press.

X-axis Motor Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press.

Purge Pump Cycles the motor/shaft repeatedly until

Motor interrupted by a Control Panel button
press.

Drum Fan Motor Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press.

Media Path Cycles the motor/shaft repeatedly until

Motor Fan Motor interrupted by a Control Panel button
press.

Media Path Cycles the motor/shaft repeatedly until

Motor & Shafts interrupted by a Control Panel button
press.

Transfix Cam Cycles the motor/shaft repeatedly until

Shaft interrupted by a Control Panel button
press.

Drum Cycles the motor/shaft repeatedly until

Maintenance interrupted by a Control Panel button
Cam Shaft press.

4-8 Phaser 8400/8500/8550 Color Printer

Menu Map (Continued)

Menu Description

Deskew Shaft Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press.

Wiper Shaft Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press.

Tray 1 Pick Shaft Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press.

Tray 2 Pick Shaft Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press.

Tray 2 Lift Motor Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press. If not installed generates an
“Option not detected” message.

Tray 3 Pick Shaft Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press.

Tray 4 Pick Shaft Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press. If not installed generates an
“Option not detected” message.

Tray 3 Lift Motor Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press. If not installed generates an
“Option not detected” message.

Tray 3 Motor & Cycles the motor/shaft repeatedly until

Shafts interrupted by a Control Panel button
press. If not installed generates an
“Option not detected” message.

Tray 4 Pick Shaft Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press. If not installed generates an
“Option not detected” message.

Tray 4 Lift Motor Cycles the motor/shaft repeatedly until

interrupted by a Control Panel button
press. If not installed generates an
“Option not detected” message.

General Troubleshooting 4-9

Menu Map (Continued)

Menu Description

Tray 4 Motor & Cycles the motor/shaft repeatedly until

Shafts interrupted by a Control Panel button
press. If not installed generates an
“Option not detected” message.

Exercise Heaters Allows the heaters to forced to an ON

Menu or OFF condition or to be toggled from
one condition to the other. Also,
provide monitoring to observe the
resulting heater power or temperature.

Monitor heaters Monitors heater power.

Monitor Monitors heater temperature.

Temperatures

All Heaters On Turns all heaters On.

All Heaters Off Turns all heaters Off

Toggle Printhead Toggles printhead heaters to opposite

Heaters state.

Toggle Preheat Toggles preheat heater to opposite

Heater state.

Toggle Drum Toggles drum heater to opposite state.

Heater

Toggle Ink Melt Toggles ink melt heaters to opposite

Heaters state. There is a melt heater for each of
the four colors.

Control Panel Exercises the Control Panel LCD/LED

Display outputs.

Cycle LED Cycles the LED through a red/Yellow/

Green sequence.

Set display dark Sets the LCD display dark.

Test backlight Changes the display backlight from off

to max.

Set display light Sets the LCD display light.

Function Menu A submenu containing a set of

functions for commanding more
complex actions by portions of the
printer mechanism.

Initialize Mechanism Performs a simplified version of the

power up mechanical initialization
sequence.

4-10 Phaser 8400/8500/8550 Color Printer

Menu Map (Continued)

Menu Description

Print DMU Blot Raises the DM unit up against the

drum, then does a Chase sequence.
The result is an oil print of the contact
of the DM unit with the drum (about 2/3
of the way down the page).

Display Fault History A function that displays the current

contents of the Fault History NVRAM
store.

Access PE NVRAM A restricted function that provides read/

Parameters write access to selected PE NVRAM
parameters.

Clear Fault History A restricted function that clears the

Fault History NVRAM store.

Clear ISC Fault Resets the Ink Stick Count (ISC) fault
condition. To avoid a reoccurrence,
check the ink shapes and the ink stick
flags.

Clear PS NVRAM A restricted function that clears the PS

NVRAM to be rebuilt with defaults at
the next power up.

Clear PE NVRAM A restricted function that clears the PE

NVRAM to be rebuilt with defaults at
the next power up.

Set PE NVRAM to A restricted function that sets the PE

Defaults NVRAM parameters to the default
values.

General Troubleshooting 4-11

Check Menu Definition Tables
A submenu containing a set of extensive tests that return measured mechanism
parameters for comparison against stated limits.
Refer to the table associated with each test for their normal operating ranges. In cases
where insufficient baseline data is available, the results have been left blank. All
results from tests that move paper through the printer were collected using 24 lb. bond
paper.

Note
Collecting 2 or 3 samples of the test data is recommended before deciding on
a course of action. Many of the tests rely on mechanical positions and slight
changes can effect the results. Ensure that the printer is not out of paper, ink or
maintenance kit life. The diagnostics routines are not designed to address all of
these conditions consistently.
If a test result differs significantly from the typical values defined in the
following tables, check the entire system containing the problem component to
ensure a problem within the system is not influencing the test results.

To access the Check Menus enter Service Diagnostics and go to Check Menu -->
Check Activators Menu.
The Check All selection will run all check tests, taking 1.5 hours to complete and is
not for use by field technicians.

4-12 Phaser 8400/8500/8550 Color Printer

Check / Activators Menu
Head Maintenance Clutch
Gathers data on the performance of the head maintenance clutch coil.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Peak Power (watts) 3.0 to 5.9 3.2 to 6.3 Reports the profile max power
value.

1 Average Power 2.8 2.2 to 3.5 Reports the average power

(watts) during the constant portion of the
profile.

Deskew Clutch
Gathers data on the performance of the deskew clutch coil.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Peak Power (watts) 2.5 to 5.3 3.0 to 5.8 Reports the profile max power.

1 Average Power 2.2 to 5.3 1.5 to 3.0 Reports the average power
(watts) during the constant portion of the
profile.

Tray 1 Pick Solenoid

Gathers data on the performance of the Tray 1 pick solenoid coil and flapper.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Peak Power (watts) 20.0 to 30 20 to 25 Reports the profile max power

value.

1 Average Power 20.0 to 30 19 to 26 Reports the average power

(watts) during the constant portion of
the profile.

2 Min Power (watts) -5.0 to -0.4 Reports the min power

following power off.

General Troubleshooting 4-13

Tray 1 Pick Solenoid
Gathers data on the performance of the Tray 1 pick solenoid coil and flapper.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

3 Peak Power Time 0.05 to 0.19 Reports time after solenoid

(sec) power on that the peak power
occurred.

4 Initial Average 17 to 26 Reports the average power

Power (watts) following power on.

Tray 2, Tray 3, Tray 4, Pick Clutch

Gathers data on the performance of the pick clutch coil for Trays 2 through 4. The same type of
clutch is used for each tray.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Peak Power (watts) 2.5 to 5.5 3.0 to 6.0 Reports the profile max power
value.

1 Average Power 2.5 to 5.5 2.0 to 6.5 Reports the average power
(watts) during the constant portion of
the profile.

Strip Solenoid
Gathers data on the performance of the stripper solenoid coil and plunger.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Peak Power (watts) 8.0 to 15 22 to 27 Reports the profile max power

value.

1 Average Power 8.0 to 15 20.0 to 30.0 Reports the average power

(watts) during the constant portion of
the profile.

4-14 Phaser 8400/8500/8550 Color Printer

Purge Vent Solenoid
Gathers data on the performance of the purge vent solenoid coil.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Peak Power (watts) 0.5 to 1.2 -.12 to Reports the profile max power
1.2 value.

1 Average Power 0.4 to 1.2 .15 to 1.2 Reports the average power
(watts) during the constant portion of the
profile.

Drum Heater Relay

Gathers data on the performance of the drum heater dual relay assembly by energizing each
relay for a short time and capturing the resulting power draw.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 220 V Coil Peak .2 to 1.2 Reports the profile max power

Power (watts) value.

1 220 V Coil Average .2 to 1.2 Reports the average power

Power (watts) during the constant portion of the
profile.

2 220 V Coil Min .2 to .45 Reports the min power following

Power (watts) power off.

3 220 V Coil Peak Reports time after solenoid

Power Time (sec) power on that the peak power
occurred.

4 220 V Coil Initial .2 to .45 Reports the average power

Average Power following power on.
(watts)

5 110 V Coil Peak .2 to 1.0 Reports the profile max power

Power (watts) value.

6 110 V Coil Average .2 to 1.0 Reports the average power

Power (watts) during the constant portion of the
profile.

7 110 V Coil Min .2 to .45 Reports the min power following

Power (watts) power off.

General Troubleshooting 4-15

Drum Heater Relay
Gathers data on the performance of the drum heater dual relay assembly by energizing each
relay for a short time and capturing the resulting power draw.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

8 110 V Coil Peak Reports time after solenoid

Power Time (sec) power on that the peak power
occurred.

9 110 V Coil Initial Reports the average power

Average Power following power on.
(watts)

4-16 Phaser 8400/8500/8550 Color Printer

Check Shafts Menu
Deskew Shaft
Runs the media path drive train and engages the deskew clutch on the fly then disengages the
clutch. The test is repeated in both directions to determine clutch characteristics, steady state
drive requirements, bearing status, etc.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Time to CCW On 0.01 to .01 to.04 Reports how long it takes the MP
peak fe (sec). 0.04 motor servo system to react to
the sudden addition of the
deskew shaft load.
Larger values may show a
slipping/slow to engage clutch.

1 CCW On peak fe. 540 to 2.0 to 8.0 Reports peak effort needed to
750 accelerate the deskew shaft
load. A smaller value could
indicate a slipping clutch.

2 CCW On fe settling 0.017 to 0 to .2 Reports the time it takes the MP

time (sec). 0.21 motor servo system to "settle
down" after the sudden addition
of the deskew shaft load.
A longer time could indicate a
looseness in the deskew shaft
assembly or a slipping clutch.

3 CCW On average fe. 250 to 1.0 to 2.5 Reports the average effort
600 required to rotate the deskew
shaft in the CCW direction at a
constant velocity.
An unusual value could indicate
a difference in the composition
and/or number of the rollers, the
nip pressure, or out of range
mechanical dimensions due to
wear or contamination (such as
paper dust increasing the
effective diameter of a roller).

4 CCW On fe ripple. 115 to 0 to 2.0 Reports the variation of effort

360 required to rotate the deskew
shaft in the CCW direction at a
constant velocity.
A larger value could indicate
particles in the gears or non
uniform contamination of a roller
(causing a lump).

General Troubleshooting 4-17

Deskew Shaft (Continued)
Runs the media path drive train and engages the deskew clutch on the fly then disengages the
clutch. The test is repeated in both directions to determine clutch characteristics, steady state
drive requirements, bearing status, etc.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

5 CCW Off fe settling 0.010 to 0 to .5 Reports the time it takes the MP

time (sec). 0.20 motor servo system to "settle
down" after the sudden release
of the deskew shaft load.
A larger value can indicate a
slow to release or dragging
clutch.

6 Time to CW On 0.010 to 0 to .05 Reports a time that indicates

peak fe (sec). 0.06 how long it takes the MP motor
servo system to react to the
sudden addition of the deskew
shaft load. Larger values may
indicate a slipping or slow to
engage clutch.

7 CW On peak fe. -950 to -7.0 to Reports the peak effort required

-450 -2.0 to accelerate the deskew shaft
load. A smaller value could
indicate a slipping clutch.

8 CW On fe settling 0.010 to 0 to .2 Reports the time it takes the MP

time (sec). 0.20 motor servo system to "settle
down" after the sudden addition
of the deskew shaft load.
A longer time could indicate a
looseness in the deskew shaft
assembly or a slipping clutch.

9 CW On average fe. -610 to -3 to 1.3 Reports the average effort

-220 required to rotate the deskew
shaft in the CW direction at a
constant velocity.
An unusual value could indicate
a difference in the composition
and/or number of the rollers, the
nip pressure, or out of range
mechanical dimensions due to
wear or contamination (such as
paper dust increasing the
effective diameter of a roller).

4-18 Phaser 8400/8500/8550 Color Printer

Deskew Shaft (Continued)
Runs the media path drive train and engages the deskew clutch on the fly then disengages the
clutch. The test is repeated in both directions to determine clutch characteristics, steady state
drive requirements, bearing status, etc.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

10 CW On fe ripple. 110 to -2.25 to Reports the variation of effort

400 -1.0 required to rotate the deskew
shaft in the CW direction at a
constant velocity.
A larger value could indicate
particles in the gears or non
uniform contamination of a roller
(causing a lump).

11 CW Off fe settling 0.010 to .01 to .05 Reports the time it takes the MP
time (sec). 0.20 motor servo system to "settle
down" after the sudden release
of the deskew shaft load.
A larger value could indicate a
dragging or slow to release
clutch.

General Troubleshooting 4-19

Check Paper Path Menu
Wiper Shaft
Runs the media path drive train and engages the head maintenance clutch on the fly then
disengages the clutch. The test is repeated in both directions to determine clutch characteristics,
steady state drive requirements, bearing status, etc.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Time to CCW On 0.009 to .02 to 1.0 Reports how long it takes the MP
peak fe (sec). 0.16 motor servo system to react to
the sudden addition of the wiper
shaft load. Larger values may
indicate a slipping or slow to
engage clutch.

1 CCW On peak fe. 25 to 100 .015 to Reports the peak effort required
1.4 to accelerate the wiper shaft
load. A smaller value could
indicate a slipping clutch.

2 CCW On fe settling -2.1 to -.03 to .3 Reports the time it takes the MP

time (sec). 0.25 motor servo system to "settle
down" following the sudden
addition of the wiper shaft load.
A longer time could indicate a
looseness in the wiper shaft
assembly or a slipping clutch.

3 CCW On average fe. 10 to 50 -.1 to 0 Reports the average effort

required to rotate the wiper shaft
in the CCW direction at a
constant velocity.
An unusual value could indicate
a difference in the composition
and/or number of the rollers, the
nip pressure, or out of range
mechanical dimensions due to
wear or contamination (such as
paper dust increasing the
effective diameter of a roller).

4 CCW On fe ripple. 25 to 100 .08 to .31 Reports the variation of effort

needed to rotate the wiper shaft
in the CCW direction at a
constant velocity. A larger value
could indicate particles in the
gears or non uniform
contamination of a roller
(causing a lump).

4-20 Phaser 8400/8500/8550 Color Printer

Wiper Shaft (Continued)
Runs the media path drive train and engages the head maintenance clutch on the fly then
disengages the clutch. The test is repeated in both directions to determine clutch characteristics,
steady state drive requirements, bearing status, etc.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

5 CCW Off fe setting 0.004 to .015 to Reports the time it takes the MP
time (sec). 0.15 .20 motor servo system to “settle
down” after the sudden release
of the wiper shaft load. A larger
value may show a dragging or
slow to release clutch.

6 Time to CW On 0.005 to .02 to Reports how long it takes the MP

peak fe (sec). 0.20 .045 motor servo system to react to
the sudden addition of the wiper
shaft load.
Larger values may indicate a
slipping or slow to engage
clutch.

7 CW On peak fe. -275 to -.15 to Reports the peak effort required

-10 0.4 to accelerate the wiper shaft
load.
A smaller value could indicate a
slipping clutch.

8 CW On fe settling -10 to 1 -.04 to Reports the time it takes the MP

time (sec). .23 motor servo system to "settle
down" following the sudden
addition of the wiper shaft load.
A longer time could indicate a
looseness in the wiper shaft
assembly or a slipping clutch.

9 CW On average fe. -50 to 15 .02 to .2 Reports the average effort

required to rotate the wiper shaft
in the CW direction at a constant
velocity.
An unusual value could indicate
a difference in the composition
and/or number of the rollers, the
nip pressure, or out of range
mechanical dimensions due to
wear or contamination (such as
paper dust increasing the
effective diameter of a roller).

General Troubleshooting 4-21

Wiper Shaft (Continued)
Runs the media path drive train and engages the head maintenance clutch on the fly then
disengages the clutch. The test is repeated in both directions to determine clutch characteristics,
steady state drive requirements, bearing status, etc.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

10 CW On fe ripple. 20 to 75 0 to .4 Reports the variation of effort

needed to rotate the wiper shaft
in the CW direction at a constant
velocity.
A larger value may show
particles in the gears or non
uniform contamination of a roller
(causing a lump).

11 CW Off fe settling -5 to .01 .02 to .22 Reports the time it takes the MP
time (sec). motor servo system to "settle
down" after the sudden release
of the wiper shaft load.
A larger value could indicate a
dragging or slow to release
clutch.

Tray 1 Pick Shaft

Runs the media path drive train and engages the tray 1 pick solenoid on the fly. The pick shaft
goes through two full revolutions while drive requirements are determined.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Off average MP fe. 800 to Reports the average MP fe

(mpts). 1500 during the run in interval before
the pick shaft is engaged.

1 On response time. -1.5 to Reports the time between pick

(sec). 0.95 solenoid activation and a
detectable response from the
MP drive system indicating that
pick shaft engagement. A higher
value of R1 could indicate that
the missing tooth gear engaged
more slowly than usual, which
could be a problem with the lift
plate spring tension, the
condition of the sliding surfaces
between the cams and the
followers, drag on the pick shaft,
or problems with the drive gears
(missing teeth, etc.).

4-22 Phaser 8400/8500/8550 Color Printer

Tray 1 Pick Shaft (Continued)
Runs the media path drive train and engages the tray 1 pick solenoid on the fly. The pick shaft
goes through two full revolutions while drive requirements are determined.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

2 Initial average MP fe. -1 to Reports the average MP fe

(mpts). 1400 immediately following the pick
shaft engagement.
A higher value of R2 could
indicate extra friction between
the cams and the lift plate
followers (wear, contamination,
etc.), as well as high lift plate
spring tension or higher shaft
bearing drag. Also, if the missing
tooth gear did not kick forward
and engage, this value would be
unchanged from R0.

3 Transition MP fe min. 750 to Reports the minimum MP fe

(mpts). 1800 value at the transition point
between breaking separator pad
contact and the continued
depression of the lift plate.
Value reflects the effort needed
to rotate the pick shaft and
compress the lift spring. A higher
value of R3 could show higher
cam/bearing friction and/or lift
plate spring strength.

4 Contact average fe. 120 to Reports the average MP fe while

2000 the pick roller is contacting the
separator pad. This value should
reflect the coefficient of friction
between the separator pad and
the pick roller. This value may be
effected by contamination or
glazing.

5 Pushdown MP fe 750 to Reports the peak MP fe during

max. 2000 the interval when the pick cams
are depressing the lift plate.
A higher value here could
indicate issues with the cam
surfaces or the spring
compression force.

6 Final average MP fe. 900 to Reports the average MP fe

(mpts). 1500 following the re latching of the
missing tooth gear.
This value should be the same
as R0 if the missing tooth gear
successfully relatched.

General Troubleshooting 4-23

Tray 2, Tray 3, and Tray 4 Pick Shaft
Test is the same for each pick shaft although for tray 2 the media path motor is used and for the
525-sheet feeders the corresponding pick/transport motor is used. Test determines if the shaft
can be driven by the clutch, if the nudger rollers are being driven, and the pick pad/nudger roller
friction.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Time to On peak fe Reports how long it takes the MP

(sec). motor servo system to react to
the sudden addition of the Tray 2
pick shaft load. Larger values
may indicate a slipping or slow to
engage clutch.

1 On peak fe. Reports the peak effort required

to accelerate the Tray 2 pick
shaft load. A smaller value could
indicate a slipping clutch.

2 On fe settling time Reports the time it takes the MP

(sec). motor servo system to "settle
down" after the sudden addition
of the Tray 2 pick shaft load.
A longer time could indicate
looseness in the Tray 2 pick shaft
assembly or a slipping clutch.

3 On average fe. Reports the average effort

needed to rotate the Tray 2 pick
shaft in the pick direction at a
constant velocity. An unusual
value could indicate a binding
shaft, missing pressure springs,
hard/dirty rollers, extra friction in
the pick truck assembly.

4 On fe ripple. Reports the variation of effort

required to rotate the Tray 2 pick
shaft in the pick direction at a
constant velocity. A larger value
could indicate particles in the
gears or non uniform
contamination of a roller (causing
a lump).

5 Off fe settling time Reports the time it takes the MP

(sec). motor servo system to "settle
down" after the sudden release
of the Tray 2 pick shaft load.
A larger value could indicate a
dragging or slow to release
clutch.

4-24 Phaser 8400/8500/8550 Color Printer

Tray 2, Tray 3, and Tray 4 Pick Shaft (Continued)
Test is the same for each pick shaft although for tray 2 the media path motor is used and for the
525-sheet feeders the corresponding pick/transport motor is used. Test determines if the shaft
can be driven by the clutch, if the nudger rollers are being driven, and the pick pad/nudger roller
friction.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

6 Time to lift plate up Reports the time between the

(sec). activation of the Tray 2 lift motor
and the detection of the raised lift
plate. Out of range values may
indicate a problem with the lifting
mechanism (which could effect
the following friction
measurement), or media left in
the tray.

7 Plate lifted average Reports the peak effort required

fe. to drive the pick shaft when the
nudger roller is in contact with
the separator pad.
A smaller value could indicate a
slipping clutch, missing nudger
assembly pressure spring, or
glazed/dirty roller/pad.

Paper Drive Power

Test picks paper from selected tray (test currently supports picking from Tray 2 only) and moves it
through either the simplex or duplex paper path to determine paper path power requirements.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Tray Reports the tray from which the

test paper was picked.

1 Paper Size Reports the size of the picked

paper.

2 Unused

3 Unused

4 Tray 2 Pick Average Reports average of the power

Power (watts) over the pick interval (begin pick
to Deskew sensor).

General Troubleshooting 4-25

Paper Lead Edge Times
Paper is picked and moved through either simplex or duplex paper path to determine leading
edge arrival time at each paper path sensor. R values have alternate definitions or are unused
depending on the pick tray and if simplex or duplex path was selected.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

Common

0 Tray Reports the tray from which the

test paper was picked

1 Paper Size Reports the size of the picked

paper.

Tray 4 Pick

2 Tray 4 Pick Interval Reports the interval from the time

(us) the engine software is
commanded to start the tray 4
pick process until the Tray 4 Pick
sensor activates.

3 Tray 4 Transport Reports the interval from the Tray

Interval (us) 4 Pick sensor activation until the
Tray 3 Pick sensor activates.

4 Tray 3 Transport Reports the interval from the Tray

Interval (us) 3 Pick sensor activation until the
Deskew sensor activates.

Tray 3 Pick

2 Unused

3 Tray 3 Pick Interval Reports the interval from the time

(us) the engine software is
commanded to start the tray 3
pick process until the Tray 3 Pick
sensor activates.

4 Tray 3 Transport Reports the interval from the Tray

Interval (us) 3 Pick sensor activation until the
Deskew sensor activates.

Tray 2 Pick

2 Unused

3 Unused

4-26 Phaser 8400/8500/8550 Color Printer

Paper Lead Edge Times (Continued)
Paper is picked and moved through either simplex or duplex paper path to determine leading
edge arrival time at each paper path sensor. R values have alternate definitions or are unused
depending on the pick tray and if simplex or duplex path was selected.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

4 Tray 2 Pick Interval Reports the interval from the time

(us) the engine software is
commanded to start the tray 2
pick process until the Deskew
sensor activates.

Tray 1 Pick

2 Unused

3 Unused

4 Tray 1 Interval (us) Reports the interval from the time

the engine software is
commanded to start the tray 1
pick process until the Deskew
sensor activates.

Common

5 Stage Interval (us) Reports the interval from the time

the engine software is
commanded to start the stage
process until the Preheat sensor
activates. (part way through the
stage paper motion).

6 Transfix Interval (us) Reports the interval from the time

the engine software is
commanded to start the transfix
process until the Strip sensor
activates. (part way through the
paper transfix motion).

7 Exit Interval (us) Reports the interval from the time

the engine software is
commanded to start the transfix
process until the Exit sensor
activates (part way through the
paper transfix motion).

Simplex Path

General Troubleshooting 4-27

Paper Lead Edge Times (Continued)
Paper is picked and moved through either simplex or duplex paper path to determine leading
edge arrival time at each paper path sensor. R values have alternate definitions or are unused
depending on the pick tray and if simplex or duplex path was selected.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

8 Exited Interval (us) Reports the interval from the time

the engine software is
commanded to start the exit
process until the Exit sensor
deactivates.

Paper Trail Edge Times

Paper is picked and moved through either the simplex or duplex paper path to determine the
paper trailing edge arrival time at each paper path sensor. R values have alternate definitions or
are unused depending on the pick tray and if simplex or duplex path was selected.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

Common

0 Tray Reports the tray from which the

test paper was picked.

1 Paper Size Reports the size of the picked

paper.

Tray 4 Pick

2 Tray 4 Pick Trailing Reports the interval from the time

Edge Interval (us) the engine software is
commanded to start the tray 4
pick process until the Tray 4 Pick
sensor deactivates.

Tray 3 Pick

3 Tray 3 Pick Trailing Reports the interval from the time

Edge Interval (us) the engine software is
commanded to start the tray 3
pick process until the Tray 3 Pick
sensor deactivates.

Tray 2 Pick

2 Unused

4-28 Phaser 8400/8500/8550 Color Printer

Paper Trail Edge Times (Continued)
Paper is picked and moved through either the simplex or duplex paper path to determine the
paper trailing edge arrival time at each paper path sensor. R values have alternate definitions or
are unused depending on the pick tray and if simplex or duplex path was selected.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

3 Unused

Tray 1 Pick

2 Unused

3 Unused

Common

4 Deskew Trailing Reports the interval from the time

Edge Interval (us) the engine software is
commanded to start the transfix
process until the Deskew sensor
deactivates. (part way through
the paper transfix motion).

5 Preheat Trailing Reports the interval from the time

Edge Interval (us) the engine software is
commanded to start the transfix
process until the Preheat sensor
deactivates. (part way through
the paper transfix motion).

6 Strip Trailing Edge Reports the interval from the time

Interval (us) the engine software is
commanded to start the exit
process until the Strip sensor
deactivates (part way through the
paper exit motion).

Simplex Path

7 Exit Trailing Edge Reports the interval from the time

Interval (us) the engine software is
commanded to start the duplex
pick process until the Exit sensor
deactivates.

General Troubleshooting 4-29

Paper Sensor Bounce Times
Paper is picked and moved through either the simplex paper path to determine the paper trailing
edge bounce interval at each paper path sensor. R values have alternate definitions or are
unused depending on the pick tray and if simplex or duplex path was selected.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

Common

0 Tray Reports the tray from which the

paper was picked.

1 Paper Size Reports size of the picked paper.

Tray 4 Pick

2 Tray 4 Pick Bounce Reports the interval during which

Interval (us) the Tray 4 Pick sensor bounces
following the passage of the
paper trailing edge.

Tray 3 Pick

3 Tray 3 Pick Bounce Reports the interval during which

Interval (us) the Tray 3 pick sensor bounces
following the passage of the
paper trailing edge.

Tray 2 Pick

2 unused

3 unused

Tray 1 Pick

2 unused

3 unused

Common

4 Deskew Bounce Reports the interval during which

Interval (us) the Deskew sensor bounces
following the passage of the
paper trailing edge.

4-30 Phaser 8400/8500/8550 Color Printer

Paper Sensor Bounce Times (Continued)
Paper is picked and moved through either the simplex paper path to determine the paper trailing
edge bounce interval at each paper path sensor. R values have alternate definitions or are
unused depending on the pick tray and if simplex or duplex path was selected.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

5 Preheat Bounce Reports the interval during which

Interval (us) the Preheat sensor bounces
following the passage of the
paper trailing edge.

6 Strip Bounce Reports the interval during which

Interval (us) the Strip sensor bounces
following the passage of the
paper trailing edge.

7 Exit Bounce Interval Reports the interval during which

(us) the exit sensor bounces following
the passage of the paper trailing
edge.

Duplex Paper Drive Power

Test picks paper from selected tray (test currently supports picking from Tray 2 only) and moves it
through either the simplex or duplex paper path to determine paper path power requirements.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Tray Reports the tray from which the

test paper was picked.

1 Paper Size Reports the size of the picked

paper.

2 Unused

3 Unused

4 Tray 2 Pick Average Reports average of the power

Power (watts) over the pick interval (begin pick
to Deskew sensor).

General Troubleshooting 4-31

Duplex Paper Lead Edge Times
Paper is picked and moved through either simplex or duplex paper path to determine leading
edge arrival time at each paper path sensor. R values have alternate definitions or are unused
depending on the pick tray and if simplex or duplex path was selected.

Typical
Typical Value
Value (8500/
R# Definition (8400) 8550) Actions

8 Duplex Turnaround Reports the interval from the time

Interval (us) the engine software is
commanded to start the duplex
exit process until the Strip sensor
deactivates.

9 Duplex Pick Interval Reports the interval from the time

(us) the engine software is
commanded to start the duplex
pick process until the Deskew
sensor activates

10 Duplex Stage Reports the interval from the time

Interval (us) the engine software is
commanded to start the stage
process until the Preheat sensor
activates (part way through the
stage paper motion).

11 Duplex Transfix Reports the interval from the time

Interval (us) the engine software is
commanded to start the transfix
process until the Strip sensor
activates (part way through the
paper transfix motion).

12 Duplex Exit Interval Reports the interval from the time

(us) the engine software is
commanded to start the transfix
process until the Exit sensor
activates (part way through the
paper transfix motion).

13 Duplex Exited Reports the interval from the time

Interval (us) the engine software is
commanded to start the exit
process until the Exit sensor
deactivates.

4-32 Phaser 8400/8500/8550 Color Printer

Duplex Paper Trail Edge Times
Paper is picked and moved through either the simplex or duplex paper path to determine the
paper trailing edge arrival time at each paper path sensor. R values have alternate definitions or
are unused depending on the pick tray and if simplex or duplex path was selected.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

7 Exit Trailing Edge Reports the interval from the time

Interval (us) the engine software is
commanded to start the duple
pick process until the Exit sensor
deactivates.

8 Duplex Deskew Reports the interval from the time

Trailing Edge the engine software is
Interval (us) commanded to start the transfix
process until the Deskew sensor
deactivates (part way through the
paper transfix motion).

9 Duplex Preheat Reports the interval from the time

Trailing Edge the engine software is
Interval (us) commanded to start the transfix
process until the Preheat sensor
deactivates. (part way through
the paper transfix motion).

10 Duplex Strip Trailing Reports the interval from the time

Edge Interval (us) the engine software is
commanded to start the exit
process until the Strip sensor
deactivates (part way through the
paper exit motion).

11 Duplex Exit Trailing Reports the interval from the time

Edge Interval (us) the engine software is
commanded to start the duplex
pick process until the Exit sensor
deactivates.

General Troubleshooting 4-33

Duplex Paper Sensor Bounce Times
Paper is picked and moved through either the duplex paper path to determine the paper trailing
edge bounce interval at each paper path sensor. R values have alternate definitions or are
unused depending on the pick tray and if simplex or duplex path was selected.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

7 Exit Bounce Interval Reports the interval during which

(us) the Exit sensor bounces following
the passage of the paper trailing
edge during duplex turnaround.

8 Duplex Deskew Reports the interval during which

Bounce Interval (us) the Deskew sensor bounces
following the passage of the
paper trailing edge.

9 Duplex Preheat Reports the interval during which

Bounce Interval (us) the Preheat sensor bounces
following the passage of the
paper trailing edge.

10 Duplex Strip Bounce Reports the interval during which

Interval (us) the Strip sensor bounces
following the passage of the
paper trailing

11 Duplex Exit Bounce Reports the interval during which

Interval (us) the Exit sensor bounces following
the passage of the paper trailing
edge.

4-34 Phaser 8400/8500/8550 Color Printer

Check Drive Menu

Wiper Drive
This test moves the wiper drive mechanism through the complete range of its motion in each
direction and does an “on the fly” reversal to verify operability.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Up Motion Drive 120 to -.06 to -.4 Reports the average following

Error (uin) 275 error while move the wiper up
from the low limit to the lock
encounter point.

1 Up Motion Drive 35 to 150 .06 to .2 Reports the difference between

Error Ripple (uin) the max and min following error
over the same interval.

2 Up Distance (uin) 3200 to 4000 to Reports the difference between

4600 4350 the max and min limits of travel
when moving up.

3 Lock Encounter 1300 to 3500 to Reports the distance up from the

Distance (uin) 2500 4450 lower limit of travel at which the
head lock latch is encountered.

4 Lock Engage 350 to 2500 to Reports the distance up from the

Distance (uin) 700 4500 lower limit of travel at which the
head lock latch engages.

5 Lock Engage Peak -250 to .25 to 1.0 Reports the peak following error
(uin) -125 at the point the latch engages.

6 Down Motion Drive -250 to .25 to 1.0 Reports the average following
Error (uin) -125 error while move the wiper up
from the low limit to the lock
encounter point.

7 Down Motion Drive 40 to 150 .05 to .8 Reports the difference between

Error Ripple (uin) the max and min following error
over the same interval.

8 Down Distance (uin) 3200 to 4000 to Reports the difference between

4600 4350 the max and min limits of travel
when moving up.

9 Lock Disengage -2000 to -95 to -60 Reports the distance up from the
Distance (uin) -50 upper stall point at which the
head lock latch releases.

10 Lock Disengage -800 to .30 to 1.2 Reports the peak following error
Peak (uin) -150 at the point the latch releases

General Troubleshooting 4-35

Wiper Drive (Continued)
This test moves the wiper drive mechanism through the complete range of its motion in each
direction and does an “on the fly” reversal to verify operability.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

11 Bottom Encounter -2500 to -4250 to - Reports the distance up from the

Distance (uin) -1800 3900 upper limit of travel at which the
wiper first encounters the lower
travel limit.

12 Turnaround 0.001 to -0.05 to Reports the time following the

Recovery time (sec) 0.250 .35 start of the turnaround motion
that the motion drive error return
to normal in the opposite
direction.

Paper Path Drive

This test moves the gear train in one direction while capturing data, does a reversal to capture
reversal transient data, then operates in the other direction.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Forward Drive Power 1.0 to 4.0 Reports the average drive power
Level (watts) level in the foreword direction.

1 Up Motion Drive 0 to 1.5 Reports the average drive ripple

Error Ripple (watts) level in the forward direction.

2 Reverse Drive -4.0 to Reports the average power in the

Power Level (watts) -1.0 reverse direction.

3 Down Motion Drive 0 to 1.5 Reports the average drive ripple

Error Ripple (watts) in the forward direction.

4 Swing Arm .03 to .06 Reports the time that the lower
Transition Time (sec) portion of the paper path drive is
disconnected while the swing
arm transitions to the other drive
position.

4-36 Phaser 8400/8500/8550 Color Printer

X-Axis Drive
This test drives the X-Axis motor in each directions until the printhead stalls into the stops and
then moves the printhead into the clear and performs an on the fly reversal. The power profile is
used to confirm operational goals.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Right Stall Power 5 to 10 .5 to 3.3 Reports the motor/drive

Level (watts) electronics stall power.
An abnormal level may indicate a
motor/motor drive problem.

1 Left Right Distance 0.32 to -.15 to .5 Reports the distance between

(in) 0.48 the left and right stall points. An
abnormal value may indicate an
problem that restricts the range
of motion (pinched cable, etc.).

2 Right Left Traverse 3.5 to 8.5 .5 to 1.55 Reports the average power
Average Power required to move the printhead
Level (watts) from the right hard stop to the left
hard stop. An abnormal value
may indicate a problem with the
lead screw or printhead bearings
(lubrication, etc.).

3 Right Left Traverse .20 to 1.8 -0.5 to Reports ripple in the power level
Power Ripple (watts) 1.0 needed to move the printhead
from the right hard stop to the left
hard stop. An abnormal value
may indicate a problem with
roughness in the drive
mechanism or an interference
with the printhead motion.

4 Left Right Traverse 4.0 to 8.5 .5 to 1.75 Same as R2 except for the other
Power Average direction of motion.
Level (watts)

5 Left Right Traverse 1.2 to 1.5 -.01 to Same as R3 except for the other
Power Ripple (watts) .05 direction of. motion.

6 Turnaround Power .02 to .11 Reports the width of the

Blip Width (watts) momentary drop in the required
drive power when the printhead
motion is being reversed. An
abnormal value may indicate an
unusual amount of play in the
drive mechanism.

General Troubleshooting 4-37

Transfix Drive Slow and Transfix Drive Fast
With the drum turning at a constant velocity, the transfix roller is loaded against the drum, held for
one revolution, then raised. The velocity with which the transfix roller is moved differs for the two
tests.

Typical Value
R# Definition Fast Slow Actions

0 Time to first 0.22 to 0.22 to Reports the time from the load command
contact (sec) 0.29 0.50 to the engine until the drum indicates
contact with the pressure roller.

1 Loaded 2600 to 2600 to Reports the average Y-axis following error

average Y- 4200 3400 during the Roll With Transfix Roller Down
axis following interval.
error (mpts)

2 Loaded Y- 75 to 150 to Reports the difference between the max

axis following 1200 1100 and min Y-axis following errors during the
error ripple Roll With Transfix Roller Down interval
(mpts)

3 Time to last .300 to 0.30 to Reports the time from the unload
contact (sec) 0.450 0.80 command to the engine until the drum
indicates no further contact.

4-38 Phaser 8400/8500/8550 Color Printer

Drum Maintenance Drive
With the Y-axis rotating, the drum maintenance unit is loaded against the drum for a short time in
each configuration (roller and blade/blade only)

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Time to blade first .01 to .35 .15 to .4 Reports the time from the load
contact (sec) command to the engine until the
drum indicates blade contact.

1 Time to roller first .03 to 045 .2 to .50 Reports the time from the load
contact (sec) command to the engine until the
drum indicates roller contact.

2 Roller/Blade loaded -700 to -650 to Reports the average Y-axis

average Y-axis -250 -150 following error during the Roll
following error With Both Loaded interval.
(mpts)

3 Roller/Blade loaded -50 to 0 to 600 Reports the difference between

Y-axis following error 300 the max and the min Y-axis
ripple (mpts) following error during the Roll
With Both Loaded interval.

4 Roller Average 50 to -.05 to Reports the average period of

Period (sec) 1600 .05 the Y-axis following error ripple
during the Roll With Both Loaded
interval. This variation would be
due to the dmu roller rolling
along the drum surface.

5 Roller Revs 3 to 40 Reports the number of Y-axis

following error ripple peaks
during the Roll With Both Loaded
interval.

6 Roller Disengaged -0.001 to -.05 to Reports the time from the unload
Time (sec) 0.05 0.5 roller command to the engine
until the drum indicates no
further roller contact.

7 Blade loaded -160 to -800 to Reports the average Y-axis

average Y-axis -50 -100 following error during the Roll
following error With Blade Loaded interval.
(mpts)

8 Blade loaded Y-axis -0.001 to 115 to Reports the difference between

following error ripple 0.50 900 the max and the min Y-axis
(mpts) following error during the Roll
With Blade Loaded interval.

General Troubleshooting 4-39

Drum Maintenance Drive (Continued)
With the Y-axis rotating, the drum maintenance unit is loaded against the drum for a short time in
each configuration (roller and blade/blade only)

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

9 Blade Disengaged -0.05 to Reports the time from the unload

Time (sec) 0.05 blade command to the engine
until the drum indicates no
further blade contact.

Tilt Drive
This test drives the printhead tilt mechanism through one cycle to determine if it is controllable
and operating as expected.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Tilt Engage Cap 10 to 600 50 to 550 Reports the distance from the
Position (min) cap Home position to the tilt cam
engage point.

1 Pre Standby Peak 325 to -125 to Reports the distance around the
Location () 3100 10 tilt cam from the tilt engage
position to the pre standby peak.
Should be in degrees, but
currently units/scaling are
unverified.

2 Pre Standby peak -5100 to -150 to Reports the pm motor following

Magnitude (pm ticks) -500 -20 error at the pre standby peak
location.

3 Post Wipe Peak 1400 to -450 to Reports the distance around the
Location () 4150 150 tilt cam from the tilt engage
position to the post wipe peak.
Should be in degrees, but
currently units/scaling are
unverified.

4 Post Wipe peak -4000 to -130 to Reports the pm motor following

Magnitude (pm ticks) -75 25 error at the post wipe peak
location.

4-40 Phaser 8400/8500/8550 Color Printer

Tray 2, Tray 3, Tray 4, Lift Plate Drive
This test raises the lift plate to verify motion and sensor operation. If the test is requested for a
525-sheet feeder that is not installed, an “Option Not Detected” message is generated.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Tray Configuration Reports the tray status (present,

plate not lifted, etc.). See Paper
Path Status test for a description
of the configuration encoding.

1 Start Peak Power Reports the highest peak during

(watts) the first quarter of the lifting
interval.

2 Slack Take-up Time Reports the interval between the

(sec) initial power min (when the plate
is not yet engaged), and the point
where the lifting power becomes
a constant.

3 Average Lift Power Reports the average power over

(watts) the center ¾ of the lifting interval.

4 Lift Contact Time Reports the interval from the

(sec) motor start time until the required
lift power starts to increase due
to the initial contact with the
nudger roller assembly.

5 Lift Time (sec) Reports the interval from the

motor start time until plate lifted
is indicated.

6 Stall Power (watts) Reports the average stall power

during the overlifting interval

General Troubleshooting 4-41

Check Drum Menu

Y-axis Encoder
Uses the sine and cosine sum data to determine the characteristics of the encoder disk and
encoder sensors.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Sin Sum Data Offset 150000 to -68000 to Reports average of the max and
(sin sum units) 800000 160000 min Sin Sum average amplitude
values.
1 Sin Sum Data -11000 to -68000 to Reports difference between the
Amplitude (sin sum 350000 160000 max and min Sin Sum average
units) amplitude values.

2 Amplitude Ripple 25 to 75 2.0 to 12 Reports the ripple in the Sin Sum

(Sun Sum units) amplitude values. Excludes the
neighborhood of the Home notch
(a distance of +/- 50 samples
from the Home notch min
location.

3 Max Position Ripple -140000 24000 to Reports the max variation in the
(mpts) to 275000 52000 reported delta position between
samples over the revolution.

4 Sin max delta -.3 to 5 -.3 to 5 Reports the max value of the
position diference between the rotation
position of any adjacent sin sum
peaks
5 Home Notch Depth 0 to 13 68 to 80 Reports the ratio between the
Ratio (none) notch bottom amplitude and the
max amplitude value as reflected
in the Sin Sum data.

6 Home Notch Width 50 to 90 720 to Reports the width of the Home

(sec) 960 notch at 99% full depth as
reflected in the Sin Sum data.

7 Home Notch 250 to 35 to 65 Reports the ratio of the Home

Symmetry (none) 550 notch width sections as bisected
by a vertical from the notch min
as reflected in the Sin Sum data.

8 Cosine Sum Data 90000 to -125000 Reports average of the max and
Offset (cosine sum 450000 to 200000 min Cosine Sum average
units) amplitude values.

9 Cosine Sum Data 300000 to 300000 to Reports difference between the

Amplitude (cosine 500000 500000 max and min Cosine Sum
sum units) average amplitude values.

4-42 Phaser 8400/8500/8550 Color Printer

Y-axis Geometry
Rotates the drum at a constant velocity and samples the Y-axis position. Uses the data to
determine Y-axis motor and drum vibration and the most significant other vibrational frequencies.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Drum Normalized -3900 to Reports the normalized FFT

FFT Power (none) 6000 power amplitude of the drum
frequency. The normalized value
is generated by dividing the drum
FFT power by 1.0xE13.

1 Drum Frequency 1.25 to Reports the current drum

(hz) 7.5 frequency.

2 Motor FFT Power -200 to Reports the ration of the FFT

Ratio (none) 250 power amplitude of the motor
frequency to the FFT power
amplitude of the drum frequency.

3 Motor Frequency 44 to 48 Reports the current motor

(hz) frequency.

4 FFT Power Ratio 1 -20000 to Reports the ratio of the FFT

(none) 25000 power amplitude of the most
powerful FFT frequency (not
including the drum or motor), to
the FFT power amplitude of the
drum frequency.

5 Frequency 1 45 to 110 Reports the frequency of the

Frequency (hz) most powerful FFT frequency
(not including the drum or motor).

6 FFT Power Ratio 2 -14000 to Reports the ratio of the FFT

(none) 17000 power amplitude of the second
most powerful FFT frequency
(not including the drum or motor),
to the FFT power amplitude of
the drum frequency.

7 Frequency 2 -70 to Reports the frequency of the

Frequency (hz) 140 second most powerful FFT
frequency (not including the
drum or motor).

General Troubleshooting 4-43

Y-axis Drive
This procedure performs a “4 corner” test using the minimum and maximum velocity and
acceleration used during printing and minimum and maximum load for a total of eight test cycles.
Measures servo response parameters under various conditions.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 HAHVN CCW 4000 to 4000 to Reports average following error

Average Fe (mpts) 5700 5800 during the last half of the first
period.

1 HAHVN CCW Fe 100 to 0 to 500 Reports following error ripple

Ripple (mpts) 380 during the last half of the first
period.

2 HAHVN CW -5200 to -5500 to Reports average following error

Average Fe (mpts) 3800 -4000 during the last half of the second
period.

3 HAHVN CW Fe 80 to 380 75 to 350 Reports following error ripple

Ripple (mpts) during the last half of the second
period.

4 HAHVN Start Fe 0.08 to .05 to 0.2 Reports the time following the
Settle time (sec) 1.0 start of motion that it takes the
following error value to enter the
CCW ripple band.

5 HAHVN Reverse Fe 0.17 to .12 to .3 Reports the time following the

Settle time (sec) 1.1 start of motion reversing that it
takes the following error value to
enter the CW ripple band.

6 HAHVN Stop Fe -.001 to -.001 to Reports the time following the

Settle time (sec) 0.15 .30 start of motion stopping that it
takes the following error value to
enter the idle ripple band.

7 HAHVN Delta Print 0.02 to 0 to .11 Reports the time following the
Velocity Settle Time 0.10 start of motion that it takes the Y-
(sec) axis delta velocity to enter the
CCW delta velocity ripple band.

4-44 Phaser 8400/8500/8550 Color Printer

Y-axis Belt Slip
This test does a chase using a special sheet of preprinted media and records the y-axis following
error.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Initial Peak Y-axis 0 to 1200 to Reports the amplitude of the first

FE (mpts) 12000 8000 Y-axis following error peak.

1 Max Following Peak 0 to 1100 to Reports the amplitude of the

Y-axis FE (mpts) 11000 7500 maximum Y-axis FE peak after
the first.

2 Average Y-axis FE 0 to 4000 2200 to Reports the average of the Y-axis

(mpts) 3500 following error during the roller
down portion of the transfix
operation.

Y-axis Belt Tension

This test modifies the y-Axis servo loop so that it is unstable and oscillates. The oscillation
frequency is recorded while the drum is advanced for two revolutions. Checks for correct belt
tension and for variations in tension during operation.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Min Resonant 10 to 150 4.5 to 175 Reports the min resonant

Frequency (hz) frequency over the data set.

1 Max Resonant 175 to -4400 to Reports the max resonant

Frequency (hz) 3000 10000 frequency over the data set.

2 Min Resonant Reports the number of full Y-axis

Frequency Revs revs required to locate the min
(revs) frequency configuration.

3 Min Resonant -0.001 to -33 to -20 Reports the amount of additional

Frequency Angle -0.2 Y-axis rotation required to locate
(deg) the min frequency configuration.

General Troubleshooting 4-45

Stripper Contact
This test holds the drum stationary while the stripper solenoid is activated and released. The
drum servo error signal illustrates activation/deactivation timing and how strongly the drum was
contacted by the blade.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Engage -10 to 2 -15 to 8.0 Reports the static difference

Displacement (mpts) between the average ya_fe
before and after the blade
contacts the drum, indicating how
strongly the blade is interacting
with the drum while pushing onto
the drum.
May be an indication as to the
condition of the blade (stiffness,
dirty, bent, delaminated, etc.).
Another potential factor could be
the solenoid range of travel or
engagement force (solenoid/
solenoid drive strength or return
spring strength).

1 Engage Time (sec) .0030 to 0 to .05 Reports time between

.0035 engagement of the stripper
solenoid and initial contact
between the blade and the drum.
May indicate the geometry of the
mechanism, such as parts out of
tolerance, mis-assembled, or
bent, causing an incorrect blade
to drum gap.

2 Engaging Period 0 to 0.11 0 to .3 Reports time between stripper

(sec) solenoid engagement and the
point when the reaction of the
drum to the contact of the blade
fades back into the ripple (noise).
Another indication of blade to
drum interaction. The profile
shape (R2/R2) could be a
dynamic indication of the blade/
drum interaction as is the static
value reported by R0.

3 Engaging Amplitude 3 to 18 5.0 to 35 Reports the magnitude of the

(mpts) reaction of the drum to the
contact of the blade. (See R2)

4-46 Phaser 8400/8500/8550 Color Printer

Stripper Contact (Continued)
This test holds the drum stationary while the stripper solenoid is activated and released. The
drum servo error signal illustrates activation/deactivation timing and how strongly the drum was
contacted by the blade.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

4 Release -0.75 to -4.5 to Reports the static difference

Displacement (mpts) 2.2 4.5 between the average ya_fe
before and after the blade
disengages from the drum,
indicating the strength of the
blade/drum interaction while
pulling off the drum (see R0).

5 Release Time (sec) 0 to 0.09 .002 to .1 Reports the time between the
disengagement of the stripper sol
and the point when the blade
begins to withdraw from the drum
(see R2).

6 Releasing Period 0 to .001 -0.5 to Reports the time between the

(sec) .75 disengagement of the stripper sol
and the point when the reaction
of the drum to the withdrawal of
the blade fades back into the
ripple (see R2).

7 Releasing Amplitude -45 to 0 -10 to 1 Reports the magnitude of the

(mpts) reaction of the drum to the blade
withdrawal (see R3).

Drum Maintenance Contact

This test uses the drum servo error signal to indicate when the drum is contacted by the roller
blade.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Initial Contact Reports the distance the pm

Position (pm motor motor was moved (raising the dm
counts) unit), before a Y-axis reaction was
detected. Shows that the dm is
raising, provides blade/drum gap
information.

General Troubleshooting 4-47

Check Motors Menu

Y-Axis Motor
This test turns on the Y-axis motor and runs it very slowly for one revolution.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Motor fe ripple 0.08 to .07 to .7 Reports amount of variation of

(ticks) 0.60 the motor following error over the
recording interval.

1 Motor fe average 0.5 to 0.7 .5 to .8 Reports the motor following error

(ticks) average value of the recording
interval.

2 Motor drive voltage 0.34 to .3 to 1.5 Reports amount of variation of

ripple (volts) 1.3 the motor drive voltage over the
recording interval.

3 Motor drive voltage -1.4 to -1.6 to -.8 Reports average value of motor
(volts) -0.8 drive voltage over the recording
interval.

4 Motor drive power 0.25 to .06 to .13 Reports variation of motor drive
ripple (watts). 1.8 power over the recording interval.

5 Motor drive power 1.25 to 1.3 to 2.5 Reports average value of motor
average (watts) 2.6 drive power over the recording
interval.

X-Axis Motor
This test turns on the X-axis motor and runs it very slowly for one revolution.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Motor Voltage A 84 to 86 59 to 62 Reports amount of variation of

Ripple (volts). the motor phase A drive voltage
over the recording interval.

1 Motor Voltage A -0.120 to .10 to .05 Reports the motor phase A drive
Average (volts) 0.13 voltage average value over the
recording interval.

4-48 Phaser 8400/8500/8550 Color Printer

X-Axis Motor
This test turns on the X-axis motor and runs it very slowly for one revolution.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

2 Motor Voltage B 84 to 86 59 to 62 Reports amount of variation of

Ripple (volts) the motor phase B drive voltage
over the recording interval.

3 Motor Voltage B -.012 to .04 to .11 Reports the motor phase B drive
Average (volts) 0.1 voltage average value over the
recording interval.

4 Motor Drive Power 0.5 to 2.0 .1 to .5 Reports amount of variation of

Ripple (watts) the motor drive power over the
recording interval.

5 Motor Drive Power 9 to 13 5.5 to 7.5 Reports the motor drive power
Average (watts) average value of the recording
interval.

Process Motor
This test turns on the process motor and runs it very slowly for one revolution.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Motor fe ripple 2.8 to 6.0 0 to .02 Reports amount of variation of

(ticks) the motor following error over the
recording interval.

1 Motor fe average -4 to 3.0 .015 to Reports the motor following error

(ticks) .01 average value of the recording
interval.

2 Motor drive voltage 5 to 11 8 to 11 Reports amount of variation of

ripple (volts) the motor drive voltage over the
recording interval.

3 Motor drive voltage 1.3 to 2.3 .9 to 1.5 Reports the motor drive voltage
(volts) average value of the recording
interval.

4 Motor drive power 1.03 to .7 to 2.0 Reports amount of variation of

ripple (watts) 3.6 the motor drive power over the
recording interval.

General Troubleshooting 4-49

Process Motor
This test turns on the process motor and runs it very slowly for one revolution.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

5 Motor drive power 1.5 to 3.5 1.2 to Reports the motor drive power
average (watts) 2.75 average value of the recording
interval.

Media Path Motor

This test turns on the media path motor and runs it very slowly for one revolution.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Motor fe ripple .40 to 1.3 .001 to Reports amount of variation of

(ticks) .0035 the motor following error over the
recording interval.

1 Motor fe average 0.8 to 2.0 .0033 to Reports the motor following error
(ticks) .007 average value of the recording
interval.

2 Motor drive voltage 4 to 10 4 to 8 Reports amount of variation of

ripple (volts) the motor drive voltage over the
recording interval.

3 Motor drive voltage -5.5 to - -5 to -2.0 Reports the motor drive voltage
(volts) 2.0 average value of the recording
interval.

4 Motor drive power 0.8 to 6 .8 to 3.9 Reports amount of variation of

ripple (watts) the motor drive power over the
recording interval.

5 Motor drive power 1.9 to 7 2 to 8 Reports the motor drive power

average (watts) average value of the recording
interval.

4-50 Phaser 8400/8500/8550 Color Printer

Tray 2, Tray 3, Tray 4, Lift Motor
his test turns on the specified motor and runs it at constant velocity for approximately 20
revolutions while recording drive data. The test is the same for each motor. Requesting a test for
a 525-sheet feeder that is not installed will generate an “Option Not Detected” message.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Motor Peak Power 1 to 2.5 Reports max amount of motor

(watts) power over the run interval.

1 Motor Average .25 to .55 Reports the average motor drive

Power (watts) power over the last half of the run
interval.

2 Brake Average .10 to .20 Reports the average motor brake

Power (watts) power over the stop with brake
interval.

Tray 3 and Tray 4 Pick/Feed Motor

This test turns on the specified motor and runs it at constant velocity for approximately 25
revolutions while recording drive data. The test is the same for each motor. Requesting a test for
a 525-sheet feeder that is not installed will generate an “Option Not Detected” message.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Motor fe ripple Reports amount of variation of

(ticks) the motor following error over the
recording interval.

1 Motor fe average Reports the motor following error

(ticks) average value of the recording
interval.

2 Motor drive voltage Reports amount of variation of

ripple (volts) the motor drive voltage over the
recording interval.

3 Motor drive voltage Reports the motor drive voltage

(volts) average value of the recording
interval.

4 Motor drive power Reports amount of variation of

ripple (watts) the motor drive power over the
recording interval.

General Troubleshooting 4-51

Tray 3 and Tray 4 Pick/Feed Motor (Continued)
This test turns on the specified motor and runs it at constant velocity for approximately 25
revolutions while recording drive data. The test is the same for each motor. Requesting a test for
a 525-sheet feeder that is not installed will generate an “Option Not Detected” message.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

5 Motor drive power Reports motor drive power

average (watts) average value over the recording
interval.

4-52 Phaser 8400/8500/8550 Color Printer

Check Misc Menu

Paper Path Status

This test looks at the paper path sensors to identify if anything would prevent a page from
printing. The Control Panel will display messages indicating if anything unexpected is found for:
R0 = upper paper path; R1 = tray 1; R2 = tray 2; R3 = tray 3; and R4 = tray 4. The display is a
string of 0’s and 1’s (one digit for each sensor state) and is listed below from most significant bit to
least significant bit.
1 = an item that needs to be corrected.
0 = normal

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Upper Paper Path 6 -31 Not used, always 0

0 5 - Front door open

0 4 - Top door open

0 3 - Paper at deskew sensor

0 2 - Paper at preheat exit sensor

0 1 - Paper at strip sensor

0 0 - Paper at exit sensor

1 Tray 1 14 - 31 unused, always 0

1 13 - No media present

1 0 - 12 width value

2, 3, Tray 2, Tray 3 and 9 - 31 unused

4 Tray 4

2, 3, 8 - No tray
4

2, 3, 7 - No paper
4

2, 3, 6 - plate not lifted

4

2, 3, 5 - Paper at tray pick sensor

4

2, 3, 4 - media length top

4

General Troubleshooting 4-53

Paper Path Status (Continued)
This test looks at the paper path sensors to identify if anything would prevent a page from
printing. The Control Panel will display messages indicating if anything unexpected is found for:
R0 = upper paper path; R1 = tray 1; R2 = tray 2; R3 = tray 3; and R4 = tray 4. The display is a
string of 0’s and 1’s (one digit for each sensor state) and is listed below from most significant bit to
least significant bit.
1 = an item that needs to be corrected.
0 = normal

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

2, 3, 3 - media length bottom

4

2, 3, 2 - Media width top

4

2, 3, 1 - media width middle

4

2, 3, 0 - Media width bottom

4

Temperature Status
This test scans the thermocouples and reports data on the current temperature with the goal of
providing a picture of the current temperature state of the printer. All degrees are reported in
celsius.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Reservoir Temp ~127.7o ~135.0o Reports the current temperature

1 Left Jetstack ~134o ~138o Reports the current temperature

2 Right Jetstack ~134o ~138o Reports the current temperature

3 Preheater Temp ~62o ~70 Reports the current temperature

4 Drum Temp ~60o ~60o Reports the current temperature

5 Ink Melt 1 Temp ~50o ~50o Yellow (usually off)

6 Ink Melt 2 Temp ~50o ~50o Cyan (usually off)

7 Ink Melt 3 Temp ~50o ~50o Magenta (usually off)

4-54 Phaser 8400/8500/8550 Color Printer

Temperature Status (Continued)
This test scans the thermocouples and reports data on the current temperature with the goal of
providing a picture of the current temperature state of the printer. All degrees are reported in
celsius.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

8 Ink Melt 4 Temp ~50o ~50o Black (usually off)

Purge Pump
This test determines if the purge pump system (pump/hose/purge valve/printhead) is operating
normally.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 Jetstack ~134o ~138o Reports current jetstack

Temperature (deg) temperature. If the temperature is
above current threshold (120
deg), the test will abort and
following results will report as 0.
This avoids having ink extrude
out of the faceplate and onto the
drum, requiring both a wipe and a
chase to clean up.

1 Start Power (watts) Reports initial peak pumping

power after pump power on. This
reflects the inrush current to the
pump motor. An unusual value
could indicate a defective motor
(windings/brushes/etc.).

2 Initial Pumping Reports minimum pumping

Power (watts) power after start up peak (R1).
This is the first value to reflect the
system pressure. If the volume is
normal (hose/printhead), then the
drop is large and the pressure
rises slowly. If the volume is small
(hose pinched plugged near the
pump), then the drop is minimal
and the pressure rises quickly

General Troubleshooting 4-55

Purge Pump (Continued)
This test determines if the purge pump system (pump/hose/purge valve/printhead) is operating
normally.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

3 Max Pressure Reports average pumping power

Pumping Power just before maximum pressure is
reached. May indicate the
efficiency of the pump, leaks,
and/or the setting of the pressure
relief valve.

4 Pumping Time To Reports the time from pump on

Max (sec) until the pressure relief valve
opens. May indicate the
conditions discussed in R3, as
well as the system volume.

5 No Pressure Reports the average pumping

Pumping Power power after the pressure has fully
(watts) decayed. May indicate pump
motor condition/efficiency.

6 Pressure Decay Reports the time between purge

Time (sec) valve opening and the point when
the pumping power (relative to
the current pressure), fades back
into the ripple of the no pressure
pumping power (see the R5
discussion above). This time
could indicate the operation of
the purge valve and the condition
of the bleed orifice (plugged,
etc.).

Voltages
This test determines averaged readings for key system voltages.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

Main Board Voltages

0 5 Volts (volts) ~5V ~5V

1 1.8 Volts (volts) ~1.8V ~1.8V

4-56 Phaser 8400/8500/8550 Color Printer

Voltages (Continued)
This test determines averaged readings for key system voltages.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

2 2.5 Volts (volts) ~2.5V ~2.5V

3 3.3 Volts (volts) +/-2.5% +/-2.5%

4 unregulated12 Volts +/- 20% +/- 20%

(volts)

5 2.5 Volts (volts) ~ 2.5 ~ 2.5

6 unregulated +/- 20% +/- 20%

Negative 12 Volts
(volts)

Control Board Voltages

7 DC Power (watts)

8 50 Volts 47 to 52 47 to 52

9 Negative 50 Volts -47 to 52 -47 to 52

10 Unregulated -11 to - -11 to -

Negative 15 Volts 16.5 16.5

11 Unregulated 15 Volts 11 to 17 11 to 17

12 AC Volts 120 Volts 90 to 140 90 to 140

AC Volts 240 Volts 180 to 180 to

275 275

Wiper Alignment

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 The engage wiper 50 to 400 Reports the distance from wipe

position (min) home to the tilt engage position.

1 Upper hard stop 2000 to Reports the distance from wipe

wiper position (min) 5000 to home to the upper hard stop.

General Troubleshooting 4-57

Drum Maint/Transfix Home
This test drives the process motor a short distance in each direction to verify that the dmfix drive
unit was in its home position.

Typical Typical
Value Value
(8400) (8500/
R# Definition 8550) Actions

0 DM Initial FE Peak Reports the height of the initial

(pm motor counts) peak when starting rotation of the
dm drive gear.

1 DM Initial FE Peak Reports the time since the start

Time (sec) of CCW motion until the peak
was detected.

2 TF Initial FE Peak Reports the height of the initial

(pm motor counts) peak when starting rotation of the
tf drive gear.

3 TF Initial FE Peak Reports the time since the start

Time (sec) of CW motion until the peak was
detected.

4-58 Phaser 8400/8500/8550 Color Printer

Electronics Troubleshooting

Printer Power-Up Sequence

The following lists the chain of events that occur when you turn on a printer. You can
follow this list as one means of determining if the printer is operating correctly. The
exact chain of events depends upon the last power down condition and where the
printer has last determined the printhead is positioned, this is stored in non-volatile
RAM. The Electronics Troubleshooting Checklist is the primary reference for
troubleshooting power-up problems.
1. Power cord is plugged in and the power switch is turned on:
2. Power supply senses AC line voltage conditions (110 VAC or 220 VAC) and
enables DC voltages. If an overload occurs, the printer turns off the high voltage
DC supplies, causing a “blink” effect on the Control Panel LEDs.
3. BIST test flashes the PE LED very briefly at a fast rate until the end of the next
test.
4. The Boot loader performs CPU initialization and RAM test. It then sends the
boot loader version to the serial port.
5. Power-On Self Test (POST) initializes the Control Panel. The Control Panel LED
turns red, green, orange, and then off. The Control Panel LCD then goes black
and then clear. The POST version displays on the LCD and waits two seconds.
During this time the operator can press the Back button to bypass the remaining
POST test.
6. Low level Power-On Self Test (POST) diagnostics are performed. The Control
Panel displays status messages as each sub-test is performed. This test takes
about 8 seconds. All LEDs are off during the test.

If POST diagnostics pass, the Control Panel displays the Xerox logo and turns on
the green LED.

If the test detects an error, the error message displays on the LCD and the printer
flashes the LEDs with a repeating error code pattern.
7. The VxWorks operating system is initialized and engine code is started. This
takes about 15 seconds. The Xerox logo is displayed.
8. Print Engine Self Test (PEST) diagnostics are then performed. These test the
heaters, clutches, motors and solenoids. As each clutch is tested, you hear
clicking with four high tones as each motor is tested. This test takes about 30
seconds.
9. The printer now runs the mechanical initialization. The exact sequence depends
on the initial position of the printhead and wiper assembly.

General Troubleshooting 4-59

 Start Mechanical Mechanical Recovery

4-60
Recovery POWER ON

Set FIRMWARE states:

CapState = UNKNOWN Values in the NVRAM are used to
Start the Thermals Head Tilt State = UNKNOWN determine if printhead and wiper have
13,xxx DmfixState = UNKNOWN contact or if the head was parked on
YaState = HOMELESS
Xa State = HOMELESS last power down. If printhead and wiper
are in contact, the printhead warms
Unbind Media first before moving. If the printhead
Path Motor and
Home the MPT Home the Y-Axis was parked, the printhead is warm
31,000 5001, 5004 before moving to the print position.
The dashed line traces what happens
Wait for the Head if the printhead was parked on last
to read
Is the head tilt power down.
OK_TO_WIPE YES
Temperatures Cam engaged The RED numbers indicate errors that
13.xxx (head tilted?)
may be displayed at that point in the
Mechanical Initialization (8400)

mech init process.

Home XA
NO
6000

Home the CAP/wiper

without disengaging the
Move XA to Head Tilt Cam
HEAD TILT 8005, 8007, 8008, 8009
POSITION
6000

s8500-029

Phaser 8400/8500/8550 Color Printer

 RECOVERY ROUTINE
YES

Did the
Home Dmfix Process Motor YES
_head Parked On? NO 7002 Devise Fault?
Last Power Down? Try to recover
from Process
NO Motor Stall

General Troubleshooting
YES Move Head to the Home XA
Standby position. 6000
7007, 7008, 8005, 8055, 8007,
Move Cap/Wiper 7006, 8008, 8009
to the Park
ARMS- and restrain Move XA to Left
head again. Move XA to Left Side Hard Stop
8035,7009 Side Hard Stop 6000 Jog the X
6000 Axis in
order to
Jog the X NO Move XA to Tilt release the
Device Fault Codes Axis in Move XA to Tilt Head Tilt
Position Position
80xx - Wiper order to 6000 Arms.
7002 - PM stalled release the 6000
70xx - Headtilt Head Tilt
7014 - Head Not Restrained Arms. Move Head to the
31001 - Media Path Home/ Print home Dmfix
5001 - YA Home Timer position again
Move Head to the 4025
5002 - YA Encoder (Stall) 7010, 7006
PARK position,
6000 - XA Error
7007, 7008, 8005, 8055, 8007,
4025 - PM Init Failed
7006, 8008, 8009, 7014 Start YA Slew
(home Dmfix)
5003
4024 - Wiper Alignment Failed
8021 - Pump Uninitialized Warmup will be responsible for
If not in non-thermals moving the head to the print position
Oil Drum 4 times Rehome XA
6000 after the wipe and purge are
Others..... - Thermal Faults,
performed.
ECM Faults, HC, PM Faults
oiling drum DONE
s8500-030

4-61
4-62
Mechanical Recovery
POWER ON
MECHANICAL RECOVERY Start Mechanical
Recovery

Start the Set FIRMWARE states:

thermals. CapState = UNKNOWN
13,xxx Values in NVRAM are used to determine if
HeadTiltState = UNKNOWN printhead and wiper have contact or if the
DmfixState = UNKNOWN printhead was parked on last power down. If
YaState = HOMELESS printhead and wiper are in contact, the printhead
Close preheater
Unbind Media warms first before moving the wiper.
Path Motor and The BLUE line traces what happens if printhead
HOME the MPT was parked on last power down.
31,001 NOTE: Headtilt CAM will be engaged when the
Home the Y-Axis printhead is in the PARKED (restrained) position.
5001, 5004 The RED numbers indicate errors that may be
Wait for head to read displayed at that point in the process.
OK_TO_WIPE
temperatures
13,xxx Is the
Yes head tilt CAM
engaged
Home XA and move XA to the (head tilted?)
HEADTILT position
6000
No
Mechanical Initialization (8500/8550)

Engage the Headtilt

Solenoid Use the Headtilt
Solenoid and tilt the Home the CAP/wiper
head to Standby without disengaging the
7007, 7006, 7008, 8005, Head Tilt CAM
8055, 8007, 8008, 8009 8005,
Move the wiper and the head to determine if 8007, 8008, 8009
the head is fully restrained or not. This will
allow the head to tilt to the standby position so
the wiper can be homed.
7007, 7006
s8500-137

Phaser 8400/8500/8550 Color Printer

 Yes
_headParkedOn
Move Cap/Wiper to the PARK LastPowerDown?
ARMS - and restrain head
again. Yes
8035, 7009 No
RECOVERY ROUTINE
Try to recover from
Did Process Motor Stall
homeDmfix the Process Motor
7002 Device Fault? Yes

General Troubleshooting
Home XA
6000
No
Device Fault Codes Move Head to the Move XA to Left
Standby position, Side Hard Stop
80xx - Wiper 7007, 7006, 7008, 8005, 6000
8021 - Pump Not Inited 8055, 8007, 8008, 8009
7009 - Wiper Alignment Jog the X
No Move XA to Tilt Axis in order
7002 - PM stalled Move XA to Left Side Position
70xx - Headtilt to release the
Hard Stop 6000
7006 - Headtilt Solenoid Jog the X HeadTilt
6000
7014 - Head Not Restrained Axis in Arms.
31001 - Media Path order to Move XA to Tilt position homeDmfix
5001 - Ya Home Timer release the 6000 again
5004 YA - General Motion Error HeadTilt 4025
6000 - XA Error Arms. Move Head to the
4025 - PM Init Failed (homeDmfix) Home/Print position
4024 - Wiper Alignment Failed 7006, 7010
Others... - Thermal faults, ECM
Faults, HC, PM faults oiling drum Start YA SLEW
5004

Move Head to the

Rehome XA
PARK position,
6000
7007, 7008, 8005, 8055,
8007, 8008, 8009, 7014

After the printer is warm,

Warmup will be responsible for moving
the head will tilt to the DONE
the head to the print position after the
print position and
wipe and purge are performed.
Oil Drum 4 times

4-63
s8500-138
If the printer was not shutdown by the power switch the last time it
was turned off or it was shutdown with ink on the drum:
1. As soon as the printer has warmed up, the media path motor moves the wiper to
the bottom of its travel and the process motor moves the printhead to the print
position a chase page is sent through the paper path to clean ink from the drum.

If printhead, ink reservoirs, or jetstack temperature are below purge

threshold, the printer performs a head clean cycle.
1. The printer waits for the printhead to reach its purge temperature.
2. The printer moves the wiper to the bottom of its travel and tilts the printhead
forward to its print position to check the ink levels. If the ink level is low, ink is
melted into the appropriated reservoirs.
3. The printhead tilts to the standby position and moves the wiper assembly to the
purge position in front of the printhead faceplate.
4. The purge pump begins the pressure purge after about 2 seconds the purge pump
solenoid opens.
5. The printhead tilts forward against the wiper assembly (wipe position) and the
purge and wipe cycle begins.
6. The Control Panel indicates the printer is performing the cleaning process.
7. The printhead is moved left to the tilt zone, where the printhead can tilt back
without interference, and the media path motor moves the wiper to the bottom of
its travel to engage the printhead tilt cam. The process motor rotates the printhead
tilt gears, which tilt in order to move the printhead to the forward print position.
8. After the print engine is in a known, valid state the Control Panel display shows
the warm-up progress (the Ready LED flashes). When warm-up completes, the
Ready LED displays solid.
9. The temperature of the printhead, drum and paper preheater are allowed to
stabilize at their operating temperatures and ink is melted if needed.
10. The printhead is homed to the print position for printing.
11. A cleaning page is printed at this time, if a purge was performed.
12. A start page is printed (if enabled).
13. The Control Panel displays a message that the printer is initializing and then
ready.
14. The print engine is initialized and is ready to print.

4-64 Phaser 8400/8500/8550 Color Printer

Miscellaneous Electrical Troubleshooting
The electronics module contains the Power Supply, Image Processor board and the
Power Control board. If a component of the electronics module fails, and service is
necessary, the entire electronics module is replaced as a unit. No individual board
troubleshooting is required. The printer contains many self test routines to aid in
diagnosing problems.

Note
If the printer encounters certain fault conditions, the printer may reboot up to
three times before displaying an error code. This is an attempt to correct the
problem and reduce the number of unnecessary service calls.

Following the suggested debug procedures, the specified sequence generally provides
better test coverage than performing tests in a different order.

Error Message Displayed on Control Panel LCD

Printer has detected a fault condition.
1. See "Fault Code Error Message Troubleshooting" on page 3-9 for definitions and
solutions.

LCD Is Blank and the PS and PE Indicators Are Flashing an Error Code
Printer has detected a fault condition but can't display a message on the LCD.
Some portion of the chain of devices used to drive the LCD may be defective
since an error message is not displayed.
1. See "Fault Code Error Message Troubleshooting" on page 3-9 for definitions and
solutions.

Printer Fails to Power-Up: PS, PE and the 3.3 V Indicator LEDs Are Not
Illuminated
1. Printer is not receiving proper AC.

Note
Use caution with hazardous voltages when diagnosing AC problems. The
3.3 V LED is located INSIDE the electronics module and must be observed
through the vent holes close to the AC power switch, see the illustration on
page 4-75.

a. Inspect the power cord.

b. Verify AC outlet voltage and current capacities are within specifications.
c. If necessary, move the printer to a different outlet and retest.

General Troubleshooting 4-65

 2. Transient on AC line tripped protective circuitry in printer power supply.
a. Cycle power to printer to reset protective circuits in power supply.
3. Short circuit on 3.3 V power supply within the electronics module. ESD damage
to the printer may occur if static electricity is discharged to printer electronics
a. With power cord connected, touch the metal electronics module to discharge
any static electricity.
b. Turn off printer and wait 30 seconds for power supply capacitors to
discharge. Damage to circuits within the electronics module may occur if the
power supply capacitors are not allowed to fully discharge.
c. Unplug power cord and remove printer's covers.

Caution
Use caution around motors, pulleys and live AC connections when working
with the printer covers off.

d. Unplug the following electronics module connectors: This step removes all
other circuits so the electronics module can be tested alone.
■ Power Control to I/O board (J800)
■ Power Control right (J400)
■ Preheater solenoid (interconnect cable)
■ Printhead tilt gear solenoid (interconnect cable)
■ Printhead data (J130)
■ Waveamp signal (J790)
■ Power Control left (J390)
■ Y-Axis motor (J280)
e. Plug in power cord and turn on power to the printer
f. If the PE and PS indicators do not flash momentarily, the short is inside the
electronics module. Replace the electronics module and retest the printer. If
PE and PS indicators flash, continue with debug.
g. Plug in all cables removed during service.
h. Trace through all service steps performed to reattach any cables that were
unplugged during debugging.
i. Attach printer covers.
j. Perform full test of printer.
4. Short circuit on 3.3 V power supply within the I/O board.
a. REQURIED: Follow all procedures from Step 3 before proceeding with
these steps. The I/O board needs to be isolated from other systems in the
printer to be effectively tested.
b. Turn off printer and wait 30 seconds for power supply capacitors to
discharge. Damage to circuits within the electronics module may occur if the
power supply capacitors are not allowed to fully.
c. Unplug the Control Panel connector (J220) on the I/O board. This removes
the Control Panel from the I/O board.

4-66 Phaser 8400/8500/8550 Color Printer

 d. Plug in the Power Control to I/O board connector (J800). This step adds the
I/O board back to the working electronics module - nothing else is
connected.
e. Turn on power to the printer
5. If the PE and PS indicators do not flash momentarily, the short is on the I/O board
or related cabling. Skip the rest of this section if the PE and PS indicators flash
because the problem is elsewhere in the printer.
a. Verify short is on the I/O board by using an ohmmeter to check the resistance
on J270, pin 1 to ground. Resistance of less than 1K ohm indicates a
problem.
b. To isolate problem to I/O board or related cabling, unplug I/O board
connectors:
■ Umbilical Right J1
■ Waste Tray Sense J110
■ Stripper Solenoid J250
■ Paper Tray Sense J610
■ Front Door Sense J600
■ Inkload Signal J910
■ DMU Sense J860
■ Drum Thermistor J870
■ Exit Module J680
■ Heater Relay Control J950
c. Retest the resistance of the I/O board. If the resistance is still less than
1K ohm, replace the I/O board, reinstall all cables and retest printer.
d. If the I/O board resistance is OK, plug in the I/O board connectors one at a
time and retest the resistance.
e. Plug in all cables removed during service.
f. Trace through all service steps performed to reattach any cables that were
unplugged during debugging.
g. Attach printer covers.
h. Perform full test of printer.
6. Short circuit on 3.3 V power supply within the Control Panel.
a. REQUIRED: Follow all procedures from Step 3 and Step 4 before
proceeding.
b. With power cord connected, touch the metal electronics module to discharge
any static electricity.
c. Turn off printer and wait 30 seconds for power supply capacitors to
discharge. Damage to circuits within the electronics module may occur if the
power supply capacitors are not allowed to fully discharge.
d. Plug in the Control Panel connector J220 on the I/O board. This step adds the
Control Panel back to a working electronics module and I/O board in order
to see if the short circuit is also removed.
e. Turn on power to the printer.

General Troubleshooting 4-67

 f. If the PE and PS indicators do not flash momentarily, the short is on the
Control Panel. Replace the Control Panel and retest the printer. Skip the rest
of this section if the PE and PS indicators flash because the problem is
elsewhere in the printer.
g. Plug in all cables removed during service.
h. Trace through all service steps performed to re-attach any cables that were
unplugged during debugging.
i. Attach printer covers.
j. Perform full test of printer.
7. Short circuit on 3.3 V power supply within the printhead.
a. REQURIED: Follow all procedures from 'Short circuit on 3.3 V power
supply within the electronics module' before proceeding. The following
procedure relies on a working electronics module to determine if the
printhead is causing a short circuit.
b. With power cord connected, touch the metal electronics module to discharge
any static electricity. ESD damage to the printer may occur if static
electricity is discharged to printer electronics.
c. Turn off printer and wait 30 seconds for power supply capacitors to
discharge. Damage to circuits within the electronics module may occur if the
power supply capacitors are not allowed to fully discharge.
d. Plug in the printhead interface connector (J130) to the electronics module.
This step adds the Control Panel back to a working electronics module
and I /O board in order to see if the short circuit is also removed.
e. Turn on power to the printer.
f. If the PE and PS indicators do not flash momentarily, the short is on the
printhead. Replace the printhead and retest the printer. Skip the rest of this
section if the PE and PS indicators flash because the problem is elsewhere in
the printer.
g. Carefully test the printer to ensure damage to the electronics module did not
occur due to the shorted printhead.
h. Plug in all cables removed during service.
i. Trace through all service steps performed to reattach any cables that were
unplugged during debugging.
j. Attach printer covers.
k. Perform full test of printer.

4-68 Phaser 8400/8500/8550 Color Printer

Printer Is On and Can Print Pages, but the Control Panel Appears
Frozen and No Error Messages Are Displayed

Note
Opening and closing the front door of the printer causes a reset of the entire
Control Panel.

1. Electrostatic Discharge.
a. If the printer is currently powered on and frozen, open then close the front
door of the printer and see if the LCD responds.
b. If printer appears functional after operating the door, advise client that
failure may have been due to an ESD event. Thoroughly test printer for any
other problems.
c. Skip the rest of this section if printer now appears functional, otherwise
continue debugging.
d. With power cord connected, touch the metal electronics module to discharge
any static electricity. ESD damage to the printer may occur if static
electricity is discharged to printer electronics.
e. Turn off printer and wait 30 seconds for power supply capacitors to
discharge. Damage to circuits within the electronics module may occur if the
power supply capacitors are not allowed to fully discharge.
f. Unplug power cord and remove printer's covers. Use caution around motors,
pulleys and live AC connections when working with the printer covers off.
g. Examine printer for loose grounding connections, especially the ground
strap on the Y-axis motor. Eliminate the possibility of internally generated
ESD from affecting printer.
h. Plug in all cables removed during service. Trace through all service steps
performed to reattach any cables that were unplugged during debugging.
i. Attach printer covers.
j. Perform full test of printer.
2. Control Panel failure
a. Unplug the original Control Panel at connector ('C' / J220) and plug in a
known working Control Panel. This step checks for a keypad or LCD failure
in the Control Panel.
b. Plug in all cables removed during service. Trace through all service steps
performed to reattach any cables that were unplugged during debugging.
c. Attach printer covers.
d. Perform full test of printer.

General Troubleshooting 4-69

Printer Control Panel Is Functional, but Printer Won't Print Jobs Sent
from Computer
1. Computer driver incorrect or improperly installed
a. Verify printer hardware is functional by sending a test print via the printer
Control Panel.
b. If a test print is properly produced, continue to next steps, focusing on
problems outside the printer (network, Ethernet, or computer driver
configuration issues).
c. If a test print is not properly produced, the focus of problems within the
printer suggests that the internal settings are corrupt.
d. Use a known functional computer to test printer using the printer's parallel
port or USB port. If test computer successfully prints pages, review the
version of driver, the installation and the settings of the customer's computer.

Note
Using the parallel or USB port eliminates any network complexities
associated with an Ethernet port.

e. If test computer is unsuccessful, continue with debug.

2. Customer network or printer's Ethernet port not properly configured.
a. Please see "Testing Communications Ports" on page 4-82 for procedures
related to communication problems.
3. Disconnect the printer from its network and see if the behavior continues.
4. Printer internal settings corrupted.
a. On the Control Panel, use the Hidden Service Menu to reset NVRAM.
b. Perform full test of printer.

Printer Resets Unexpectedly

1. Transient on AC line tripped reset circuitry in printer.
a. Cycle power to ensure printer initializes during stable AC power.
2. Internal fault
a. Record any error codes and report to Xerox Office Group. If the printer
detects an error, the printer will attempt to reboot and re initialize (up to
three times) to correct the problem. After the third cycle of rebooting, an
error code displays on the LCD and flashes on the PS and PE indicators.
3. Disconnect the printer from its network, for a few hours if necessary, to see if the
behavior continures.

4-70 Phaser 8400/8500/8550 Color Printer

Printer Fails to Enter ENERGY STAR Mode
1. Model not certified as an ENERGY STAR model.
a. Use the Control Panel to enable Energy Star mode (Printer Setup -> Printer
Control -> Select Power Saver Timeout). Some printers are not shipped as
energy star compliant and don't have the power saving mode enabled by
default.
2. Electronics module failure.
a. REQUIRED: Follow all procedures from 'Model not certified as an Energy
Star model' before proceeding.
b. With power cord connected, touch the metal electronics module to discharge
any static electricity.
c. Turn off printer and wait 30 seconds for power supply capacitors to
discharge.
d. Unplug power cord and remove printer's covers.
e. Replace the electronics module.
f. Plug in all cables removed during service.
g. Trace through all service steps performed to reattach any cables that were
unplugged during debugging.
h. Attach printer covers.
i. Perform full test of printer.

Printer Reports Missing Maintenance Kit

1. Maintenance kit missing or not fully seated.
a. Fully install maintenance kit.
2. Connector not fully seated.
a. Check I/O board connector J860 for proper mating.
3. Ensure that the waste tray sensor is incorrectly installed at the end of the waste
tray housing.

Printer Reports Missing Waste Tray

1. Waste tray missing or not fully seated.
a. Fully install waste tray.
2. Connector not fully seated.
a. Check I/O board connector J110 for proper mating.

General Troubleshooting 4-71

Printer Optional Features Not Available
1. Printer configuration incorrect.
a. Verify proper configuration of printer using Control Panel.
2. Computer print driver configured incorrectly.
a. Examine print driver setup to ensure printer driver setup doesn't override
desired features set via Control Panel.
3. Configuration card failure.
a. Verify configuration card is properly oriented and fully inserted.
b. Verify printer model purchased corresponds to features expected.
c. Clean configuration card contacts with isopropyl alcohol, reinstall, and
retest.
d. Swap configuration card with a known working card. If printer works,
replace card with one containing identical features as originally purchase.
e. The configuration card enables certain optional features in the printer. Care
must be taken to duplicate the features of the original printer when replacing
the card.

525-Sheet Feeder Does Not Function

1. Thermal safety fuse blown.
a. Power cycle printer.
b. The safety fuse is a self resetting device. Power cycling ensures the fuse
cools enough to reset itself.
2. 525-Sheet Feeder faulty.
a. Turn off printer and wait 30 seconds for power supply capacitors to
discharge.
b. Replace 525-Sheet Feeder.
c. Perform full test of printer.

Printer Is On (Electronics Module LEDs are Illuminated) but the Printer

Cannot Print Pages and the Control Panel Appears Frozen and No Error
Messages Are Displayed
1. Nonspecific electronics failure.
a. Double check PS and PE indicators for any error code information. The
printer self test is usually able to detect a failure that would cause this
symptom. Looking up the error code may save debugging time.
b. If the PS and PE indicators are steady and dimly-on, replace the electronics
module, reassembly and retest printer.
c. If the PS and PE indicators are blinking, brightly-on, or totally off, continue
debugging. A dim but steady on condition indicates some firmware was not
properly loaded into a logic circuit.

4-72 Phaser 8400/8500/8550 Color Printer

 d. With power cord connected, touch the metal electronics module to discharge
any static electricity.
e. Turn off printer and wait 30 seconds for power supply capacitors to
discharge.
f. Unplug power cord and remove printer's covers.
g. Unplug the following electronics module connectors:
■ Power Control to I/O board (J800)
■ Power Control right (J400)
■ Printhead data (J130)
■ Waveamp signal (J790)
■ Power Control left (J390)
■ Y-Axis motor (J280)
h. This step removes all other circuits so the electronics module can be tested
alone.
i. Plug in power cord and turn on power to the printer.
j. The PE and PS indicators should flash an error code reporting that the
Control Panel is missing. If the proper error message is not flashed, replace
the electronics module and retest the printer. If PE and PS indicators flash,
continue with debug.
k. Turn off printer and wait 30 seconds for power supply capacitors to
discharge
l. Unplug the following electronics module connectors:
■ Power Control to I/O board (J800)
■ Power Control right (J400)
■ Printhead data (J130)
■ Waveamp signal ('J790)
■ Power Control left (J390)
■ Y-Axis motor (J280)
This step prevents any faults from the motors, clutches and sensors from
preventing the I/O board and Control Panel from functioning.
m. Plug in the I/O board connector ('P' / J800) in the electronics module. This
step adds the I/O board and Control Panel to the electronics module.
n. Turn on power to the printer.
o. If the electronics module, I/O board and Control Panel are working, the error
code 34,001.43 should be displayed on the LCD to indicate the printhead is
disconnected.
p. If the correct error code is not displayed, replace the Control Panel and I/O
board and verify the correct error code appears on the LCD. Retest
electronics module, I/O board, Control Panel combination.
q. If the correct error code is displayed, continue with the next steps of the
procedure.

General Troubleshooting 4-73

 r. If no error code displays, return the original Control Panel and I/O board to
the printer. Replace the electronics module and then continue with the next
steps of the procedure.
s. If a different error code is displayed, see the "Fault Code Error Message
Troubleshooting" on page 3-9 for a definition of the problem and the
procedures needed to solve the problem.
2. Repeat the following procedures to check all circuits connected to the I/O board:
a. Turn off printer and wait 30 seconds for power supply capacitors to
discharge.
b. Plug in the following connectors, one at a time, and perform steps C and D
for each connector.
c. Turn on printer and wait for the error code 34,001.43. Check that the three
voltage indication LEDs INSIDE the electronics module (visible through the
vent holes of the electronics module near the AC power switch) are lit.
d. If the proper error code and LED doesn't appear after each I/O connector is
reconnected, repair or replace the faulty circuit.
e. If the proper code appears, repeat the procedures until all I/O board
connectors are plugged back in.
f. If repairs are made during this step, plug in all connectors to printer and
retest. If printer is fixed, reattach covers to printer and perform a full test. If
no defects are found in this step, continue with next step.
3. The proper error code is displayed, repeat the following procedures to check all
circuits connected to the electronics module:
a. Turn off printer and wait 30 seconds for power supply capacitors to
discharge.
b. Plug in the following connectors, one at a time, and perform steps C and D
for each connector.
c. Turn on printer and wait for the error code 34,001.43. Check that the three
voltage indication LEDs INSIDE the electronics module (visible through the
vent holes of the electronics module near the AC power switch) are lit.
d. If the proper error code and LED doesn't appear after each I/O connector is
reconnected, repair or replace the faulty circuit.
e. If the proper code appears, repeat the procedures until all I/O board
connectors are plugged back in.
f. If repairs are made during this step, plug in all connectors to printer and
retest. If printer is fixed, reattach covers to printer and perform a full test. If
no defects are found in this step, replace electronics module, test printer,
reattach covers to printer and perform a full test.

Verifying Print Engine Operation by Printing a Built-in Page.

1. If not already on, turn on the printer. If the printer does not begin initializing, go
to the topic, "Measuring AC Power Supply Voltages" on page 4-75.
2. Once the Power light is on (not blinking) and the Control Panel displays Ready
to Print it is now possible to print any built-in pages.
3. If the printer prints the Page, the print engine is working correctly. If the printer
does not print the Page, then a problem exists with the print engine.

4-74 Phaser 8400/8500/8550 Color Printer

Verifying Power Supply Operation
Required Tools
■ TORX T-20 screwdriver
■ Digital Multi-Meter (DMM)

The power supply is divided into two sections: the AC section used for heaters and the
DC section for control logic, printhead drivers, and motors. Verifying the power
supply involves three steps:
1. Checking for proper AC voltage.
2. Inspecting the power supply fuses.
3. Testing for a shorted motor or solenoid driver, which shuts down the power
supply.

+50 V Supply +3.3 V +15 High Side

Active LED Supply Active +12 Power
(Take 20 Seconds LED +5 Supply
to Drain Off) Active LED
s8500-031

Measuring AC Power Supply Voltages

1. AC line voltages are present on the power supply and possibly in the printer, via
the heaters, while the printer is plugged into an AC outlet. The power switch is
detected by software; a proper shut down follows a power off signal to the power
supply. The printer may operate for a considerable time after this procedure.
2. Turn off the printer, wait for shutdown, and unplug it from the power outlet.

General Troubleshooting 4-75

 3. AC Input: With a DMM set to measure AC voltages, measure the power being
supplied to the printer; it should measure between 90 to 140 VAC (115 VAC
nominal) or 180 to 264 VAC (220 VAC nominal).
4. Proceed to the step, “Testing Motor and Solenoid Resistances” below.
5. If a heater shorts, F2 or F3 opens. The power supply does NOT shut down;
however, a Service Required error code is displayed on the Control Panel.

Detecting condition of Fuse F2 and F3

1. The drum and preheater connect to F3.
2. The printhead and ink loader connect to F2.
3. Turn the power switch off and wait for the printer to shut down.
4. Unplug the power cord.
5. Remove the Ink Loader Assembly and Door as specified on page 8-8.
6. From the back of the printer you will see one heater cable connector on the left
near the power switch and two under the ink loader.
7. Place the power switch in the ON position and make the following
measurements:
a. Using an ohmmeter, measure the resistance between the lowest pin on the
left side, just above the power switch, and the lowest pin on the AC input
connector. If the meter measures 0 ohms, F3 has not been damaged.
b. Measure between the right most pin under the ink loader and (again) the
lowest pin on the AC input connector. If the meter measures 0 ohms, F2 has
not been damaged.
8. The heater triacs are not accessible for measurement and are disconnected from
loads if the switch is off or the printer is powered down.
9. Reinstall the Inkloader Assembly and Door following the test.

Measuring DC Power Supply Voltages

1. Check the power supply status LEDs, they should be bright.
2. If the printer is operational, use the diagnostic test Monitor Voltages.

Note
DC voltage test points can be found on the power control board. When you
remove the rear access cover, you will see the test points below the RAM
DIMM’s on the power control board.

4-76 Phaser 8400/8500/8550 Color Printer

Ensuring Ground Integrity
Intermittent or missing ground connections can result in minor interferences in the
printer. As examples:
■ Control Panel display can be affected (blank)
■ I/O board errors
■ False jam reporting
■ Erroneous thermistor readings
■ Major interruptions
■ Damage to the electrical boards

Key Ground Connections

The following illustration shows the grounding points in the printer.

I/O Board DM Ground X-Axis Motor

Transfix Roller Clip
Ground
Ground Springs

X-Axis Return
Spring Ground Y-Axis Motor Media Path Drive
Ground Ground
s8500-032

General Troubleshooting 4-77

Testing Motor and Solenoid Resistances
1. Turn off the printer and disconnect the power cord.
2. With a DMM set for measuring resistance, test each motor's windings for correct
resistance (disconnected from the printer). Rotate the motor's drive shaft slightly
while taking the measurement.

Motor and Solenoid Resistances

Motor or Solenoid Resistance (Approximate)

Process motor 4.3 ohms +/-15% (Difficult to measure due to variability at

the brush/commutator interface.)

Y-axis motor 1.4 ohms +/- 15% (Difficult to measure due to variability
at the brush/commutator interface.)

X-axis motor 12.5 ohms/phase (red-to-yellow and blue-to-orange)

Media path motor 1.5 +/- 20% ohms

Wiper drive clutch 186 ohms +/- 15%

Paper-pick clutch 186 ohms +/- 15%

Deskew clutch

MPT Pick solenoid 124 ohms +/- 5%

4-78 Phaser 8400/8500/8550 Color Printer

Paper Path and Media-Based Problems
For paper path and media-based problems, first check the displayed error codes using
the Error Code Definition Table beginning on page 3-9 to help determine where the
error is occurring. Run paper path diagnostics to help eliminate problems with printer
components.

Media-Based Problems
1. Check that the correct type of media is being used, for information on the correct
media type and sizes refer to the Paper Tips page, which is printable from the
printers Control Panel Menu.
2. Ensure the printer is operating under the right environmental conditions, see
Chapter One for more information.
3. Ensure the correct weight of paper is being used.
4. Ensure that envelopes are of an acceptable size and oriented with the flap up for
Tray 1 and the flap down for Trays 2, 3, and 4.
5. Ensure that the correct media is in the correct media tray. The paper guides
indicate to the printer the size of media being used. Ensure that the media guides
in the tray are set correctly.
6. Inspect the paper for bent, torn or folded corners.
7. Check to ensure no small pieces of paper are in the paper path.
8. Run the paper path status test in service diagnostics to ensure all sensors are
operating correctly.
9. Try printing from a fresh, unopened ream of paper.

Paper-Pick Errors - Trays 2, 3, and 4

Paper-pick errors occur when the media in the media tray mispicks or the printer
double-picks two or more sheets of paper.
1. Inspect the paper path for obstructions.
2. Ensure that the side guides are set correctly by sliding the guide gently against
the media.
3. Try printing from a fresh, unopened ream of paper.
4. Flip over the media in the tray.
5. Ensure the pick rollers for Trays 2, 3, and 4 are installed correctly.
6. Clean the pick roller using the cleaning procedures. Paper dust can coat the pick
roller and affect its ability to grip the paper and pull it out of the tray. Also clean
the transport rollers if they are visibly dirty. Refer to page 7-4 for proper cleaning
procedures.

General Troubleshooting 4-79

 7. Check that the pick roller is being rotated.
8. Run the Paper Path test.
9. Replace the pick roller if damaged.
10. Inspect the rollers, bushings and gears of the paper path.

Paper-Pick Errors - Tray 1

1. Verify the media being used is the correct size and weight.
2. Clean the Tray 1 pick roller and separator pad, refer to the cleaning procedure.
3. Ensure the printer is operating under the right environmental conditions, see
Chapter One for more information.
4. Run the Tray 1 Pick Solenoid test, replace if necessary.
5. When Tray 1 is opened or closed with media present the pick roller will home
and pick paper. Remove all media, open and close Tray 1 and then try printing
again.

Preheater and Transfix Jams

1. Remove the preheater and check for and remove any small paper scraps that may
be present.
2. Check for excessive media skews.
3. Check for ink shards on top of the preheater next to the flag (see page 8-23).
4. Using diagnostics, run the media drive path test. If the test fails, replace the
preheater assembly.
5. Check the paper-eject path for obstructions. Ensure no small pieces of paper are
trapped around the paper release blade.
6. Ensure that the transfix roller is rotating freely, replace if necessary.
7. Test the sensors in the paper path. Look for damaged or non-operating sensor
flags.
8. Check the stripper solenoid is functioning properly by running the stripper
solenoid test and the stripper contact test, replace if necessary.
9. Check the stripper blade for damage, replace the stripper carriage if necessary.
10. Check for ink shards on top of the preheater next to the flag (see page 8-23).

4-80 Phaser 8400/8500/8550 Color Printer

Checking the Process and Media Path Drive
1. Determine if the process motor runs. If it does not rotate, go to Step 2. If it does
rotate, go to Step 4.
2. Measure to determine if +50 VDC is being supplied to the motor. If power is
applied, go to Step 3. If it is not, inspect the process motor's wiring harness. If the
harness is functional, then troubleshoot the electronics module. Refer back to the
topic, "Measuring AC Power Supply Voltages" on page 4-75.
3. Disconnect the motor's wiring harness. Measure the resistance of the motor's
windings. If the windings are opened, shorted or far out of tolerance, replace the
motor.
4. Ensure the process drive gearbox is in it’s proper home position, refer to page
page 6-8.
5. Run the paper path drive test.
6. Run the drum maintenance drive test.
7. Run the transfix fast and transfix slow.
8. Run the process motor and media drive motor tests.
9. Inspect the gears and mating cam gears for stripped or damaged gear teeth.
10. Replace the Process Drive Gearbox.
11. Replace the media path drive gearbox.

Media Skews Passing Through the Paper Path

1. Ensure the media is supported.
2. Ensure that the side guides are properly adjusted.
3. Do not overfill the tray, especially with envelopes.
4. Check to see if the media is excessively curled. Curled media can get mistracked
in the paper path.
5. Examine the paper path; ensure it is clear of obstructions.
6. Ensure that the pick roller is not visibly dirty so that it picks up a sheet of media
smoothly and evenly.
7. Check and clean or replace, as required, the preheater and/or take away rollers.
Also make sure that the front door is properly closed.
8. The printer should be installed on a flat, level surface.
9. Ensure the paper preheater assembly is clean and properly seated into the printer
frame.

General Troubleshooting 4-81

Operating System and Application Problems
Print an internal test print from the printer’s Control Panel to ensure the problem is
not printer related. There is additional help available at www.xerox.com/office/
support. You can access the infoSMART Knowledge Base, PhaserSMART Technical
Support, Technical Support via email, driver downloads, and much more.

PhaserSMART Technical Support is an automated, Internet-based support system.

Use your default web browser to send diagnostic information from your printer to our
web site for analysis. PhaserSMART Technical Support examines the information,
diagnoses the problem, and proposes a solution.
To access PhaserSMART Technical Support:
1. Go to www.phaserSMART.com.
2. Enter your printer’s IP address in the browser address window.

Testing Communications Ports

Testing the communication ports can isolate communication problems to the
computer, network, or software. Test the communications ports after the printer is
installed or when the electronics module has been replaced. Test the communications
ports as follows:

Ethernet Port Verification

Note
The Ethernet port can be tested without connecting to the network by using a
crossover cable and the “PING” command.

1. Connect a crossover cable between the Ethernet ports on the printer and
computer.
2. Verify that the printer is Ready To Print.
3. At the computer, click the Start button, and select Run.
4. Type in the word “command” and click OK to launch the MS-DOS command
prompt.
5. At the prompt, type in the command “ipconfig” and press Enter to display the
computer’s IP address, subnet mask, and gateway.
6. On the Control Panel, print the Configuration Page and use this page to verify
that TCP/IP is enabled and to determine the current TCP/IP values.

Note
To enable communication between the computer and printer, both must be
configured for the same TCP/IP network.

4-82 Phaser 8400/8500/8550 Color Printer

 7. Using the printer Control Panel, disable DHCP/BOOTP and AutoIP so that the
printer can be configured manually.
8. Select an IP address for the printer that matches the computer, except for the last
field, which must be unique.
9. Edit the printer’s gateway and subnet mask to match the computer.
10. At the MS-DOS command prompt, type “ping” followed by a space and the
printer’s IP address. Then press Enter. If the number of packets sent and received
match, the PING was successful and the Ethernet port is functional. If the request
times out and fails to reply, either the cable or the port is defective.

Ethernet Port Verification for Default Assigned IP Address

169.254.xxx.xxx
An alternate method is required to test the Ethernet port when the PC’s IP address
falls within the range 169.254.xxx.xxx. PCs that have not been configured for a
specific network default to a “LOCAL LINK” value within the 169.254.xxx.xxx
range.

Note
To comply with industry standards, Phaser 8400 printers cannot be manually
configured for IP addresses within the LOCAL LINK range.

Note
Always print the Configuration Page to obtain a record of the printer settings
before changing the IP address. After testing the printer, be sure to restore the
printer’s original network settings.

1. Connect a crossover cable between the PC and printer.

2. Verify the printer is Ready To Print.
3. Use the printer’s Control Panel to enable AutoIP:
a. Select the Printer Setup menu.
b. Select the Connection Setup menu.
c. Select the Network Setup menu.
d. Select the TCP/IP Setup menu.
e. Set AutoIP to On.
f. Exit the menu so the printer is Ready To Print.
4. Reset the printer to cause AutoIP to assign a new IP address (cycle power or
select Restart Printer from the Shutdown menu).
5. After the printer’s IP address is set, test communication by sending the “PING”
command.
6. If the test fails, install a different cable and retest.

General Troubleshooting 4-83

USB Port Verification
1. Verify that the printer is Ready To Print.
2. Insert the Printer Installer and Utilities CD-ROM (8400) and Software and
Documentation CD-ROM (8500/8550) into the computer.
3. If the installer autoruns, exit the installer window.
4. Connect a USB cable between the printer and computer USB ports. The
computer automatically detects the new hardware and creates a driver.

Note
If the files from the driver are not currently installed on the computer, you
must locate the driver files on the CD-ROM. Once the files have been
located, the computer installs the driver and automatically configures it to
match the printer’s feature set.

5. To test the connection, click the START button.

6. Select SETTINGS and then PRINTERS.
7. Locate the Phaser 8400/8500/8550 Color Printer icon and display its properties.
8. From the General tab, click the Print Test Page button to generate the test print. If
the test page prints, the USB port is functioning normally.

Network Problems
The printer maintains 6 logs in memory detailing network functions. The logs contain
TCP/IP, NetWare and AppleTalk initialization events. The logs can also be accessed
remotely via CentreWare.
The logs list events chronologically. The log is limited in length; when the log is full
the printer stops recording data to the log. The logs are stored on the Hard Drive so
only new data is stored each time the printer’s power is cycled.
There is a Connection Setup Page, Configuration Page, and a network reset available
for troubleshooting Network problems.

To print an Event Log or Runtime Log:

1. Enter normal ‘Customer Mode’.
2. From the main menu, select Troubleshooting and press OK.
3. Scroll and select Network Log Pages and press OK.

4-84 Phaser 8400/8500/8550 Color Printer

 4. Highlight the appropriate menu item from the list and select OK.

Note
Phaser 8500/8550 printers use a diagnostic tool for network connections. It
is available using the menu path Troubleshooting>Network
Problems>Network >Diagnostics. To troubleshoot network problems,
you can select the standard Network Log Pages or the new Network
Diagnostics. The Network Diagnostics take about 60 seconds to test the
network connection for basic communication problems such as collisions,
wrong ethernet speeds, possible missing hubs when not using crossover
cable, and inappropriate IP settings for the network type detected or server.

5. The page should now print.

Note
To print the Connection Setup Page or Configuration Page, select the
Printer Setup Menu.

Obtaining Serial Back Channel Trace

In rare cases the printer may exit unusual behavior that is difficult to troubleshoot. In
such cases, if feasible, it can be useful to obtain a Back Channel Trace from the
printer’s on-board serial port. The Back Channel Trace, lists step-by-step what the
printer is doing up to the point that an error occurs. The trace may offer clues to help
troubleshoot the problem. You will need the following:

■ Computer with a serial port

■ Null modem serial cable

■ Serial cable adapter, part number 174-3493-00 (Same adapter used to run PC-
based diagnostic on Phaser 340/360 and Phaser 840 printers.)

To obtain a trace:
1. Connect the serial cable to your PC. Serial port settings are 19.2 kbaud, 8 bits, no
parity, 1 stop bit, and software control.
2. Turn off the printer.
3. Remove the rear panel to access the main board.
4. (8400 only) Connect the serial cable with adapter to the 5-pin connector (labeled
SER0) located above the RAM DIMM connectors. Pin 1 is the top pin. The label
THIS SIDE UP of the serial port adapter should face towards the main board’s
round back-up battery.

(8500/8550 only) Connect the serial cable with adapter to the service only port
located above the USB cable port. The label THIS SIDE UP on the serial adapter
should face the rear of the printer.

General Troubleshooting 4-85

 5. Start up a terminal program, such as in window’s HyperTerminal (usually located
in Programs:Accessories:Communications:HyperTerminal). Ensure the serial
port settings, usually COM1: is correct.
6. Turn on the printer.
The trace should appear in the terminal dialog window. Examine the trace to
troubleshoot the problem. If necessary, save the trace file to capture the text.

4-86 Phaser 8400/8500/8550 Color Printer

Print-Quality
Troubleshooting
In this chapter...
■ Print-Quality Problems Overview
■ Analyzing Service Test Prints

Section
5
Print-Quality Problems Overview
Print-quality defects can be attributed to printer components, consumables, media,
internal software, external software applications, and environmental conditions. To
successfully troubleshoot print-quality problems, as many variables as possible must
be eliminated. The first step is to generate prints using printable pages embedded in
the printer on paper from the approved media list. The paper should be from an
unopened ream that has been acclimated to room temperature.
See the approved media list from, "Xerox Supplies" on page 9-16 for media that has
been tested and approved for use in this printer. If the print-quality defect is still
present when printing on approved media from an unopened ream of paper, then
media, software applications, and environmental conditions need to be researched.
When analyzing a print-quality defect, first determine if the defect occurs:

■ in all colors

■ in only one color

■ if it is repeating or random

The visible surfaces of all rollers should be inspected for obvious defects.

Diagnosing Print-Quality Problems

The Troubleshooting Print-Quality Page provides a good overview of the most
common print quality problems. To print the Troubleshooting Print-Quality Page,
follow these steps:
1. From the Control Panel, scroll to Troubleshooting, then press OK.
2. Scroll to Print Quality Problems, then press OK.
3. Scroll to Troubleshooting Print Quality Page, then press OK.
The Troubleshooting Print Quality Page includes instructions for printing the
Eliminate Light Stripes test print. These instructions are also provided on the next
page of this manual. The Eliminate Light Stripes test print indicates individual weak
or missing jets or an obstruction in the imaging path that affects a vertical band down
the entire page. Also, you may see color variation from jet to jet on the Eliminate
Light Stripes test print. Some variation is normal, occasionally occurs, and usually
self-corrects within a few printed pages. If a print-quality problem is not resolved
with the information provided in the Diagnosing Print-Quality Problems section, see
the specific problem in "Analyzing Service Test Prints" on page 5-33.

5-2 Phaser 8400/8500/8550 Color Printer

Random Light Stripes
One or more color bars are missing on
Light Stripes Test
the test page.
This is probably caused by a weak or
clogged printhead jet.

Step Questions and Actions Yes No

1 1. On the Control Panel, select the Eliminate Complete. Go to Step 3.

Light Stripes function and follow the
procedure on the printed pages. For Phaser
8400 printers, this step does not include Jet
Substitution.
2. Did this correct the problem?

2 1. It may be necessary to repeat Step 1

up to 3 times if the stripes still appear.
NOTE: If there are discolored jets, print the
solid fill test print in the color with the
discolored jets. In the following
example, the yellow stripe has
discolored jets, therefore you would
print the yellow solid fill. For
instructions on printing solid fill test
prints, see "Black, Red, Green, Blue,
Cyan, Magenta, and Yellow Solid
Fills" on page 5-40.
Discolored jets usually clear after two or
three prints, using the problem jets.

3 1. Clean the print engine exit path and wipe the Complete. Go to Step 4.
paper release blade with a lint-free cloth.
2. Did this correct the problem?

4 1. Remove the drum maintenance kit and wipe Complete. Go to Step 5.

the clear plastic wiper blade with a lint-free
cloth or replace the maintenance kit.
2. Did this correct the problem?

Print-Quality Troubleshooting 5-3

Step Questions and Actions Yes No

5 1. (8400) Download the latest Jet Fix snippet Complete. Go to Step 6.

from the Customer Support Site and follow the
readme text instructions. You will:

Select “Advanced”. You will be prompted to

choose the color and number of the problem
jet based on the Light Stripes Test page. After
selections are made, the printer temporarily
increases the drive voltage to the selected jet,
prints several pages, and then performs the
cleaning sequence.

The Advanced cleaning process is similar to

the process associated with downloading the
“Jet Fix” snippet to Phaser 8400 printers.
However, a snippet is not required for Phaser
8500/8550 printers because the feature is
embedded in the printer’s firmware.
For Phaser 8500/8550, if the problem
persists, select the Jet Substitution Mode:
2. On the Control Panel, select
Troubleshooting, and then press the OK
button.
3. Select Print Quality Problems, and then
press the OK button.
4. Select Eliminate Light Stripes, and then
press the OK button.
5. Select Jet Substitution Mode, and then press
the OK button.
6. Follow the Control Panel prompts to select the
color and malfunctioning jet number indicated
on the Light Stripes Test page.
7. Did this correct the problem?

6 1. Turn off the printer for at least 4 hours. Complete. Follow the
2. Turn on the printer and if necessary, repeat instructions on
Step 1. the “Printhead
3. Did this correct the problem? Troubleshooting
Checklist”.

5-4 Phaser 8400/8500/8550 Color Printer

Predominate Light Stripes
All four color bars are missing on the
test page. A thin stripe with no colon
is likely due to foreign debris
scratching ink off the drum or the
print.

Note
If there are a series of regularly
spaced white lines
approximately 6 mm (.25 in.)
apart see “White Stripes
(Pinstripes)” on page 30.

Step Questions and Actions Yes No

1 1. Clean the printer’s exit path, including wiping Complete. Go to Step 2.

the paper release blade with a lint-free cloth.
2. Did this correct the problem?

2 1. Remove the drum maintenance kit and wipe Complete. If the problem
the clear plastic wiper blade with a lint-free persists, follow
cloth. the steps for
2. Did this correct the problem? "Random Light
Stripes" on
page 5-3.

Print-Quality Troubleshooting 5-5

Smudges or Smears
Smudges or smears appear on the page.
The probable cause is ink residue in the paper path. The
residue can be found on the roller, on the paper guide ribs, or
inside the paper preheater.
NOTE: To avoid future problems, if you are manually printing on duplex
paper with preprinted solid ink images, you should select "2nd Side" as
the paper type after cleaning the paper path.

Step Questions and Actions Yes No

1 1. Clean the printer’s exit path, including wiping Complete. Go to Step 2.

the paper release blade with a lint-free cloth.
2. Did this correct the problem?

2 1. On the Control Panel, select Information --> Complete.

Troubleshooting --> Print Quality Go to Step 3.
Problems.
2. Select Remove Print Smears, and then
press the Enter button. The printer cleans
the ink from the preheater and exit rollers.
3. Reprint test pages. Do you still see
smudges?

3 1. Repeat Step 2 up to 3 times if the smears Complete. Go to Step 4.

still appear.
2. Verify supported media is being used.
3. Open a fresh ream of supported paper and
reprint the test page.
4. Did this correct the problem?

4 1. Remove the drum maintenance kit and wipe Complete. Go to Step 5.

the clear plastic wiper blade with a lint-free
cloth.
2. Did this correct the problem?

5 1. Manually clean visibly dirty feed rollers. Complete. Go to Step 6.

2. Clean the paper release blade.
3. Did this correct the problem?

6 1. Verify the maintenance pivot plate is free Complete. Replace the

from damage. preheater.
2. Verify the cam rollers for the drum
maintenance are working properly.
3. Replace any defective parts.
4. Did this correct the problem?

5-6 Phaser 8400/8500/8550 Color Printer

Printing Too Light or Too Dark
Step Questions and Actions Yes No

1 1. Verify the paper type at the Control Panel Complete. Go to Step 2.

matches the paper type in the driver and in
the software application being used,
especially if printing on transparency.
2. Verify the paper type is a supported media
type for this printer.
3. Did this correct the problem?

2 1. Change/adjust the print mode settings or the Complete. Go to Step 3.

TekColor setting.
2. Did this correct the problem?

3 1. The ink may be discolored due to age or lack Complete. Go to Step 4.

of use over an extended period of time.
2. Insert new ink and print a solid fill test print.
Run the test print until the affected color
returns to normal.
3. Did this correct the problem?

4 1. If the problem is occurring for only one color, Complete.

purge the ink up to 10 times to clear the ink
or until discoloration is cleared.
2. Did this correct the problem?

Not Printing
The printer processes a sheet of paper, but no image is printed on it.

Note
Blank sheets accompanying multi-picks or chase pages following a jam are a part
of normal operation.

Step Questions and Actions Yes No

1 1. Inspect the area around the printhead and Complete. Go to Step 2

drum and remove any media or bits of paper
jammed between the printhead and drum.
2. Did this correct the problem?

2 1. Follow the instructions on the “Printhead Complete. Go to Step 3.

Troubleshooting Checklist”.
2. Did this correct the problem?

Print-Quality Troubleshooting 5-7

Step Questions and Actions Yes No

3 1. Inspect and reseat the wave amp and data Complete. Replace in the
cables connecting to the printhead. following order:
2. Replace or repair any defective cables. ■ electronics
module
3. Did this correct the problem?
■ printhead

5-8 Phaser 8400/8500/8550 Color Printer

Color is Uneven or Color is Wrong
This may be due to incorrect colors in the
ink loader, old ink in the printhead, color
mixing at the faceplate, or drum thermal
problems.

Note
Using non-Xerox ink may cause
unpredictable color results.

s8500-034

Step Questions and Actions Yes No

1 1. To remove discolored jets in the printhead, Complete. Go to Step 2

run the solid fill test print for the color
displaying the discolored jets.
NOTE: For instructions on printing solid fill test
prints, see "Black, Red, Green, Blue,
Cyan, Magenta, and Yellow Solid Fills" on
page 5-40.
1. Purge the printhead up to three times. If
some improvement is seen, the ink could be
discolored due to a long period of time
without use.
2. Did this correct the problem?

2 1. Clean the maintenance kit wiper blade or Complete. Go to Step 3.

replace the maintenance kit.
2. Did this correct the problem?

3 1. Check the thermal regulation of the drum. Go to Step 4. Go to Step 5.

2. Run the service diagnostics drum thermal
check test, see "Temperature Status" on
page 4-54.
3. Are the drum thermal values out of the
appropriate range?

Print-Quality Troubleshooting 5-9

Step Questions and Actions Yes No

4 1. Ensure the drum fan is correctly installed Go to Step 5. Replace the

and operates correctly. drum fan.

5 1. Verify the drum temperature sensor is in Complete. Replace in the

contact with the drum. following order:
2. Clean or replace the drum temperature ■ Drum heater
sensor. relay board
■ Drum
3. Did this correct the problem?
assembly
■ Electronics
module

5-10 Phaser 8400/8500/8550 Color Printer

Streaks or Lines Down the Print
There are several possible causes of
streaks running down the length of a
print.

s8500-035

Step Questions and Actions Yes No

1 1. Check for and remove any media, jammed Complete. Go to Step 2.

paper, or debris found in the printers exit
path.
2. Did this correct the problem?

2 1. Clean the maintenance kit wiper blade or Complete. Go to Step 3.

replace the maintenance kit.
2. Did this correct the problem?

3 1. Check the exit area, exit frame, the Complete. Go to Step 4.

preheater, maintenance kit, and the
printhead (including the paper release blade)
to see if there is anything touching the drum
assembly.
2. Reseat any printer component interfering or
touching the drum assembly.
3. Clean the paper release blade.
4. Did this correct the problem?

Print-Quality Troubleshooting 5-11

Step Questions and Actions Yes No

4 1. If there are streaks on the front side only of a Complete. Go to Step 5.

2-sided print, the preheater may be scraping
ink off the print.
2. Look for ink shavings along the streaks on
the printed paper.
3. Clean the preheater using the Control Panel
Remove Print Smears function.
4. Did this correct the problem?

5 1. Possible weak or missing jet. Print the weak/ Complete. Go to Step 6.

missing jet test print from the Control Panel,
see "Weak/Missing Jet" on page 5-33.
2. Did this correct the problem?

6 1. Possible discolored jet. Print the solid fill test Complete. Go to Step 7.
print, see "Black, Red, Green, Blue, Cyan,
Magenta, and Yellow Solid Fills" on
page 5-40.
2. Did this correct the problem?

7 1. The X-axis drive is not functioning correctly. Complete. Go to Step 8.

If the X-Axis Drive does not move the
printhead smoothly and evenly during
printing, vertical lines appear on the print.

For information about X-Axis Drive

problems, see "White Stripes (Pinstripes)"
on page 5-30.
2. Did this correct the problem?

8 1. Smears on a duplex print can be caused by Replace the Replace the

the paper preheater operating at a preheater. electronics
temperature that is too high or debris is in module.
the duplex roller or duplex paper path
guides.
2. Run the service diagnostics Duplex Path
test to check the paper preheater’s
temperature.
3. Is the operating temperature within the
correct value range?

5-12 Phaser 8400/8500/8550 Color Printer

Scratches or Marks Parallel to the Long Axis of Printing,
Particularly with Film
Usually caused by debris in the paper
path. The scratch or mark may extend
into non-printed areas or be more
pronounced on the lower portion of the
image.

s8500-036

Step Questions and Actions Yes No

1 1. Check the exit area, the preheater, Complete. Go to Step 2.

maintenance kit, and the printhead
(including the paper release blade) to see if
there is anything touching the drum
assembly.
2. Reseat any printer component interfering or
touching the drum assembly.
3. Clean the paper release blade.
4. Did this correct the problem?

2 1. Inspect the drum maintenance kit. If the Complete. Go to Step 3.

defect is a thin line that is glossier than the
surrounding area, it may be due to a defect
on the maintenance kit wiper blade.
2. Clean the wiper blade or replace the
maintenance kit.
3. Did this correct the problem?

Print-Quality Troubleshooting 5-13

Step Questions and Actions Yes No

3 1. Using transparency media, print from Tray 1 Go to Step 5. Go to Step 4.

to see if the scratch appears.
2. Is there a visible scratch?
NOTE: To determine where the scratch is
originating, place a small drop of water on
the scratch on the transparency. If the
scratch disappears, the scratch is on that
side.
If the scratch does not disappear, follow
these steps on the other side. This can
help to determine where the problem is
originating.

4 1. If there is no visible scratch on the Complete. Go to Step 5.

transparency the defect occurred during
paper pick or early transport from Tray 2, 3,
or 4.
2. Change the paper pick guide, front door, or
maintenance kit.
3. Did this correct the problem?

5 A scratch or smear can be caused by debris Complete. Go to Step 6.

build-up on the paper preheater’s heating
surface. Try the following:
1. Run the cleaning procedure Remove Print
Smears from the printer’s Control Panel.
2. Did this correct the problem?

6 1. Force a sheet of thick 65- to 80-lb. paper Complete. Go to Step 7.

through the paper preheater to “buff” the
paper preheater heating surfaces.
2. With the leading and trailing ends of the
sheet of paper extending from the entry and
exit of the paper preheater, gently pull the
sheet of paper back and forth several times
and then remove the paper. Be careful of the
paper-sensor flags.
3. Did this correct the problem?

7 1. Inspect all paper guides inside the printer for Clean or replace any defective
nicks, cuts, or debris. paper guide(s).

5-14 Phaser 8400/8500/8550 Color Printer

White Portion of Print is Colored
Color on a print where no color should
be printed is often called a latent image.
A latent image remains on the drum
when it should have been transferred to
its sheet of paper. An insufficient amount
of oil on the drum, provided by a dirty,
defective, or old maintenance kit may be
the problem.
Printing on 3-hole punch paper
commonly causes this problem.

s8500-037

Step Questions and Actions Yes No

1 1. Try printing using a smoother, higher quality Complete. Go to Step 2.

paper, some recycled paper brands may be
too rough. Watermarked or 3-hole punched
paper may also have this problem.
2. Did this correct the problem?

2 1. Inspect and clean the maintenance kit wiper Complete. Go to Step 3.

blade.
2. If necessary replace the maintenance kit.
3. Did this correct the problem?

3 1. Clean the paper release blade, it may be Complete. Go to Step 4.

contaminated with ink.
2. Run the Remove Print Smears from the
printer’s Control Panel.
3. Did this correct the problem?

4 1. Inspect for ink on the transfix roller. Complete Go to Step 5.

2. Run the Remove Print Smears from the
printer Control Panel.
3. Did this correct the problem?

Print-Quality Troubleshooting 5-15

Step Questions and Actions Yes No

5 1. Run service diagnostics to verify the system Complete. Go to Step 6.

temperatures are within normal operating
range.
2. Inspect the drum thermistor, clean or replace
if necessary.
3. Did this correct the problem?

6 1. Inspect the feed rollers. An accumulation of Complete.

paper dust and oil can produce dark
rectangular marks on transparency film.
2. Run the Remove Print Smears from the
printer’s Control Panel.
3. Replace the rollers if necessary.
4. Did this correct the problem?

5-16 Phaser 8400/8500/8550 Color Printer

Fuzzy Text
Text appears indistinct and difficult to
read.
There are three typical reasons for
fuzzy text, as called out in this
illustration.
1.Top left image displays a Y-axis
drum rotation problem.
2.Lower left image displays the wrong
drum temperature problem.
3.Lower right image displays an X-
axis movement problem.

32424-081

Step Questions and Actions Yes No

1 1. Try printing using a smoother, higher quality Complete. Go to Step 2.

paper, some recycled paper brands may be
too rough. Watermarked paper may also
have this problem.
2. Did this correct the problem?

2 1. Try using a higher quality print mode. Complete. Go to Step 3.

2. Did this correct the problem?

3 1. This problem can occur after a printhead has Complete. Go to Step 4.

been replaced. Verify the dot on the
printhead roll block is positioned to match
the label on the left frame. Adjust if
necessary.
2. Did this correct the problem?

4 1. Run service diagnostics to check the Complete. Go to Step 5.

temperature of the drum.
2. Verify the drum termperature sensor is clean
and properly positioned.
3. Did this correct the problem?

5 1. Use service diagnostics to run the Y-axis Go to Step 6. Clean the drum
encoder test. encoder disk or
2. Is the Y-axis encoder working properly? replace the
drum assembly.

Print-Quality Troubleshooting 5-17

Step Questions and Actions Yes No

6 1. Ensure the x-axis movement is not impeded. Complete. Go to Step 7.

2. See "White Stripes (Pinstripes)" on
page 5-30 for troubleshooting this problem.
3. Did this correct the problem?

7 1. Verify the printhead is tilted forward against Complete.

the drum in the proper print position.
2. Did this correct the problem?

5-18 Phaser 8400/8500/8550 Color Printer

Poor Primary Color Fills
Primary fills appear banded and
inconsistent.

s8500-039

Step Questions and Actions Yes No

1 1. Banded and inconsistent primary fills may Complete. Go to Step 2.

indicate a missing, weak, or discolored jet.
2. Print the Service Test Print 1: Weak/Missing
Jet.
3. If there are discolored jets, print the solid fill
test print in the color with the discolored jets.
4. Did this correct the problem?

2 1. Use service diagnostics to verify the Y-axis Go to Step 3. Clean the drum
encoder is operating normally. encoder disk or
2. Is the Y-axis encoder working properly? replace the
drum assembly.

3 1. If the bands are uniform, or in a corduroy Go to Step 4. Replace the X-

pattern, use diagnostics to check the X-axis axis motor or
motion. electronics
2. Ensure the x-axis movement is not impeded. module.
3. See "White Stripes (Pinstripes)" on
page 5-30 for troubleshooting this problem.
4. Did this correct the problem?

4 1. Try the procedure listed on "Black, Red, Complete.

Green, Blue, Cyan, Magenta, and Yellow
Solid Fills" on page 5-40.
2. Did this correct the problem?

Print-Quality Troubleshooting 5-19

Ghosting
The image from a previous print is on the
current print.

s8500-040

Step Questions and Actions Yes No

1 1. This problem can occur from prints being Complete. Go to Step 2.

stacked in the output tray, causing the
pressure of the stack and the heat of the
printer to cause “blocking” which has the
appearance of ghosting.
2. Try printing the images again, without letting
them stack in the output tray.
3. Try different paper. Ink may have a problem
adhering to smooth, impervious surfaces of
some paper.
4. Did this correct the problem?

2 1. Run multiple prints; the first 2-sided print will Complete. Go to Step 3.
have the worst ghosting. Some transfix roller
ghosting is inherent to the printer but will
improve with multiple prints.
2. Does this correct the problem?

3 1. Inspect and clean the maintenance kit wiper Complete. Go to Step 4.

blade.
2. If necessary, replace the maintenance kit.
3. Did this correct the problem?

5-20 Phaser 8400/8500/8550 Color Printer

Step Questions and Actions Yes No

4 1. Run service diagnostics to verify the drum Complete. Go to Step 5.

maintenance system is operating correctly.
2. Inspect or replace the following parts, check
for cracking:
■ Drum maintenance pivot plate
■ Drum maintenance cam shaft
3. Did this correct the problem?

5 1. Run service diagnostics to check the Complete. Replace the

temperature of the drum. drum
2. Verify the drum termperature sensor is clean temperature
and properly installed. sensor.
3. Did this correct the problem?

Print-Quality Troubleshooting 5-21

Poor Small Text Resolution
Small characters appear heavy and
“plug up.”

s8500-038

Step Questions and Actions Yes No

1 1. Try using a higher quality print mode. Complete. Go to Step 2.

2. Did this correct the problem?

2 1. Run service diagnostics to check the Complete. Go to Step 3.

temperature of the drum.
2. Verify the drum temperature sensor is clean
and properly positioned.
3. Did this correct the problem?

3 1. Verify the X-axis drive system is correctly Complete. Replace the

assembled and lubricated, see "X-Axis x-axis motor
Motor Assembly" on page 8-53 for more assembly.
information.
2. Did this correct the problem?

5-22 Phaser 8400/8500/8550 Color Printer

Vertical Lines Appear Wavy
Straight vertical lines appear to be wavy
and ill-formed.

s8500-041

Step Questions and Actions Yes No

1 1. There may be too much oil on the drum. Complete. Go to Step 2.

2. Inspect and clean the maintenance kit wiper
blade.
3. If necessary, replace the maintenance kit.
4. Did this correct the problem?

2 1. Check the motion of the X-axis and verify Complete. Go to Step 3.

there is nothing interfering such as a poorly
dressed cable or screw.
2. Replace any defective parts.
3. Did this correct the problem?

3 1. Use service diagnostics to run the Y-axis Go to Step 4. Clean the drum
encoder test. encoder disk or
2. Is the Y-axis encoder functioning properly? replace the
drum assembly.

4 1. Use service diagnostics to verify the drum Complete. Replace the

maintenance cam roller and pivot plate are pivot plate or
operating correctly. drum
2. Did this correct the problem? maintenance
cam roller if
damaged.

Print-Quality Troubleshooting 5-23

Oil Streaks on Print
Oil stains the edge of the print.

s8500-042

Step Questions and Actions Yes No

1 1. There may be too much oil on the drum. Complete. Go to Step 2.

2. Inspect and clean the maintenance kit wiper
blade.
3. If necessary, replace the maintenance kit.
4. Did this correct the problem?

2 1. Ensure ground integrity for the drum Complete. Go to Step 3.

maintenance unit is intact.
2. Check the back of the drum maintenance
unit to drum maintenance shaft to drum fan
ground clip.
3. Did this correct the problem?

3 1. Run pages through the printer to clean the Complete. Go to Step 4.

drum by using the Remove Print Smears
routine from the printer’s Control Panel.
2. Did this correct the problem?

4 1. Clean the paper release blade and the exit Complete. Go to Step 5.
guides.
2. Did this correct the problem?

5-24 Phaser 8400/8500/8550 Color Printer

Step Questions and Actions Yes No

5 1. Use service diagnostics to verify the drum Complete. Replace the

maintenance cam roller and pivot plate are pivot plate or
operating correctly. drum
2. Did this correct the problem? maintenance
cam roller if
damaged.

Print-Quality Troubleshooting 5-25

Incomplete Image Transfer to Paper
All of the image does not transfer to the paper.
Media that is not smooth enough or too light
can cause this problem. This problem can also
occur on watermarked paper.

s8500-043

Step Questions and Actions Yes No

1 1. Verify the media is supported for this printer Complete. Go to Step 2.

and/or try a higher quality or heavier media
type.
2. Did this correct the problem?

2 1. Try using a higher quality print mode. Complete. Go to Step 3.

2. Did this correct the problem?

3 1. Poor drum oiling can cause the image

transfer to be incomplete on one side of the
page.

4 1. Use service diagnostics to verify the drum Complete. Go to Step 5.

maintenance cam roller and pivot plate are
operating correctly. Replace any defective
parts. Inspect for cracked pivot plate or
cracked drum maintenance cams.
2. Did this correct the problem?

5 1. Inspect and clean the maintenance kit wiper Complete. Go to Step 6.

blade.
2. If necessary, replace the maintenance kit.
3. Did this correct the problem?

5-26 Phaser 8400/8500/8550 Color Printer

Step Questions and Actions Yes No

6 1. Inspect the drum temperature sensor and Complete. Go to Step 7.

check for contamination and improper
positioning between the sensor and the
drum surface.
2. Clean and position the sensor as necessary
3. Did this correct the problem?

7 1. Is the incomplete image transfer on the left Complete. Go to Step 8.

and right sides of the print, but fine through
the center?
2. This indicates incomplete transfix cam
rotation. Check for a damaged transfix cam
roller or a malfunction of the process drive,
replace any defective parts.
3. Did this correct the problem?

8 1. Using service diagnostics, verify the paper Complete. Replace the

preheater temperature is within normal transfix load
operating range. assembly and
2. Replace the paper preheater if necessary. transfix load
arm.

Print-Quality Troubleshooting 5-27

Ink Smears on First Printed Side of Duplex Print
Preheater temperature is too high.

s8500-044

Step Questions and Actions Yes No

1 1. Clean or replace the paper release blade. Complete. Go to Step 2.

2. Did this correct the problem?

2 1. Inspect the duplex paper path for Complete. Go to Step 3.

obstructions, contamination, debris, or
damage.
2. Clean or replace defective parts.
3. Did this correct the problem?

3 1. Run the Remove Print Smears routine from Complete. Go to Step 4.

the printer’s Control Panel.
2. Did this correct the problem?

4 1. Use service diagnostics to check the paper Replace in the following order:
preheater temperature. ■ preheater
2. Is the preheater operating within normal ■ electronics module
range?

5-28 Phaser 8400/8500/8550 Color Printer

Repeating Print Defects on Print
The distance between each artifact of
a repeating image defect reveals
which imaging component is causing
the defect. Transfix Roller defects
show up as light spots in solid fill
areas.

s8500-045

Step Questions and Actions Yes No

1 1. Repeating defects that occur every 11.6 cm Complete. Go to Step 2.

(4.58 in.) are caused by the transfix roller.
2. Clean the transfix roller. The defect does not
move in the X-position.
3. Replace if necessary.
4. Did this correct the problem?

2 1. A single repeating defect that has a different Complete. Replace the

Y position on each page, but the same X drum assembly.
position on each page is probably due to a
defect on the drum.
2. Clean the drum assembly.
3. Did this correct the problem?

Print-Quality Troubleshooting 5-29

White Stripes (Pinstripes)
This print-quality problem has a series
of regularly spaced white stripes
approximately 6 mm (.25 in.) apart. If
the X-Axis Drive does not move the
printhead smoothly and evenly during
printing, vertical lines appear in the
print.

s8500-046

Step Questions and Actions Yes No

1 1. Print the service test print 13-19 Solid Fills, Go to Step 2. Complete. The
to reveal an X-axis problem. See "Primary problem is not
Solid Fills 10x" on page 5-41 for more with the print
information. engine.
2. Are the pinstripes apparent on the test
prints?

2 1. Verify the X-axis motion is operating Complete. Go to Step 3.

correctly and that poorly dressed cables,
loose screws, or mechanical failures are not
interfering.
2. Remove any obstructions or redress cables.
3. Did this correct the problem?

3 1. Verify there are no wiring harnesses Complete. Replace the

interfering with the horizontal movement of X-axis drive.
the printhead.
2. Redress any faulty wiring.
3. Repair or replace any defective part or
interference with the printhead.
4. Did this correct the problem?

5-30 Phaser 8400/8500/8550 Color Printer

Wrinkling
The print is usually damaged in a corner
with solid fills. This problem is more
often seen on short-grain media. Some
wrinkling on envelopes flaps is an
acceptable limitation of this printer. You
may see wrinkling on the second side of
a 2-sided print on the secondary colors.
Wrinkling can also be caused if the pre-
heater is too open on the duplex side of
the print.
On the paper’s packaging, an underline
under the 11 (in 8.5in. x 11in.) indicates
the paper is long-grain.

s8500-047

Step Questions and Actions Yes No

1 1. Verify the media is supported for this printer. Complete. Go to Step 2.

2. Print from an unopened fresh ream of paper.
3. Try a higher quality or heavier media type.
4. Did this correct the problem?

2 1. Increase the margin size of the image. Complete. Go to Step 3.

Wrinkling generally occurs in solid fills near
the print’s edge.
2. Did this correct the problem?

3 1. Did the print “wrinkle” on the duplex side Replace the Go to step 4.
only? paper-preheater

4 1. Inspect, clean or replace the maintenance Complete. Go to Step 5.

kit.
2. Did this correct the problem?

5 1. Inspect the transfix components. Replace in the following order:

■ transfix roller
■ transfix cam
■ transfix load arm
■ transfix load module.

Print-Quality Troubleshooting 5-31

Image Is Offset or Cut-Off
1. Print an information page (internal page embedded in the printer).
2. Verify that the tray guides are adjusted correctly.
3. Ensure that the paper size in the driver and printer match the paper loaded in the
tray.
4. Check the application for the correct image sizing and orientation.

Poor Ink Adhesion, Poor Image Durability

Follow these steps if the ink is flaking off the print after the print is complete.
1. If a specialty coated paper is being used (for example, glossy media), try a
different paper. Xerox transparency film provides the best ink adhesion versus
off-the-shelf transparency film.
2. Verify the paper preheater temperature using diagnostics.
3. The drum is too cold or too hot. Verify the drum temperature using diagnostics.
Ensure that the drum temperature sensor is properly positioned and has no
contamination between it and the drum surface.
Image durability is almost always an issue with the paper being used. It is never an
issue with the printer’s printhead.

5-32 Phaser 8400/8500/8550 Color Printer

Analyzing Service Test Prints
A variety of test prints are available in the Hidden Service Menu to aid in determining
the quality of output from the printer and to assist in troubleshooting problems. This
section shows how to select and analyze all test prints available to the Phaser 8400
printer. To access the Service Tools menu: From anywhere within the menu (not
diagnostics), press and hold the Up Arrow button, and then press the OK button. You
can also press and hold the Cancel button, and then press the OK button. To enter the
Hidden Service Menu: from the Service Tools menu, press and hold the Up Arrow
and Down Arrow buttons.

Note
Defects revealed by the prints may not occur in the course of ordinary printing. In
servicing the printer, you should minimize the defects shown by the prints but not
necessarily eliminate them.

Test Print Examples

Weak/Missing Jet
This print shows which jets are not outputting
enough, if any, ink compared to its neighboring
jets. Note that the yellow jets’ bands have a
small amount of cyan ink added to them, which
tints them green, to make them more visible.

Look for: No interlacing is used in this print;

expect light/dark variation between jets. Look
for much lighter colored vertical bands in the 74 75 76 77 78 79 80

Weak jet
horizontal bars. Weak jets in the yellow band
are distinguished by a cyan tint.

Causes: A jet may be partially clogged;

perform printhead clean/purge cycles on the
printhead to remove contaminants from the
poorly-performing jet. If jet substitution mode is
required, see "Jet Substitution Mode" on
page 6-10. Test the purge system and the wiper
blade performance. Turn the printer off for 4 to 6
hours (or overnight, if practical). Then perform a s8500-048
clean/purge cycle again. There may be a
problem in the purge pump assembly or the
wiper assembly may not be compliant. Verify
that Xerox ink is being used. Follow the
instructions on the “Printhead Troubleshooting
Checklist”.

NOTE: Include two prints of this test print with

any returned printhead.

Print-Quality Troubleshooting 5-33

Test Print Examples (Continued)
X-Axis Motion (Drop Mass
Evaluation)
(8400 only)
For X-Axis Motion problems, see "Analyzing
This is a text print

Service Test Prints" on page 5-33 (solid fill This is a text print
This is a text print
This is a text print
This is a text print
This is a text print

prints). This is a text print

This is a text print
This is a text print
This is a text print

This print is used by Engineering and

This is a text print
This is a text print

This is a text print

Manufacturing. The print must be printed on This is a text print

This is a text print
This is a text print
This is a text print
This is a text print

Xerox Photo Paper. Using a lower grade paper This is a text print
This is a text print
This is a text print
< current setpoint
This is a text print

will result in inaccurate measurements. This is a text print

This is a text print

This is a text print

This is a text print
This is a text print
This is a text print
This is a text print
This is a text print

This is a text print

This is a text print
This is a text print
This is a text print
This is a text print
This is a text print

This is a text print

This is a text print
This is a text print
This is a text print
This is a text print
This is a text print

s8500-049

Color Bands, RGBK Dither

The large, secondary colored areas in this print
reveal banding and weak jets.
Look for: Vertical “bars” or bands of much
lighter color or a different hue running in-line in
one or more of the solid fills.
Causes: A weak jet can cause banding; see
the Weak/Missing Jets test print (on Banding
page 5-33). Banding can also be caused by
color-to-color misregistration. Use the
diagnostics to ensure that the printhead and
drum thermals are correct. Follow the
instructions on the "On-site Printhead
Troubleshooting Checklist (8400)" on page A-8

s8500-050

5-34 Phaser 8400/8500/8550 Color Printer

Test Print Examples (Continued)
Reverse Text
10 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890

The print indicates if the printhead is producing 8 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

6 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

properly-sized drops of ink and that the drum 5 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*
4 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

temperature is not too high. 10 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890

8 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

NOTE: This print should be made with the 6 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*
5 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*
4 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

printer covers closed and in place. The

heat loss without the covers can hide the 10 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890
8 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&* 1234567890
“too-hot” thermal problem. Also, print the 6 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*
5 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

test print in Enhanced print mode. 4 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

Look for: Legibility in the lines of 6-point text; 10 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890
8 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

particularly in the primary colors. If the letters

6 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

5 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

4 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

are closed or badly “plugged” with ink, the 10 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890

printhead is laying down too much ink. A good- 8 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&* Thin line
6 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*
missing
quality print shows five vertical parallel lines of
5 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*
4 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

different thicknesses on the left and right side of 10 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890
8 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

the print. If the thinnest line is missing, the 6 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

5 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

4 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

printhead is outputting too much ink or the drum

10 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890
temperature is too high. 8 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

Causes:
6 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

5 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

4 point Times-Roman ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*

NOTE: Ensure that the printer is not in High

Resolution/Photo or Standard print
mode. s8500-051

Check the thermal regulation of the printhead

and of the drum. Make sure that the drum
temperature sensor is correctly mounted and in
proper, even contact with the drum. If
necessary, remove the sensor and check it for
an accumulation of debris at its contact point.
Replace the drum temperature sensor.
Ensure the printhead drive voltage is set to the
default 128.

Print-Quality Troubleshooting 5-35

Test Print Examples (Continued)
Big Bands OHP
This print allows you to evaluate transparency
printing. It prints two transparencies from
Tray 1, one with primary color fills and one with
secondary color fills and a band of 50% blue, as
this is a popular background color for overhead
transparencies.
Look for: Scratching on the print. Uniformity of
fill with no scratching.
Evaluate the print on an overhead projector.
Some print artifacts visible on the print do not
show when projected. Likewise, some defects
do not show until projected.
Causes: Confirm that you are using the
transparency that is supported for this printer.
Clean or replace the paper release blade. For
more information about scratches, see
"Scratches or Marks Parallel to the Long Axis of
Printing, Particularly with Film" on page 5-13.

s8500-052

5-36 Phaser 8400/8500/8550 Color Printer

Test Print Examples (Continued)
Gray Fill, Dot Size Uniformity
This print is made up of a 66% black fill. It
reveals variations in the ink-drop-spread
Light band
caused by thermal variations, transfix roller
pressure variations, or drum oiling variations.
Look for:
1. Large area of differences in the density
across the width of the page. (A slight
variation is normal.) Look for a lighter
vertical band, about 1/3 the width of the
page, running the length of the page. Also,
look for small, light spots, or irregular white
lines, vertically aligned with each other, in
the print every 125 mm (5.0 in.). Uneven fill
2. Also, look for ink on the top and bottom
Should see
margin of the page, or ink on the back of even fill
the page. This pattern is sensitive to the left to right
density variations in the paper it is printed
on. Use a high-quality grade of printer
paper; otherwise, the print appears
s8500-05
mottled.
Causes:
1. Use the diagnostics to check the printhead and drum for correct thermal regulation. Ensure
the drum fan is running properly. A vertical band, 1/3 of a page wide, running the length of
the page, is caused by a stuck heating plate in the paper preheater. Run the Control Panel
cleaning procedure Clean Print Smears, which raises the temperature of the paper
preheater and may free the stuck heating plate. Additionally, you may manually force a thick
sheet of paper (65 to 80 lb.) through the paper preheater to jar the plate free. Light spots
that repeat every 11.63 cm (4.58 in.) down the length of the page are caused by a defective
transfix roller. The roller has a soft spot that is not pushing the ink into the paper as well as
the rest of the roller. If you observe variations in the glossiness of the print, replace the
maintenance kit.
2. If there is ink on the top and bottom margin of the page or ink on the back of the page, it
may be caused by the roller remaining down during the print. You may hear an unusual
noise if the Transfix Roller stays down and rubs against the drum. Inspect the Drive Train
and ensure that it self-homes between prints. The drive train is in its home position when
the two 1.5 mm holes found on the clear plastic cover align axially with corresponding holes
in the gear. Another way to verify that the drive train is in its home position is to verify that
the two small leaf springs from the clear plastic cover are seated correctly in their
corresponding gear detent slots. Inspect the perimeter of the cam lobes for surface defects
and check to see that the angular orientations of the cams match. Inspect the transfix load
arm return springs. Verify that the maintenance kit returns home between prints. Inspect
the cam shaft surfaces for damage. If all of these items are working correctly, replace the
process drive module.

Manuf. Five Duplex GSF

This print is used by Manufacturing and
Engineering.

Print-Quality Troubleshooting 5-37

Test Print Examples (Continued)
YMCKRGB Solid Fills
These seven prints show uniformity of fill. If
colors are uneven or wrong, see "Color is
Uneven or Color is Wrong" on page 5-9.
Look for:
1. Even, uniform fills throughout each print.
2. Wrinkles or deformity of the paper itself
caused by the print process show up in
duplexed solid fill prints at Standard or
Enhanced resolutions. To test for wrinkling,
print the YMCKRGB prints in duplex mode at
the Enhanced or High Resolution/Photo
mode. Typically wrinkling appears in the
secondary colors. See the blue and green
solid fills in the illustration to the right.
Causes:
1. Weak jets or uneven drum heating may
cause uneven fills.
2. To solve wrinkling, try different print media.
Replace the maintenance kit to correct
streaking. Check the drum temperature
s8500-054
sensor for debris build-up on the sensor.
Check to see if the sensor is in improper
contact with the drum. See the Reverse Text
test print. As a last resort to fix wrinkling,
replace the transfix roller, transfix load
module, and transfix load arm.

Drum Seal
(8400 only)
This print is not supported for this printer.

Manuf. Paper Path

These prints are used by Manufacturing and
Engineering.

5-38 Phaser 8400/8500/8550 Color Printer

Test Print Examples (Continued)
Head-to-Drum Gap
(8400 only)
These prints indicate if the gap between the
printhead and the drum is correct.
Lines: The horizontal lines of the print are
made up of long and short dashes. Inspect the
first and last 1/2 in. (12 mm) of the black lines
EFGHIJKLMNOPQ
for the vertical distance between the short
dashes and long dashes.
EFGHIJKLMNOP
A difference indicates the printhead gaps at FGHIJKLMNOPQ
each end of the printhead are not equal. EFGHIJKLMNOPQ
EFGHIJKLMNOP
Text: Examine each end of the band of text. EFGHIJKLMNOP
Look for fuzziness or differences between the
quality of the characters on the left and right
ends of the print.
A difference indicates the printhead gaps at
each end of the printhead are not equal.

The ends of this printer’s printhead rests on two

spacers on the ends of the drum that hold the
head-to-drum gap under much tighter control
than in previous solid ink printers. There is no
head-to-drum adjustment possible in this
printer. If the gap is suspect, check that the
printhead is correctly and completely installed.

s8500-055

Manuf X-Axis (Scanner)

(8400 only)
This print is used by Manufacturing and
Engineering.

Print-Quality Troubleshooting 5-39

Test Print Examples (Continued)
Black, Red, Green, Blue, Cyan,
Magenta, and Yellow Solid Fills
This prints show uniformity of fill.
Look for:
1. Even, uniform fills throughout the print.
2. There should be no wrinkling or deformity of
the paper throughout the print.
3. Poor transfer on one side.
4. Repeating white stripes.
Causes:
1. Weak jets or uneven drum heating may
cause uneven fills.
2. To solve wrinkling, try different print media.
Replace the maintenance kit to correct
streaking. Check the drum-temperature
sensor for debris build-up on the sensor or
the sensor is not in proper contact with the
drum. See the test print Reverse Text.
3. If there is poor transfer on one side, check to
see if the transfix load arm assemblies are s8500-056
moving easily. Clean any contamination that
may be interfering with the transfix arm
assembly movement. If either of the transfix
load arm assemblies are worn, replace the
worn load arm assembly.
4. If there are repeating white stripes on the
print, there may be a problem with the X-Axis
motion, see“White Stripes (Pinstripes)” on
page 30.

OHP Color Bands

(8400 only) This print is used by
Manufacturing and Engineering.

5-40 Phaser 8400/8500/8550 Color Printer

Test Print Examples (Continued)
Primary Solid Fills 10x
This item enables you to print 10 cyan solid fill
prints, 10 magenta solid fill prints, 10 yellow
solid fill prints, or 10 black solid fill prints. These
prints can be used to determine if the drum or
transfix roller have a defect.
Drum defects do not move in the X-position
print-to-print; but it does move into the
Y‘-position print-to-print. Drum defects do not
repeat down the page.
Transfix Roller defects do not move in the
X-direction; but, these defects repeat every
4.58 in. (11.63 cm) down the length of the
page. Many Transfix Roller defects will be most
visible on duplex solid fills.

Print-Quality Troubleshooting 5-41

Test Print Examples (Continued)
Manuf. Skew Margins
This print consists of an image used by
manufacturing to gauge skew and margin on
2 sided prints.
Skew
To measure skew: the measurement between
the edge of the paper and the magenta frame

1
MM
should be within tolerance along the entire
length of the top of the paper. For example, the

2
measurement on the top left side of the sheet
should be the same as the measurement on the

3
top right side of the sheet (within tolerance).
To calculate skew: measure the margin at the
leading edge of each corner, then take the
difference between them. For example, if the
margin at the right leading edge corner is
5.1 mm, and the margin at the left leading edge
corner is 4.9 mm, then the skew would be (5.1 -
4.9) = 0.2 mm. The skew tolerance for the
following media types are: 8400 145
All sizes except envelopes and custom sizes:
0.0 +/- 0.89 mm
Envelopes: 0.0 +/- 1.04 mm
Custom media: evaluate with the following
formula: Skew Spec (mm) = 998.4*(width-
1
MM

12.5)^(-1.02), where width is in millimeters.

2

To measure margin, measure from the magenta

frame to the edge of the paper at the midpoint
3

on the top and left-edge margin (right side of

paper, left side of printer) of the paper.
The tolerance for margin is the margin +/- 2.
See the Media Margin Specification in the
Appendix. 1 2 3
MM

NOTE: The measurement for skew and margin

for Side 1 and Side 2 may not match
Check: The media must be supported for the
tray. The side and rear guides must be adjusted
to the size of the paper to ensure correct
deskewing. s8400-201

If you have skew on simplex prints, in Tray 2, 3,

or 4, check for a worn take away roller or pick
roller; in Tray 1, check for a worn pick roller.
This test print uses the tray selected in Paper
Source on the Paper Handling Menu.
If you have skew on duplex prints, check for a
worn duplex roller an verify that the front door is
completely closed and latched on both the left
and right sides.
If the lead-edge margins are outside of
tolerance, check the preheater flag.

5-42 Phaser 8400/8500/8550 Color Printer

Test Print Examples (Continued)
Manuf. Banding
(8400 only)
This print is used by Manufacturing.

Head Roll
(8400 only)
This print is used by Manufacturing.

Head Height
(8400 only)
This print is used by Manufacturing and
Engineering.

X Dot Position
(8400 only)
This print is used by Manufacturing and
Engineering.

Y Dot Position
(8400 only)
This print is used by Manufacturing and
Engineering.

Chase Pages
A blank piece of paper is used to remove
contamination from the drum, transfix roller,
and paper path.

Oil Bar Chase

This print is used by Manufacturing.

Purge Efficiency
This print is used by Manufacturing and
Engineering.

Print-Quality Troubleshooting 5-43

Test Print Examples (Continued)
Cleaning Page
This page is automatically printed following a
purge. It is used to flush the jet nozzles of any
possible contamination or color mixed jets. It
can also be printed on its own.

s8500-058
s8400-162

5-44 Phaser 8400/8500/8550 Color Printer

Adjustments and
Calibrations
In this chapter...
■ Printer Component Homing Positions and Indicators
■ Printer Calibrations
■ Jet Substitution Mode

Section
6
Adjustments

Wiper Alignment Procedure

1. Remove the printer covers using the procedures that begin on page 8-4.
2. Remove the left head maintenance drive gear (see the following figure) by
removing the e-clip from the drive shaft.

Left Idler Gear

Left Drive Gear

s8500-059

6-2 Phaser 8400/8500/8550 Color Printer

 3. At the same time, rotate the left and right idler gears until the wiper is all the way
to the bottom and the gears cannot be rotated further. Rotating the left and right
gears together ensures that the wiper stays parallel and does not pop out of the
belts.

Wiper assembly at bottom Wiper skewed when lowering.

of travel. Wiper not skewed.

Rotate left and right idler

gears to lower wiper.

s8500-060

4. Replace the left drive gear and the e-clip.

Adjustments and Calibrations 6-3

Printer Component Homing Positions and Indicators
After servicing the printer, manually set the following assemblies to their home
position before powering on the printer. If the assemblies are not home, gears in the
process drive assembly can grind or the printer can generate errors.

■ Printhead (tilted forward and disengaged from tilt gear)

■ Tilt gear (disengaged from process drive train; arrows on left frame point to
each other)
■ Printhead wiper (bottom of travel)
■ Process drive assembly (holes on transfix camshaft and drum maintenance
camshaft line up with marks on frame, large gears within assembly line up
with holes in assembly housing)

Wiper Assembly Positions

When the wiper is homed, the wiper should be moved all the way to the bottom of the
printer. When the wiper is at the bottom, you can easily remove the waste tray. See the
"Wiper Alignment Procedure" on page 6-2.

6-4 Phaser 8400/8500/8550 Color Printer

Homing the Head Tilt Gear

The Printhead Is Not in the Printer

If the printhead is not in the printer, move the tilt gear, located on the inside of the left
frame, manually to its disengaged position.

Drum

Printhead

Tilt gear (disengaged)

DM Cam Gear

Tilt Gear

s8500-061

Adjustments and Calibrations 6-5

The Printhead Is in the Printer
1. Remove the maintenance kit.
2. Insert a flat blade screwdriver into the end of drum maintenance cam shaft and
rotate clockwise one revolution. If the printhead is engaged, manually assist the
movement of the printhead.

Note
The hole on the drum maintenance camshaft drive gear should be at the 6:00
position after the rotation.

Insert
screwdriver
and rotate
clockwise.

Drum
maintenance
camshaft
gear

s8500-062

6-6 Phaser 8400/8500/8550 Color Printer

Note
When the tilt gear is disengaged, the two arrows on the left side of the printer are
pointing at each other.

Tilt Gear Disengaged Tilt Gear Engaged

s8500-063

Adjustments and Calibrations 6-7

Homing the Process Gear Drive Train
Examine the process gear drive train for the following:

■ The holes is the process drive frame must align with the holes in the gear.

■ The hole in the drum maintenance camshaft gear must align with the arrow on the
frame.

■ The hole in the transfix camshaft gear align with the hole on the frame.

6-8 Phaser 8400/8500/8550 Color Printer

 When installing or
homing the Process
Gear Train, ensure
the pivot plate is
fully engaged to the
drum maintenance
cams by pushing the
Drum Maintenance
Holes in process
Unit to the left.
drive frame aligns
with holes in
gears

Hole in gear
aligns with
arrow on Hole in gear
frame aligns with
arrow on frame

s8500-064

When correctly homed, slightly rotating the drum maintenance camshaft in either
direction should result in a proportional movement of the Drum Maintenance Unit -
with no delays or lags.

Adjustments and Calibrations 6-9

Printer Calibrations

Wiper Alignment
See the Wiper Alignment Procedure on page 6-2.

Jet Substitution Mode

On Phaser 8400 printers, the Jet Substitution Mode provides a temporary solution for
print-quality problems when weak or missing jets cannot be recovered. When Jet
Substitution Mode is active, adjacent jets are used to print over the area covered by
the problem jet to restore the print-quality. Jet Substitution Mode reduces the
maximum imaging speed by 50% or more and has other limitations that affect printer
performance.
Jet Substitution Mode on Phaser 8500/8550 printers is in the Eliminate Light Stripes
menu. Although it does not slow down the imaging speed as it does on Phaser
8400 printers, it still provides an end solution to eliminating light stripes.

Note
Always refer to the infoSMART Knowledge Base to access the latest guidelines
for using Jet Substitution Mode.

Phaser 8500/8550 printers feature a Jet Substitution mode that is similar to Phaser
8400 printers, but with two important differences:

■ Phaser 8500/8550 Jet Substitution mode can provide an end solution instead of
serving as a temporary fix (as for Phaser 8400 printers). Because Jet Substitution
mode can provide an end solution, it is located in the “Eliminate Light Stripes”
menu instead of requiring a hidden push button sequence, as is the case with
Phaser 8400 printers.

■ Most Phaser 8500/8550 users will not notice changes to print-quality or speed
when using the Jet Substitution mode. It typically increases the imaging time by
no more than one or two seconds per page compared to a 50% increase on Phaser
8400 printers.

The knowledge base provides new procedures for determining when to use Jet
Substitution mode. Factors such as the use of the Billing Meters feature and multiple,
adjacent problem jets can affect the recommended solution.

6-10 Phaser 8400/8500/8550 Color Printer

Enabling Jet Substitution Mode (8400)
To add Jet Substitution Mode to the Control Panel menu:
1. On the Control Panel, scroll to Troubleshooting, then press the OK button.
2. Scroll to Print Quality Problems, then press the OK button.
3. Press and hold the Up Arrow button, then press the Back button.

The Jet Substitution Mode is now displayed on the Control Panel.

To correct print-quality problems, refer to the Eliminate Light Stripes test page to
determine which jets are weak or missing.
1. Select Jet Substitution Mode, then press the OK button.
2. Select Jet Select, then press the OK button.
3. Scroll to the color for the weak or missing jet, then press OK to select the color.
4. Use the Up Arrow and Down Arrow buttons to select the number of the weak or
missing jet, then press OK to confirm the selection.
5. Select Save Change and Exit, and then press OK to complete the procedure.
6. After substituting a jet, print the Light Stripes Test page to verify the problem has
been solved.

At the bottom of the page, a Service Mode key summarizes the number of
substituted jets for each color.

Note
The Configuration Page and Printer Status Pages also provide a list of jets in
Service Mode.

Enabling Jet Substitution Mode (8500/8550)

To select Jet Substitution Mode for the Phaser 8500/8550:
1. On the control panel, select Troubleshooting, and then press the OK button.
2. Select Print Quality Problems, and then press the OK button.
3. Select Eliminate Light Stripes, and then press the OK button.
4. Select Jet Substitution Mode, and then press the OK button.
5. Follow the control panel prompts to select the color and malfunctioning jet
number indicated on the Light Stripes Test page.

Adjustments and Calibrations 6-11

Disabling Jet Substitution Mode (8400)
After the printhead is replaced, disable Jet Substitution Mode to restore normal
operation. Using the hidden Jet Substitution Mode Menu, select Jet Select.
1. On the Control Panel, select Troubleshooting, and then press the OK button.
2. Select Print Quality Problems, and then press the OK button.
3. Press and hold the Up Arrow button, and then press the Back button.
4. Select Turn Jet Substitution Mode Off, and then press the OK button.
5. Print the Eliminate Light Stripes test page to verify that Service Mode is disabled
for all jets.

Disabling Jet Substitution Mode (8500/8550)

After the printhead is replaced, disable Jet Substitution Mode to restore normal
operation. To deselect Jet Substitution Mode:
1. On the Control Panel, scroll to Troubleshooting, then press the OK button.
2. Select Print Quality Problems, and then press the OK button.
3. Select Eliminate Light Stripes, and then press the OK button.
4. Select Turn Jet Substitution Mode Off, and then press the OK button.
5. Print the Eliminate Light Stripes test page to verify that Service Mode is disabled
for all jets.

Resetting NVRAM
Resetting NVRAM returns all the Image Processor Board NVRAM-stored
parameters to their factory default values. The print counts and the Adobe firmware
serial number are not affected by this reset. You can reset the PostScript NVRAM
using the Service Tools Menu or the Service Diagnostics Menu.

6-12 Phaser 8400/8500/8550 Color Printer

Cleaning and
Maintenance
In this chapter...
■ Maintenance
■ Inspection
■ Cleaning

Section
7
Service Cleaning Maintenance Procedure
Cleaning your printer may be necessary if the printer is having print-quality or paper-
feeding problems. Some cleaning procedures, such as purging the jet nozzles are done
automatically when necessary. Other procedures, such as scrubbing the paper-feed
rollers with an alcohol-moistened, lint free wipe, must be done by customers, but only
if the rollers are visibly dirty.
Cleaning may be indicated by any of the following:
■ Light stripes or missing colors appear in prints.
■ Ink smears or random streaks appear on the front or back of prints.
■ Oily spots appear along the tops of prints.
■ Mispicks or multiple picks occur at the media tray.
■ Persistent paper jams inside the printer or at the media tray if the rollers are
visibly dirty.
■ Wiggly vertical stripes caused by too much oil created by a dirty
maintenance kit blade.
■ Most print-quality problems can be corrected by running the cleaning
procedures on the printer’s Control Panel menu.

Cleaning
Supplies Required

■ 90% pure isopropyl alcohol ■ Alcohol-moistened, lint-free wipes

■ Foam swabs ■ Clear packaging tape

Caution
Do not use rubbing alcohol because it can contain water and oils that leave
undesirable residue on the printer parts. Never use water to clean the printer’s
internal components.

Clean dust build-up on the exterior of the printer. Inspect the grills on the exterior of
the printer for dust. Clean if necessary

7-2 Phaser 8400/8500/8550 Color Printer

Appropriate cleaning procedures, as listed in the following tables, should be
performed when specific print-quality or paper transport problems occur.
All cleaning procedures are detailed in the printer’s Phaser 8400 Reference Guide or
the Phaser 8500/8550 User’s Guide.

Light Stripes or Missing Colors

Problem type Solution

Missing or light-colored Select the automated procedure Eliminate Light Stripes from
stripes on prints. the Control Panel.

Ink Smears, Oil Spots, or Random Ink Streaks

Problem type Solution

Ink smears on the front, Select the automated procedure Remove Print Smears from
back, or edges of a page. the Control Panel.
Check the maintenance kit for ink and paper-dust build-up on
the wiper blade.

Oil (drum fluid) on top edge Select the automated procedure Remove Print Smears from
of print. the Control Panel.

Media Jams:

Note
Refer to the jam codes in "Jam Codes" on page 3-55.

Problem type Solution

Paper-pick or jamming Clean the pick roller. Follow the "Pick Roller Cleaning Method"
problems at the tray. on page 7-4.

Paper jamming problems Clean the transport rollers.

at the front door.

Paper jamming problems Clean the exit rollers and paper release blade.
at the exit.

Paper-pick or jamming Clean the appropriate tray assembly feed roller.

problems at the Optional
525-Sheet Feeder, Tray 3,
or Tray 4.

Duplex path jam Clean the preheat, duplex, and exit rollers.

Double picks Clean the pick rollers and separator pad with alcohol. Clean
pick pad with clear packaging tape using the procedure "Pick
Roller Cleaning Method" on page 7-4.

Cleaning and Maintenance 7-3

Pick Roller Cleaning Method

Tray 1
Tray 1 pick roller can be cleaned with an alcohol moistened swab.
1. Open the front cover.
2. Rotate the roller and clean it with an alcohol-moistened swab.
3. Rotate the roller so that the flat side is facing down.
4. Close the front cover.

Trays 2-4
Use off-the-shelf clear packaging tape and follow the procedures listed below to clean
the pick roller and pick pad for Trays 2-4. This cleaning method has been found to be
extremely effective for removing debris. Isopropyl alcohol, while effective, tends to
smear the debris, rather than remove it.
1. Remove the tray with the paper-picking or paper jamming problem (Tray 2, 3, or
4).
2. Peel off a strip of tape. Stretch the tape across the table with the sticky side up.
Fasten it to the table at both ends.
3. Remove the roller.
4. Roll the roller across the tape to remove the debris from the roller.
5. Locate a clean section of the tape, rub it onto the surface of the pick pad for the
paper tray, then remove it.
6. Replace the roller.
7. Reinsert the tray.

Drum Temperature Sensor

With a dry swab, clean any buildup around the drum temperature sensor. You can
access the sensor through the opened exit cover. Also, make sure the sensor rides
evenly on the drum surface. You can remove the sensor, if necessary, to clean under it.

7-4 Phaser 8400/8500/8550 Color Printer

Maintenance

Maintenance Kit
The printer uses the Maintenance Kit as part of its self-maintenance routine to coat
the print drum with oil before each print.

Maintenance Kit Life

Standard/Startup P/N 108R00602 (8400 series)

Maintenance Kit Life The Phaser 8500 only supports the standard kit.
P/N 108R00675

Any Coverage* (8500/8550) 10,000 cycles for black and white, 5500 cycles
for color.

(8400) 10,000 cycles regardless of colors used.

Extended P/N 108R00603 (8400 series)

Maintenance Kit Life P/N 108R00676 (8550 series)

0 - 20% Coverage* 30,000

20 - 100% Coverage* 20,000-30,000

*The image coverage is determined by counting the number of pixels imaged.

A Control Panel message indicates when the maintenance kit is low. Printing is still
possible when the maintenance kit is low. When a Control Panel message indicates
that the maintenance kit is “empty,” the maintenance kit must be replaced before
continued printing is possible. Refer to the installation instructions included with the
maintenance kit.

Note
The maintenance kit fluid, an oil, poses no known adverse health effects. See the
Material Safety Data Sheet at www.xerox.com/office/msds.

Waste Tray
The waste tray collects ink that has been purged from the printer’s ink jets. A Control
Panel message indicates when the waste tray is full. Refer to the printer’s Phaser 8400
Reference Guide or the Phaser 8500/8550 User’s Guide for instructions on removing
and emptying the waste tray. A Control Panel message displays when the waste tray
needs to be emptied (usually after seven purges). Never reuse waste ink in the printer;
it will damage the printhead.

Cleaning and Maintenance 7-5

Lubrication
The printer is lubricated during assembly at the factory and requires no periodic
lubrication. Some parts require lubrication following replacement. These parts are
identified in the replacement procedures. When lubricating during replacement, use
the grease approved for all Phaser printers. The grease part number is 006-7997-00.

Caution
Plastic parts will deteriorate when unspecified grease and chemicals are used,
such as WD-40® and Locktite® Threadlocker. To avoid damage, use only the
grease specified in the Lubrication section of the Service Manual.

Inspection
Rollers: Replace the rollers when you see any of the following defects:
■ Flat spots
■ Out of roundness
■ Cracked rubber
■ Loss of traction (tackiness) causing pick or feed failures

Gears: Replace gears that show any signs of wear or breakage. Look for these
problems:
■ Thinned gear teeth
■ Bent or missing gear teeth; check especially where a metal gear drives a
plastic gear.
■ Fractured or cracked gears (Oil or incorrect grease on a plastic gear can
cause the gear to crack.)
Belts: There are 3 rubber belts in the printer. Inspect the belts for wear.
Look for these problems:
■ Loose rubber particles below the belts indicate a worn belt.
■ Missing teeth in the belts
■ Cracking or moderate fraying; a small amount of fraying is inevitable, so
look for other signs of wear before replacing the belt.

7-6 Phaser 8400/8500/8550 Color Printer

Service Parts
Disassembly
In this chapter...
■ Overview
■ General Notes on Disassembly
■ Covers
■ Imaging
■ Paper Path
■ Motors, Gears, Solenoids, Clutches, and Fans
■ Electronics

Section
8
Overview
This section contains the removal and replacement procedures for selected parts of the
printer according to the Field Replaceable Units (Service Parts) Parts List. In general,
replacement procedures are not given because re-installing a part is usually simply a
reversal of the disassembly. Replacement procedures are included where this is not
the case and special steps are required. Replacement notes are included when they can
help ease or shorten the reassembly process.

Standard Orientation of the Printer

When needed the orientation of the printer is called out in the procedure for locating
printer parts. Refer to the printer orientation graphic for locating the right, left, front
and back sides of the printer.

Back
Left

Right

Front s8500-002

8-2 Phaser 8400/8500/8550 Color Printer

General Notes on Disassembly
Caution
Follow the steps of all disassembly procedures in the order given to avoid
damaging printer components.

1. Before servicing the printer, switch OFF the printer power, wait until the printer
completely shuts down, and disconnect the power cord from the wall outlet.
2. Wear an electrostatic discharge wrist strap to help prevent damage to the sensitive
electronics of the printer circuit boards.
3. Upon reassembly of printer components, be sure the components are all in their
home positions, otherwise damage to the printer will occur. See Chapter 6
Adjustments, Home Position page 6-2 for information on the home positions.

Special Notes Regarding Screws Used in This Equipment.

■ Screws in plastic are torqued to 12 in. lbs., metal to 15 in lbs., unless otherwise
specified. The screws for the printhead restraints should be torqued to 6 in. lbs.

■ Do not over torque the screws threaded into plastic parts.

■ Always use the correct type and size screw; coarse thread, brass-colored screws
into plastic and fine thread, silver-colored screws into metal.

■ Using the wrong screw can damage tapped holes. This applies to the yellow
reverse-threaded screws on the drum assembly.

■ Do not use excessive force to remove or install either a screw or a printer part. If
using a power driver to install a screw into plastic, start the screw by hand.

■ If you strip out threads in the plastic chassis, a silver-blue-tinted thread repair
screw (included in the hardware kit) can be used to correct the problem.

■ If you remove a silver-blue-tinted thread repair screw during disassembly, replace

the screw the same location or additional damage to the printer will occur.

Warning
Unplug the AC power cord from the wall outlet before removing any printer part.

Notations in the Disassembly Text

■ The notation “(item X)” points to a numbered callout in the illustration
corresponding to a part or step being performed.

■ The notation “PLX.X.X” indicates that this component is listed in the Service
Parts List.

■ Bold arrows in an illustration show direction of movement when removing or

replacing a component.

Service Parts Disassembly 8-3

Covers

2
5

Tab

Tab

Tab
9

s8500-068

1. Front Door, Tray 1 (MPT) 6. Exit Cover

2. Control Panel Cover 7. Ink Loader Assembly and Door

3. Control Panel 8. Interface Cover

4. Right Side Cover 9. Side Door

5. Left Side Cover

8-4 Phaser 8400/8500/8550 Color Printer

Front Door (Tray 1) Assembly
(PL 1.1)
1. Open the Front Door assembly (Tray 1) by pulling out on the handle to the right
side of the door.

s8500-065

2. Remove the right and left stay retainers from the Front Door (MPT).
3. Open the plug cover and disconnect the plug from the right side of Front Door
(Tray1/MPT).
4. Free the plug wiring from cable retainer on the right side of Front Door (MPT).
5. Carefully remove the Front Door (Tray 1/MPT) assembly (PL1.3), by releasing
the left hinge pin (PL1.4) from the printer frame and sliding the assembly to the
right to remove it.

Stay Retainer
1

Stay Retainer
3 s8500-066

Note
Do not lose the hinge pins or stay retainers for the front door.

Service Parts Disassembly 8-5

Control Panel Cover
(PL 1.5)
1. Open the Exit Cover.
Exit Cover

Control Panel Cover

Control Panel
Open exit cover from Cleaning Kit
Front Door

s8500-067

2. Using either your fingers or a small flathead screwdriver, loosen the Control
Panel Cover on the left side and then slide it forward and lift up to remove it from
the printer.

Front (Control) Panel

(PL 1.7)
1. Remove the Control Panel Cover (as directed above).
2. Disconnect the two wiring harness connectors and one ribbon cable connector
from the back of the Control Panel.
3. Remove the Control Panel (see Covers figure on page 8-4).

Right Side Cover

(PL 1.10)
1. Open the exit cover.
2. Remove the Control Panel Cover (as directed above).
3. Open the Front Door.
4. Remove the rear screw.
5. Pull forward on the latching tab located by the power plug (see Covers figure on
page 8-4) to release it.
6. Release the front latching tab and pull out on the top to remove the Right Side
Cover.

8-6 Phaser 8400/8500/8550 Color Printer

Left Side Cover
(PL 1.9)
1. Remove the Control Panel Cover.
2. Open the Exit Cover and Front Door.
3. Remove the rear screw.
4. Release the latching tabs (see Covers figure on page 8-4) and remove the Left
Side Cover.

Exit Cover
(PL 1.7)
1. Remove the Right and Left Side Covers.
2. The exit cover (see Covers figure on page 8-4) will now just lift off the printer.

Replacement Note:

Note
Lift the upper exit guide slightly, and engage the pins on the upper exit guide
with the slots on the Exit Cover before inserting the cover hinge pins into the
pivot points in the printer frame.

Service Parts Disassembly 8-7

Ink Loader Assembly and Door
(PL 1.8)
1. Remove the Right and Left Side Covers (page 8-6) and the Exit Cover (page 8-7).
2. Lift the Ink Loader Assembly clear of the chassis and hold it in position against
the rear of the chassis to allow access to the connectors. For Phaser 8400 printers,
the Ink Loader disconnects from the printer frame. For Phaser 8500/
8550 printers, the wiring harness that plugs into the right side frame disconnects
directly from the Ink Loader.

Note
Hooks on the bottom of the Ink Loader Assembly allow it to hang on the rear
of the printer chassis while the connectors are removed.

3. Disconnect the two Ink Loader harness connectors from the printer chassis and
remove the Ink Loader, Assembly and Door as one unit.

8400

8500/8550

s8500-069

8-8 Phaser 8400/8500/8550 Color Printer

Replacement Note:

Note
For the Phaser 8400, the gray cable from the side chassis must be routed
between the Ink Loader and the printer side. The cable from the ink loader
must be routed towards the left side (see inset). For the Phaser 8500/8550,
the cable comes from the side of the chassis and plugs directly into the
inkloader. After replacing the Phaser 8500/8550 ink loader, use the hidden
Service menu to reset the ink stick count.

Imaging

Y-Axis Belt, Y-Axis Tension Spring, and Y-Axis Motor

Assembly
(PL 2.4) (PL 2.14) (PL 4.4)
1. Remove the left side cover (see page 8-7).
2. Relieve tension on the belt by pulling the end of the spring arm toward the front
of the printer using your fingers.
3. Slide the belt off the pulley.

Y-Axis Belt

Y-Axis Tension Spring 2

s8500-070

Service Parts Disassembly 8-9

 4. Using a spring hook or pliers, remove the Y-Axis tension spring from the chassis
retainer and the spring arm. Brace the printer to keep it from moving during
removal of the spring.

Warning
Safety glasses recommended for Step 4.

Caution
This is a strong spring that can cause damage if it slips during removal; use
extreme caution when removing.

5. Move the wires out of the way.

6. Disconnect the motor wiring harness connector from the printer.
7. Remove four screws (three coarse thread and one fine thread) from the spring
arm. The three screws securing the arm to the motor remain in place.

20 in-lbs.

Y-Axis Motor Assembly

s8500-071

8. If replacing the motor, remove 3 motor screws to separate the motor from the arm
and remove the spring arm.

8-10 Phaser 8400/8500/8550 Color Printer

Replacement Notes:

Note
Ensure the spring arm screws are in the right locations and that the arm floats
freely. Also, torque the screws connecting the spring arm to the motor to 20
in.-lbs.

Caution
Ensure that the ground lug is replaced on the mounting screw (see figure
above) during replacement.

Service Parts Disassembly 8-11

Printhead Assembly, Right and Left Printhead
Restraints
(PL 2.4) (PL 2.5 and 2.6)
Videos are available with instructions for replacing the printhead
assembly. Videos are located on the Phaser 8400/8500/8550 Product
Training CD-ROM. Select Service and then select Printhead
Procedures.

Warning
The printhead is hot when the printer is operating. Turn off power to the
printer and allow the printhead to cool for 30 minutes before starting
removal procedure.

Caution
Perform the steps in this procedure in the order given to prevent damage to
the printer.

1. Remove the ink loader assembly and door (see page 8-8).

Caution
Place several sheets of paper between the faceplate of the printhead and the
drum to protect the drum from damage.

2. On the right side of the printer, lift up on the Wiper Assembly Lock (#1 on the
figure below) to unlock the Wiper Assembly gear train.
Wiper Assembly Lock Gear

Printhead Restraint
Printhead Restraint Arm

Printhead

Printhead
Restraint

Printhead Restraint Arm s8500-073

8-12 Phaser 8400/8500/8550 Color Printer

 3. Rotate the gears as shown by #2 above to lower the wiper all the way down.

Caution
To prevent damage to the ink jets, be careful not to place your fingers on the
faceplate of the printhead.

4. While pulling back slightly on the printhead to keep it away from the drum
surface, unlock (push down) the right and left printhead restraint arms, #3 above,
then slowly allow the spring-loaded printhead to tilt forward.
5. On the left side of the printer, pull the X-Axis bias spring and hook out slightly
and shift to the side (rotate down), see #1 and #2 of the following figure. Allow
the spring hook to rest against the detentes in the printer frame.
Purge Pump Bias Spring Hook

1. 2.

s8500-074

6. Disconnect the air hose from the purge pump (see figure above).

Service Parts Disassembly 8-13

 7. Remove left and right printhead restraints. First remove the screw, then pull
inward towards the printhead, then lift up and slightly toward the rear of the
printer to remove (see figure below).
Printhead Restraint

When reassembling,
torque to 6 in/lbs (1 N-m)

Printhead Restraint s8500-075

Note
Adjust printhead position as required to remove the right restraint.

8. Remove the Roll Block on the left end of the printhead shaft.

Caution
The roll block may be hot if the printer was just shut down.
Printhead Shaft

Roll Block s8500-076

8-14 Phaser 8400/8500/8550 Color Printer

 9. Disconnect the heater harness plug and free the harness (see the following figure)
from its restraint.
Finger Holes
Cable Restraint
Cradle Notch

Flex Cable

Flex Cable (8400 Only)

Data Cable

Heater Cable
EMI Tape
Heater Harness Plug (8500/8550)

Ground Strap (8500/8550 Only)

s8500-077

Service Parts Disassembly 8-15

10. Lift the printhead out of its mounting position and place the shaft ends in the
cradle notches near the top of the chassis frame (see the following figure).
Cradle Notches

s8500-078

11. Disconnect the data cable from the print head (see the figure above).
12. Disconnect the flex cable from the printhead (Phaser 8400 printers have two
cables).

Warning
Do not pinch or tear the air hose while removing the printhead as this will
damage the printer.

13. Lift the printhead free of the printer chassis.

Replacement Notes:
The following replacement steps are basically the reverse of the disassembly steps
and provide important precautions.

Caution
To avoid damage observe the following order when reinstalling the
printhead.

1. Ensure that the tilt gear is in the home position (see page 6-5).
2. Rest the printhead on the cradle notches provided (see the previous illustration)
while reconnecting the cable and flex connector.

8-16 Phaser 8400/8500/8550 Color Printer

 3. Insert the ribbon cable fully and squarely into the flex connector.

Caution
Ensure that the flex cable is inserted into the flex connector on the printhead
fully and squarely. If the cable is not inserted incorrectly, it can short out the
Wave Amp.

4. Connect the data cable connector and heater harness connector.

Warning
The printhead heater cable not only needs to be routed through the cable
restraint, but also needs to be clear of the printhead to prevent interference
which would result in errors 7009 and 4025 fault codes.

Caution
Before reinstalling the printhead, move the wiper all the way down.

5. Lower the printhead into its mounts. The printhead should be tilted forward in the
print position.

Caution
Be sure to remove any sheets of paper that you placed between the faceplate
of the printhead and the drum during disassembly.

6. Route the air hose through the frame and connect it to the purge pump.
7. Install the Roll Block on the left end of the printhead Shaft. The Roll Block must
be oriented as shown on the paper label on the left side of the printer frame.
8. Install the left and right printhead restraints. Be sure to tighten the screws to 6 in.
lb. to avoid stripping the chassis threads.

Caution
Ensure that the tilt spring on the left restraint is properly positioned in the
notch on the back of the printhead and does not pinch the air hose.

9. Set the X-Axis bias hook and spring on the end of the left printhead shaft. Ensure
that the point of the hook is centered in the shaft and the rest of the hook floats
freely.
10. After completing the installation, print the Light Stripes Page and check for jets
in service mode. If necessary, use the Control Panel to reset the jet substitution
mode.

Service Parts Disassembly 8-17

Head Tilt Solenoid
(Phaser 8500/8550 only)
(PL 4.12)
1. Remove the left side cover (see page 8-7) and the right side cover (see page 8-6).
2. Remove the printhead (see page 8-12).
3. Lower the wiper blade to its lowest position.
4. From the chassis left side, disconnect the connector attached to the head tilt
solenoid.
5. Remove the screw from the head tilt solenoid, then swing the unit out to the left
until the solenoid is free from the chassis.

Head Tilt Solenoid

s8500-079

Note
Be careful not to lose the restraining spring from the unit.

Replacement Notes:
Caution
To ensure proper operation of the printhead, observe the following order
when reinstalling the head tilt solenoid.

1. Insert the plastic end of head tilt solenoid into the chassis, swing to the right and
replace the screw in the chassis.
2. Using a screwdriver from the right side of the chassis, turn the lower screw of the
process drive clockwise until you hear the tilt head solenoid snap into place.

8-18 Phaser 8400/8500/8550 Color Printer

X-Axis Bias Spring
(PL2.19)
1. Remove the printhead (see page 8-12).

Caution
The spring is in close proximity to the drum. Be careful with the removal
tools and the spring to ensure that you do not damage the drum.

2. Using your hands, a spring hook, or pliers, remove the X-Axis bias spring from
inside the printer cavity.

X-Axis Bias Spring

s8500-080

Replacement Note:

Note
Do not rotate the spring more than 1/4 turn.

Service Parts Disassembly 8-19

Printhead Wiper
(PL 2.7)
Videos are available with instructions for replacing the printhead
assembly. Videos are located on the Phaser 8400/8500/8550 Product
Training CD-ROM. Select Service and then select Replacement
Videos).

1. Remove the printhead (see page 8-12).

Caution
Place several sheets of paper between the printhead and the drum to protect
the drum from damage.

2. Using the gears, position the wiper blade all the way up.
3. On the left side of the printer remove the KL clip and gear as shown below.
KL-Clip

Large Drive Gear

Wiper Belt

Wiper Clip s8500-081

8-20 Phaser 8400/8500/8550 Color Printer

 4. Remove the left plastic clip from the wiper belt and slide the wiper off of the belt.

Note
For the early model Phaser 8500/8550 printer, insert a small flatblade
screwdriver between the backside of the left wiper clip and the flat side of
the belt (see lower inset of the previous illustration). Applying a small
amount of pressure against the plastic wiper clip with the screwdriver, you
can gently slide the wiper off the belts.

Replacement Note:
1. Position the wiper so both ends are all the way down following reassembly (see
"Wiper Alignment Procedure" on page 6-2).
2. When reinstalling the belt into the wiper clip in the Phaser 8500/8550 printer,
place the belt partly on the clip, and then press the center of the clip with a small
needle-nose plier until the belt is secured in the clip.

Wiper Belt

Wiper Clip

s8500-082

Later versions of Phaser 8500/8550 serial numbered WYN1xxxxx or WYP1xxxxx

use the wider style wiper drive belt and wiper of the Phaser 8400. Refer to the Service
Bulletin 701 for more information.

Service Parts Disassembly 8-21

Media Release Blade Carriage Assembly and Transfix
Roller
(PL 2.13)
Videos are available with instructions for replacing the Transfix
Roller. Videos are located on the Phaser 8400/8500/8550 Product
Training CD-ROM. Select Service and then select Transfix Load
Module Procedures).
1. Remove the Right Side Cover (see page 8-6).
2. Disconnect J250 from the I/O Board.
3. Remove the Control Panel cover.
4. Remove two screws securing the I/O Board to the chassis, slide the board towards
the rear, and move the board out of the way.
5. Loosen the screw securing the Transfix Roller Shaft Restraint and remove the
restraint.

Caution
Hold the Transfix Roller and the Media Release Blade with one hand during
removal to prevent the Transfix Roller from falling and damaging the printer.
Also, do not use the transfix roller shaft restraint as a lever to pry the shaft.
Doing so can bend the restraint.

6. Use the end of the Transfix Roller Shaft Restraint to pull the shaft out and remove
the shaft from the printer (see figure on the next page).
7. Remove the Media Release Blade and Transfix Roller.

s8500-083

8-22 Phaser 8400/8500/8550 Color Printer

Paper Preheater and Deskew Assembly
(PL 2.17)
1. Open the Front Door.
2. Remove the Lower Duplex Guide (see page 8-41).
3. Remove the Inner Simplex Guide (see page 8-41).
4. Unplug the AC and sensor flag connectors from the bottom of the Preheater.

Note
Release the lock on the back of the AC connector.

AC Connector

Sensor Flag Connector s8500-084

5. Slide the latches in and forward to latch in their slots as shown by (1) and (2) in
the following figure.

Service Parts Disassembly 8-23

 6. Slide the Preheater off the shelves and out of the printer as shown by (3).

Note
Phaser 8500/8550 preheater is more difficult to slide out than the Phaser 8400
preheater because there is less clearance with the Preheater Lift solenoid.

Latches

1
1 2
2
3

s8500-085

Replacement Note:

Note
The fingers on the Inner Simplex Guide, go over the segmented roller. First
snap the left retainer into place, then the right.

8-24 Phaser 8400/8500/8550 Color Printer

Duplex Roller
(PL 3.10)
1. Open the Front Door.
2. Remove the upper and lower duplex guides (see page 8-41).
3. Remove the Duplex Roller by removing the left KL-clip on the shaft and sliding
the left side bearing down the shaft toward the right (1). Then slide the shaft
toward the left (2) to free the right end of the shaft. Finally, pull the shaft out
towards the right side of the printer (3).

KL-Clip

3
1

Bearing

s8500-086

Service Parts Disassembly 8-25

Transfix Load Module
(PL 3.9)
Videos are available with instructions for replacing the Transfix Load
Module assembly. Videos are located on the Phaser 8400/8500/8550
Product Training CD-ROM. Select Service, and then select Transfix
Load Module Procedures.

1. Remove the Front Door (MPT) assembly (see page 8-4).

2. Remove the Ink Loader Assembly and Door (see page 8-8).
3. Remove the Paper Preheater (see page 8-23).

Note
You don’t need to remove the preheater if the transfix ground springs are put
on after the load module is installed.

4. Remove the Media Drive Gearbox (see page 8-48).

Note
Step 4 is not required if you are only removing the Duplex Roller.

5. Remove four screws, disconnect two connectors, and remove the Exit Module
(see page 8-40).
6. Remove the upper and lower duplex guides (see page 8-41).
7. Remove the Duplex Roller by removing the left KL-clip on the shaft and sliding
the left side bearing down the shaft toward the right (1) (see preceding figure).
Then slide the shaft toward the left (2) to free the right end of the shaft. Finally,
pull the shaft out towards the right side of the printer (3).

8-26 Phaser 8400/8500/8550 Color Printer

 8. Insert a T-20 Torxbit through the slotted hole in the Transfix Load Module,
engage the hole on the back of the module, and gently lever the module’s spring
cam toward the center of the printer to release/unhook the spring hooks from the
Transfix Load Arms. Slowly relax the lever to return the spring cam to the
relaxed position.

Caution
Ensure that you lever the spring cam towards the center. Applying the
pressure in the wrong direction can damage the Transfix Load Module. Also,
placing too much force in the leverage action could destroy the cam.

Transfix Load Module

s8500-087

Service Parts Disassembly 8-27

 9. Remove the clevis pins (1) securing the Transfix Load Arms (2) to the chassis,
and remove the Transfix Load Arms and Transfix Roller.

Clevis Pin

Transfix Load Arm

Add Grease

s8500-088

10. Remove the Transfix Camshaft (see page 8-31)

8-28 Phaser 8400/8500/8550 Color Printer

11. Remove the grounding springs from the Transfix Load Module.

Grounding Springs

s8500-089

12. Remove two screws securing each end of the Transfix Load Module to the
chassis.

Transfix Load Module

s8500-090

Service Parts Disassembly 8-29

13. Remove the Transfix Load Module by rotating the bottom in and pulling it
forward.

Note
The Transfix Load Module is a very tight fit, remove carefully.

Transfix Load Module

s8500-092

Replacement Notes:

Note
Place a small amount of Rheolube 768 grease (P/N 00679900) in the groove
on the end of each Transfix Load Arm (see figure at Step 9) before
reattaching the spring hooks.

Note
After installing the Exit Module, perform the Wiper Alignment (see
page 6-2). The printer may report error code 7,009.4x if the wiper assembly
is misaligned.

8-30 Phaser 8400/8500/8550 Color Printer

Transfix Camshaft Assembly
(PL 3.8)
1. Perform Steps 1 through 7 (remove Transfix Load Arms) of the Transfix Load
Module removal procedure (see page 8-26).
2. Remove the Process Drive Gearbox assembly (see page 8-51).
3. Slide the shaft to the right (1) and make sure the bearing slides over to the gear,
move the shaft down and slightly to the right (2) and then up and to the left (3) to
remove it from the printer chassis cavity.

2
Transfix Camshaft

1
3

s8500-093

Service Parts Disassembly 8-31

Drum Maintenance Camshaft Assembly
(PL 2.11)
1. Remove both the Drum Maintenance Pivot Plate Assembly (see page 8-33).
2. Remove the Process Drive Gearbox assembly (see page 8-51).
3. Slide the shaft to the right, free the bushing, and remove the shaft to the right.
4. Carefully pry the bushing out of the right ground plane.
5. Rotate the left end of the shaft slightly toward the rear of the printer, lift the shaft
through the slot, and pull it out to the right through the large hole.

Drum Maintenance Camshaft

Bushing

s8500-094

8-32 Phaser 8400/8500/8550 Color Printer

Drum Maintenance Pivot Plate Assembly
(PL 2.10)
1. Remove the Drum Maintenance Kit Assembly.
2. Remove both the Right and Left Side Covers (see page 8-6).
3. Remove the grounding clip on the right end of the Pivot Plate Shaft.
4. Remove the KL-clip on the right end of the Pivot Plate Shaft.
5. Remove the Pivot Plate Shaft.
6. Disconnect the connector from the I/O Board (black/white).
7. Feed the cable into the printer while sliding the Drum Maintenance Pivot Plate
out the drum maintenance drawer cavity.

Metal Plate

1
2 3 KL Clip

Grease Points
Grounding Clip

Metal Plate
s8500-095

Replacement Note:

Note
Lightly grease the metal plates on which the cams ride, using a small
quantity of Rheolube 768 grease (P/N 00679900). Also fill the pocket under
the shaft ground with grease.

Service Parts Disassembly 8-33

Drum Assembly
(PL 2.8)
Videos are available with instructions for replacing the Drum
Assembly. Videos are located on the Phaser 8400/8500/8550 Product
Training CD-ROM. Select Service and then select Replacement
Videos).

1. Remove the Front Door Assembly as described on page 8-4.

2. Remove Ink Loader Assembly, right and left side covers, and exit cover as
described on page 8-8.
3. Remove the lower inner duplex guide as described on page 8-41.
4. Ensure that the printhead is in park position (tilted back) and the Wiper Assembly
is in the home position (all the way down).
5. Insert a T-20 Torxbit through the right slotted hole in the Transfix Load Module,
engage the hole on the back of the module, and lever the module’s spring cam
toward the center of the printer to release/unhook the spring hooks from the
Transfix Load Arms. Slowly relax the lever to return the spring cam to the
relaxed position. (See the figure on page 8-27.) Repeat for the other side.

Note
Ensure that you lever the spring cam towards the center. Applying the
pressure in the wrong direction can damage the Transfix Load Module.

6. From the right side of the printer, remove 3 screws from the Drum Fan Assembly
and allow the fan to hang free.
7. Relieve tension on the belt by pulling the end of the spring arm toward the front
of the printer using your fingers. (See the figure on page 8-9.)
8. Slide the belt off the pulley.

Note
Refer to the illustration on the next page to locate the cables and connectors
listed in the remaining instructions.

9. Unplug the Drum Heater Cable from the Relay Board and free the cable from the
retaining hook.
10. Unplug the Drum Encoder Cable connector from the Power Control Left Cable
and free the cable from the retaining hook.
11. Unplug the Drum Thermistor Cable connector from the I/O Board.

8-34 Phaser 8400/8500/8550 Color Printer

12. Remove the Exit Module assembly (see page 8-40).

Exit Module Assembly

Media Release J850
Blade Assembly Drum Thermistor
Cable Connector to I/O Board
Transfix Load Arm

Drum Heater Cable

110 Connector (J250)

to Control Panel Cable
(Not Shown)

Drum Encoder Cable

Drum Heater
Relay Board

Power Control Left Cable s8500-091

Caution
The Drum Thermal Sensor Cable is routed through the Exit Module. Use
care during removal to avoid damaging the sensor.

13. Remove the clevis pins securing the Transfix Load Arms to the chassis and
remove the Transfix Load Arms and the Media Release Blade Carriage
Assembly. (See the figure on page 8-28.)
14. Remove 3 left-handed screws (8500/8550) and washers from the right side of the
Drum Assembly. Note that one of the screws has no washer. The 8400 uses 3
right-handed screws.
15. Remove 3 screws and washers from the left side of the Drum Assembly.

Service Parts Disassembly 8-35

16. Remove the Drum Assembly from the chassis by lifting it straight up as shown in
the following figure.

Note
You will need to temporarily remove 3 screws of the media drive motor (PL
4.8) and pull the motor out of the way before you can lift the drum and
pulley from the chassis.

Yellow Left-Hand
Threaded Screws

No Washer

s8500-096

Caution
Never rest the drum on its pulley. Let the pulley hang over the edge of a
surface and place the drum on its feet.

Replacement Notes:
1. Gently seat the Drum Assembly into the chassis.

Caution
The Drum Thermal Sensor Cable is routed through the Exit Module. Use
care when reinstalling to avoid damaging the sensor.

Note
To help seat the drum properly, the following steps 2-6 provide an explicit
order of placement for installing the screws to secure the drum assembly to
the chassis.

8-36 Phaser 8400/8500/8550 Color Printer

 2. Align the screw holes in the left and right sides of the drum assembly to the holes
in the chassis sides.
3. Install one silver screw at the rear position of the left-side of the chassis to hold
the left side of the drum assembly and torque the screw to 25 in.-lbs.
4. Install the remaining two silver screws into the bottom and front chassis locations
to the left side of the drum assembly.
5. Install one yellow reverse-threaded screw at the rear position of the right-side
chassis to hold the right side of the drum assembly and torque to 25 in.-lbs.
6. Install the remaining two yellow reverse-threaded screws into the bottom
location (without a washer) and the front location (with a washer) on the right
side of the drum assembly.
7. Spread apart the chassis handles near the left and right labyrinth seals to ensure
the bearing is properly sealed.
8. Align the clevis on the Transfix Load Arms with the holes in the mounting ears
on the Drum. The Transfix Load Arms point in the opposite direction from the
Drum Thermistor. Ensure that the cam followers on the Transfix Load Arms are
under the Transfix Cams.
9. Insert the clevis pins through the clevis and the mounting ears on the drum (pins
are inserted from the outside). Ensure that the o-rings are mounted on the inside
end of each clevis pin.
10. Align the Exit Module to the chassis and route the Drum Thermistor cable
through the opening in the Exit Module that the other cables pass through. Seat
the Exit Module on the two front locating pins and then on the rear locating pins.
11. Insert and torque the four screws securing the Exit Module Assembly to
15 in.-lbs.
12. Apply a small quantity of Rheolube 768 grease (P/N 00679900) to the spring
hook’s groove of the Transfix Load Arms.

Note
Ensure that you lever the spring cam towards the center. Applying the
pressure in the wrong direction can damage the Transfix Load Module (see
the figure on page 8-27).

13. Insert a T-20 Torxbit through the right side slotted hole in the Transfix Load
Module, engage the hole on the back of the module, and lever the module’s
spring cam toward the center of the printer while connecting the spring hooks to
the Transfix Load Arms. Repeat for the other side.
14. Pull the lower end of the Y-Axis spring arm toward the front of the printer and
install the Y-Axis belt first on the motor pulley and then on the drum pulley. (It is
not necessary to align the belt on the drum pulley.) Ensure that the grooves of the
belt align in the grooves of the motor pulley and that the cross-ribs are away from
the pulleys.
15. Reposition the Media Drive Motor, insert the 3 screws, and torque the screws to
12 in.-lbs.
16. Connect the Media Drive Motor Fan and Media Drive Motor cables. Bend the
cable retainer as required to hold the fan cable.

Service Parts Disassembly 8-37

17. Connect the Drum Heater Cable to the Relay Board.
18. Connect the Drum Encoder Cable to the Power Control Left Cable.
19. Connect the Drum Thermal Sensor Cable to the I/O Board.

Caution
The Drum Thermal Sensor Cable is routed through the Exit Module. Use
care when reinstalling to avoid damaging the sensor.

20. Connect the Exit Module Cable to the I/O Board.

21. Ensure that the Drum Heater Cable and Drum Encoder Cable are dressed
correctly and secured by the retainer hook at the Process Gear Assembly.
22. Reinstall the Drum Fan Assembly and secure it with 3 screws. Torque the top
screw into the Labyrinth Seal to 20 in.-lbs. and the other two screws into the
chassis to 12 in.-lbs.
23. Pass the Media Release Blade Solenoid cable through the right side of the chassis
and seat the Lower Inner Duplex Guide on the four mounting pins on the chassis.
24. Install the Ink Loader Assembly (see page 8-8).
25. Reinstall all covers and doors.

8-38 Phaser 8400/8500/8550 Color Printer

Purge Pressure Pump
(PL 2.7)
1. Remove the left side cover (see "Left Side Cover" on page 8-7).
2. Disconnect the air hose from the Purge Pressure Pump.
3. Disconnect the wiring harness from the Purge Pressure Pump.
4. Remove three screws and remove the Purge Pressure Pump.

s8500-097

Service Parts Disassembly 8-39

Paper Path

Exit Module Assembly

(PL 3.15)
1. Remove the Exit Cover and both side covers (see page 8-7).
2. Remove the three screws securing the media drive motor, and let the motor hang.
3. Disconnect three connectors: two on the right (I/O Board J680 and J870) and one
on the left.

Caution
The Drum thermal and sensor cable (J870) passes through the Exit Module.
Do not damage this cable during removal. The cable must be re-routed
through the Exit Module during installation.

4. Remove the four screws holding the Exit Module Assembly to the printer chassis
and remove the Exit Module Assembly.

Note
You may need to remove the paper path motor to access the screw.

s8500-132

Replacement Note:
After installing the Exit Module, perform the Wiper Alignment (see page 6-2).
The printer may report error code 7,009.4x if the wiper assembly is misaligned.

8-40 Phaser 8400/8500/8550 Color Printer

Paper Guides

Inner Simplex Guide

(PL 3.1)
1. Open the printer Front Door to access the guide.
2. Using a small flatblade screwdriver, pry inward on one retainer to remove it from
the mounting post then remove the other retainer.
3. Slide the guide down and forward to remove.

Replacement Note:

Note
The fingers on the Inner Simplex Guide, go over the segmented roller. First
snap the left retainer into place, then the right.

Lower Inner Duplex Guide

(PL 3.2)
1. Open the Front Door of the printer.
2. Pull out on the tabs at the bottom of the guide and let the guide swing free.
3. Pry inward (toward the center of the printer) on the right upper retainer until it is
free of the mounting boss and remove the guide.

Lower Exit-Guide Assembly with Strip Flag

(PL 3.3)
1. Open Exit Door.
2. Lift upward on the center of the guide, then flex the left retainer inward to
remove it.
3. Remove the right retainer and remove the guide.

Outer Duplex Paper Guide With Sensors (Safety Interlocks)

(PL 3.4)
1. Remove the Control Panel (see page 8-6).
2. Remove 4 screws and remove the guide.

Service Parts Disassembly 8-41

Upper Duplex Guide with Solenoid
(PL 3.5)
1. Remove the Right Side Cover (see page 8-6).
2. Remove the Outer Duplex Paper Guide as specified in the preceding paragraph.
3. Disconnect the solenoid connector from the I/O board and extract the harness
from the right side frame.
4. Remove the Upper Duplex Guide from the printer.

Outer Duplex Paper Guide

Lower Inner Duplex Guide

Inner Simplex Guide

Lower Exit Guide Assembly

s8500-098

8-42 Phaser 8400/8500/8550 Color Printer

 Solenoid Lever

Upper Duplex Guide

Hole for
Solenoid Lever

s8500-099

Replacement Notes:

Note
Route the solenoid harness through the right side frame when replacing the
Upper Duplex Guide.

Note
Verify that the solenoid lever engages the hole in the Paper Release Guide.

Service Parts Disassembly 8-43

Take Away Roller
(PL 3.7)
1. Remove the left and right side covers from the printer (see page 8-7).
2. Remove the Media Drive Gearbox (see page 8-48).
3. Remove the Lower Simplex Guide (see page 8-41).
4. Remove the KL-clip from the right end of the shaft.
5. Remove the KL-clip and bushing from the left end of the shaft.
6. Move the Take Away Roller shaft to the left side of the printer to release it from
the right side frame, rotate the shaft forward, and remove it to the right.

Note
Pressure from the idler rollers makes it difficult to move the Take Away
Roller shaft to the right during removal.

Take Away Roller

KL-Clip
Bushing

s8500-100

8-44 Phaser 8400/8500/8550 Color Printer

Pick Assembly
(PL 3.10)
1. Remove Tray 2 from the printer.
2. Reach into the tray cavity and release the orange colored catch holding the Pick
Roller in place. The catch is located on the ceiling of the tray cavity about 1/4 of
the way across the unit from the right side and about 12.5 cm (5 inches) back.
When you pull forward on the catch, the roller will swing down.

s8500-101

s8500-102

3. Pull down to remove the roller.

Note
Replace the Retard Roller (see following figure) at the same time you
replace the Pick Assembly.

Replacement Note:

Note
Insert the replacement with the metal shaft at the top and toward the left, the
grey rollers should be facing you. Position the roller back about5 cm (2
inches) in the tray cavity. Push the pick assembly up into the chassis and
snap it into place. Then, rotate the Pick Assembly up and back to latch.

Service Parts Disassembly 8-45

 1
2

2
1

s8500-103

8-46 Phaser 8400/8500/8550 Color Printer

Media Tray Lift Motor
(PL 4.6)
1. Remove the Electronics Module (see page 8-55).
2. Remove Tray 2.
3. Disconnect the wiring harness from the Media Tray Lift Motor.
4. From the rear of the printer, inside the cavity, remove the push nut (this is a press
fit).
5. Remove the gear from the shaft.
6. Remove the two screws holding the Media Tray Lift Motor to the printer frame.
7. Remove the Media Tray Lift Motor from the outside of the printer.

Lift Motor Gear

Push Nut s8500-104

Replacement Note:

Note
Ensure that the two tabs of the bushing are seated in the chassis. Position the
push nut so the fingers on the inside of the nut are pointed up toward the end
of the shaft. Place a box wrench or socket wrench of the same size as the
outer ring of the push nut over the nut and press firmly to seat the nut on the
shaft.

Service Parts Disassembly 8-47

Motors, Gears, Solenoids, Clutches, and Fans

Media Drive Gearbox with Two Clutches and Solenoid

(PL 4.8)
Videos are available with instructions for replacing the Media Drive
Gearbox. Videos are located on the Phaser 8400/8500/8550 Product
Training CD-ROM. Select Service and then select Media Drive
Procedures).
1. Remove the Left side (page 8-7) and Exit cover (page 8-7).
2. Disconnect the fan, media path motor, deskew clutch, pick clutch, and Tray 1
pick solenoid wiring harnesses.
3. Remove the six screws securing the Media Drive Gearbox.
4. Remove the Media Drive Gearbox.
Media Drive Gearbox
Duplex Roller Shaft

Pick Clutch

Loosen Only
(Do Not Remove)
Pick Roller Shaft

s8500-105

8-48 Phaser 8400/8500/8550 Color Printer

Replacement Note:

Note
To replace the Media Drive Gearbox, first remove the paper tray. Rotate the
Pick Roller Shaft until the clutch seats. Then work upwards, rotating the
Take Away rollers and the Duplex Roller until all shafts seat properly.
Ensure that the Media Drive Gearbox is correctly positioned on the side
frame. Also, ensure that all rollers can rotate freely.

Tray 1 Pick Solenoid

(PL 4.10)
1. Remove the left side cover from the printer (see page 8-7).
2. Disconnect the solenoid cable.
3. Remove one screw from the solenoid, and remove the solenoid from the Media
Drive Gearbox.

Tray 1 Pick Solenoid s8500-106

Service Parts Disassembly 8-49

Preheater Lift Solenoid
(8500/8550 only)
(PL 4.13)
1. Open (do not remove) the Front Door (MPT) assembly (see page 8-4).
2. Remove the Control Panel and cover (see page 8-6).
3. Remove four screws, disconnect two connectors, and remove the Exit Module
(see page 8-40).
4. Remove the outer and upper duplex guides (see page 8-41). The pre-heater lift
solenoid is now visible on the top of the transfix load module.
5. Disconnect the three-wire cable that attaches the solenoid to the media-box
motor.
6. Remove the single screw holding the solenoid to the transfix load module and lift
out.

s8500-134

8-50 Phaser 8400/8500/8550 Color Printer

Process Drive Motor and Gearbox
(PL 4.9)
Videos are available with instructions for replacing the Process Drive
Motor and Gearbox. Videos are located on the Phaser 8400/8500/8550
Product Training CD-ROM. Select Service and then select Process
Drive Procedures).
1. Remove the right side cover (see page 8-6).
2. Disconnect the drum heater wiring harness from the Relay Board to get it out of
the way and free other wiring harnesses from the gearbox cable restraint.
3. If you will be installing new or re-installing this gearbox, pin the gears in position
to ensure correct alignment on replacement (see the figure and following text).

Process Drive Motor

and Gearbox

Holes in process
drive frame aligns
with holes in
gears

Hole in gear
aligns with
arrow on Hole in gear
frame aligns with
arrow on frame

s8500-107

Service Parts Disassembly 8-51

Examine the process gear drive train for the following:

■ The holes is the process drive frame must align with the holes in the gear.

■ The hole in the drum maintenance camshaft gear must align with the arrow on the
frame.

Caution
The hole in the transfix camshaft gear align with the hole on the frame.
Replacement gear boxes come with two pins to hold the gears in position.
Use either the pins that come with replacement gear boxes, or a paper clip,
bent into a U shape to hold the gears in their proper position during removal
and replacement.

1. Remove three screws and remove the Process Drive Motor and Gearbox.
2. Disconnect the wiring harness from the Process Drive Motor.

Replacement Notes:
Caution
If the Process Gearbox is not re-installed with the gears in the correctly
aligned and “pinned” positions, the printer will not function correctly and
could be damaged. Refer to the "Homing the Process Gear Drive Train" on
page 6-8.

Caution
Be careful of the wiring harness to the Process Drive Motor and other nearby
wiring. If the wires are pinched during reinstallation damage to the
electronics module will occur. Ensure that the harness is routed via the
cutout in the gearbox frame (see figure on page 8-51).

Caution
Before installing the Process Gearbox, use a slotted screwdriver to rotate the
DM Camshaft 360º clockwise to ensure that the head tilt system is in the
home position.

Caution
Seat the Process Drive Motor and Gearbox and seat all three screws before
torquing the screws to final tightness. Torquing the screws individually
before seating all components, can put undue strain on the mounting bosses.

Caution
When reinstalling the gearbox, the hole in the bottom mating gear should be
aligned with the arrow embossed on the ground plane. The hole in the upper
mating gear should be aligned with the adjacent hole in the frame (see figure
on preceding page). Remove pins from the new gearbox after installation.

Note
Ensure that the drum heater harness, Y-Axis encoder harness, and the drum
fan harness are replaced in the cable restraint on the gearbox.

8-52 Phaser 8400/8500/8550 Color Printer

X-Axis Motor Assembly
(PL 4.5)
1. Remove the Right Side Cover from the printer (see page 8-6).
2. Disconnect the wiring harness.
3. Remove four screws securing the motor to the chassis and remove the motor.

X-Axis Motor

Side Rail s8500-108

Replacement Note:
Note
When reinstalling the X-Axis motor, ensure that the fork, extending out from the
side of the cone nut on the motor shaft, is engaged with the side rail.

Service Parts Disassembly 8-53

Head Tilt Compound Gear
(PL 4.7)
1. Remove the printhead Assembly (see page 8-12).
2. At the left side of the Printer, remove the KL-clip as shown in the figure below.
3. Remove the waste tray frame, without disconnecting the sensor wiring harness.
4. Reach in to the waste tray cavity and remove the Head Tilt Compound Gear.

Remove KL-Clip

Head Tilt Compound Gear

s8500-109

Replacement Notes:

Note
On reassembly, the leaf spring on the back side of the chassis must be behind
the gear to engage.

Note
On reassembly, lubricate the curved (cam) surfaces of the gear using a small
quantity of Rheolube 768 grease (P/N 00679900).

8-54 Phaser 8400/8500/8550 Color Printer

Electronics

Electronics Module
(PL 5.1)
Videos are available with instructions for replacing the Electronics
Module. Videos are located on the Phaser 8400/8500/8550 Product
Training CD-ROM. Select Service and then select Replacement
Videos).

Caution
Touch the back of the Electronics Module before starting this procedure to
discharge any electrostatic charge present on the case. Also, do not
completely remove EMI tape, if added to a connector.

1. Disconnect the power cord and all cables to the Electronics Module. On the
8500/8550 you need to peel back the EMI tape from the printhead data cable.
2. Remove the Ink Loader Assembly and Door (see page 8-8).
3. Remove five screws from the back of the Electronics Module and two screws
from inside the printer chassis.
4. Remove the Electronics Module.

EMI Tape (8500/8550)

s8500-110

Replacement Note:

Note
When replacing the electronics module, transfer the Configuration Card,
NVRAM, SODIMM RAM, and hard drive (if installed) to the new module.

Service Parts Disassembly 8-55

Wave Amp Board
(PL 5.3)
1. Remove Electronics module (see page 8-55).

Note
Do not fully remove EMI tape, if included with any connector.

2. Remove printhead (see page 8-12).

3. Remove three screws (see illustration below).

Caution
Route the ribbon cables carefully through the slots.

4. Remove the Wave Amp Board through the back of the printer.

s8500-111

Replacement Note:
Caution
Ensure that the ribbon cables are fully and squarely inserted into the flex
connector on the Wave Amp and printhead. If the cables are inserted
incorrectly, they can damage the Wave Amp Board. Route the ribbon cables
carefully through the slots. Ensure that the T-shaped strain relief on the cable
is nearest the Wave Amp on installation.

8-56 Phaser 8400/8500/8550 Color Printer

I/O Board
(PL 5.4)
1. Remove the right side cover (see page 8-6).
2. Disconnect the wires to the I/O Board.
3. Remove the two screws attaching the I/O Board to the printer.
4. Remove the I/O Board.

I/O Board
Ground Tab

s8500-112

Replacement Note:

Note
Ensure the corner of the board is behind the ground tab on reassembly.

Service Parts Disassembly 8-57

Drum Heater Relay Board
(PL 5.5)

Warning
This is an AC board, shut off power to the printer and disconnect the power
cord before starting this procedure.

1. Remove the right side cover (see page 8-6).

2. Disconnect the three wires to the Drum Heater Relay Board.
3. Remove the screw securing the Drum Heater Relay Board to the printer.
4. Remove the Drum Heater Relay Board.

Drum Heater
Relay Board

s8500-113

Replacement Note:

Warning
Ensure that no wires are routed behind the Drum Heater Relay Board during
reinstallation. Some of these wires carry AC line voltage and a short could
result in AC being shorted to accessible locations.

8-58 Phaser 8400/8500/8550 Color Printer

NVRAM Replacement
(PL 5.8)
1. Remove the back cover from the Electronics Module.

Caution
Some semiconductor components, such as the NVRAM chip, are vulnerable
to damage by Electrostatic Discharge (ESD). Review the "Electrostatic
Discharge (ESD) Precautions" on page 1-v before continuing with this
procedure.

Note
Observe the orientation of the NVRAM chip before removing it and use this
as a guide for proper replacement.

2. Remove the old NVRAM chip from it’s socket in the Electronics Module.

NVRAM Chip

s8500-114

3. Insert the new NVRAM chip into the socket. Ensure that the notch on the chip is
on the left side.
4. Download the snippet titled “setsn.ps” from infoSMART.
5. Edit the snippet to include the printer serial number, using a text editor.
6. Download the edited file to the printer using an FTP program.

Service Parts Disassembly 8-59

DIMM Replacement
(PL 5.7)
1. Remove the back cover from the Electronics Module.
2. Remove the two finger screws of the Electronics Module and swing the door
down to the full open position.

Caution
Some semiconductor components, such as the DIMM chips, are vulnerable
to damage by Electrostatic Discharge (ESD). Review the "Electrostatic
Discharge (ESD) Precautions" on page 1-v before continuing with this
procedure.

Note
Observe the orientation of the DIMM (Dual-in-Line Memory Module) chips
before removing them and use this as a guide for proper replacement. Notice
that the DIMM boards are inverted to each other.

3. Pull the connector release tabs away from the DIMM’s to release (see
illustration). The Phaser 8400 includes a clip that secures the Dimms in place.
For the 8500/8550 DIMM’s, the top DIMM swings down and the bottom DIMM
swings up in the removal position, while they clip in place in the flat position.
4. Remove the old DIMM chips from their sockets in the Electronics Module.

8400

8500/8500

s8500-115

5. Insert the new DIMM chips into the sockets.

6. Swing the DIMM chips to their secure position against the electronics module
and snap them into their respective connectors.

8-60 Phaser 8400/8500/8550 Color Printer

Hard Drive Replacement
(PL 5.2)
1. Remove the back cover from the Electronics Module.

Caution
Some semiconductor components, such as the NVRAM chip, are vulnerable
to damage by Electrostatic Discharge (ESD). Review the “Electrostatic
Discharge (ESD) Precautions” on page v before continuing with this
procedure.

2. Disconnect the two connectors from inside the Electronics Module.

3. Pull out and replace the entire unit, including chassis holder, hard drive, and
board.

2 1
3
3
3

s8500-116

4. Reattach the two connectors to the new hard drive unit.

5. Close the new unit with the hand screws.

Service Parts Disassembly 8-61

Parts Lists
In this chapter...
■ Serial Number Format
■ Using the Parts List
■ Xerox Supplies

Section
9
Serial Number Format
Changes to Xerox products are made to accommodate improved components as they
become available. It is important when ordering parts to include the following
information:
■ Component's part number
■ Product type or model number
■ Serial number of the printer
Serial numbering. Particular fields in the serial number indicate the modification level
of the printer, the date of its manufacture and the sequence number of the printer
produced on that day.

The serial number is coded as follows:

■ The text “S/N” followed by the serial number in the barcode.
■ The barcode does not include a field identifier.
■ The nine digit serial number is based on the following format:
PPPRSSSSS.

PPP = Three digit alphanumeric product code

Product Model Product Code

8400 B, BD, N, DP, DX RPC

8400 DPF TMV

8500 N, DN WYN

8550 DP, CT, DX WYP

8550 DPF L91

R - Single digit numeric revision digit. To be rolled when a major product change
occurs. Initiated with a change request.
SSSSS - Five digit numeric serial number.

Serial Number Example:

RPC453072:
4 = Revision level
53072 = Serial number

9-2 Phaser 8400/8500/8550 Color Printer

Using the Parts List
1. No.: The callout number from the exploded part diagram.
2. Part Number: The material part number used to order specific parts.
3. Qty: This number represents the parts per printer, not the number of parts
supplied in the actual part order.
4. Name/Description: Details the name of the part to be ordered and the number of
parts supplied per order.
5. Parts identified throughout this manual are referenced PL#.#.#. For example,
PL3.1.10 means the part is item 10 of Parts List 3.1.
6. A black triangle preceding a number followed by a parenthetical statement in an
illustrated parts list means the item is a parent assembly, made up of the
individual parts called out in parentheses.
7. The notation “with X~Y” following a part name indicates an assembly that is
made up of components X through Y. For example, “1 (with 2~4)” means part 1
consists of part 2, part 3, and part 4.
8. An asterisk (*) following a part name indicates the page contains a note about
this part.
9. The notation (NS) next to a part indicates that particular part is not spared, but
contained in a kit or major assembly.
10. The notation “J1<>J2 and P2” is attached to a wire harness. It indicates that
connector Jack 1 is attached to one end of the wire harness and connector J2 is
attached to the other end that is plugged into P2.

Note
Only parts showing part numbers are available for support. Parts not showing
part numbers are available on the parent assembly.

Legend:

Identifier Meaning

C C-ring

E E-ring

KL KL-clip

S Screw

Parts Lists 9-3

Covers

6
7

5
8

9
13

12

2
3

2
4

3 11
4
10
14
1

s8500-117

9-4 Phaser 8400/8500/8550 Color Printer

Parts List 1.0 Covers

No. Name/Description Qty Part Number

1 Front Door (MPT) Assembly 1 200467880 (8400)

802K93580 (8500/8550)

2 Front Door Stay Retainer Clip 2 131714380

3 Front Door Stay with Spring 2 386740780

4 Hinge Pins, Front Door 2 131713880

5 Control Panel Cover 1 200467380 (8400)

802E93850 (8500/8550)

6 Control Panel with Bezel 1 657012880 (8400)

802K93650 (8500/8550)

7 Exit Cover Assembly 1 200469380 (8400)

Exit Cover with Badge 802K93590 (8500)
802K88420 (8550)

8 Ink Loader Door (part of PL 2.1) 1 200469880 (8400)

133K25031 (8500/8550)

9 Left Side Cover 1 200467680 (8400)

802K93660 (8500/8550)

10 Right Side Cover Assembly with Doors 1 200467580 (8400)

802K93570 (8500/8550)

11 Drum Maintenance Door (Side) 1 200469480 (8400)

802E93870 (8500/8550)

12 I/O Access Door 1 200468480 (8400)

802E93860 (8500/8550)

13 Waste Tray Cover 1 200466780

14 Waste Tray 1 109R00736

Parts Lists 9-5

Imaging

3
4
5

19

6
18 20
7
12 21

13
14 9

15
16

17
11
10

18

9-6 Phaser 8400/8500/8550 Color Printer

Parts List 2.0 Imaging

No. Name/Description Qty Part Number

1 Ink Loader Assembly and Door 1 200469880 (8400)

133K25031 (8500/8550)
133K25660 (Metered PagePack
8550)

2 Printhead Assembly 1 650430300 (8400)

046K00510 (8500/8550)

3 Drum Assembly, includes Encoder 1 105115080 (8400)

020K14790 (8500/8550)

4 Belt, Y-Axis Drum 1 214498780 (8400)

023E30670 (8500/8550)

5 Printhead Wiper (for wide-style belts) 1 367053480 (8400, 8500/8550)

6 Belt, Wiper Drive (wide-style) 1 214501280 (8400, 8500/8550)

no narrow belt, use wide wiper&belt

7 Purge Pressure Pump 1 604K31120

8 Left Printhead Restraint 1 343167280

9 Right Printhead Restraint 1 343167180

10 Transfix Camshaft Assembly 1 384187480 (8400)

008K02160 (8500/8550)

11 Drum Maintenance Camshaft Assembly 1 401100380 (8400)

020K14800 (8500/8550)

12 Stripper Carriage Assembly 1 386735280 (8400)

041K06500 (8500/8550)

13 Transfix Roller 1 401102780 (8400)

022E32290 (8500/8550)

14 Y-Axis Tension Spring 1 214499680

15 Transfix Load Arm Module Assembly 1 386739380 (8400)

137E14030 (8500/8550)

16 Drum Maintenance Pivot Plate Assembly 1 367053181

17 Preheater and Deskew Assembly 1 119641980 (8400)

126K23150 (8500/8550)

18 Transfix Arm Assembly 1 401101280 (8400)

059K50010 (8500/8550)

19 X-Axis Bias Spring Hook 1 214503280

20 X-Axis Roll Adjuster Spring 1 214503180

21 Printhead X-Axis Bias Spring 1 214503080

Parts Lists 9-7

Paper Path

4
13

8 6
7
2
3
1

10
12
11

s8500-119

9-8 Phaser 8400/8500/8550 Color Printer

Parts List 3.0 Paper Path

No. Name/Description Qty Part Number

1 Inner Simplex Guide 1 351111480 (8400)

032E29480 (8500/8550)

2 Lower Inner Duplex Guide 1 038K16870

3 Lower Exit Guide Assembly with Strip Flag 1 038K16880

4 Outer Duplex Paper Guide with Sensors (Safety 1 351113680

Interlocks)

5 Upper Duplex Paper Guide with Solenoid 1 351113280 (8400)

032E29490 (8500/8550)

6 Exit Roller 1 401091980

7 Take Away Roller 1 401094780

8 Duplex Roller 1 401091880

9 Separator Pad Kit 1 650429300 (8400)

604K31140 (8500/8550)

10 Pick Assembly and Retard Roller Kit 1 650429200 (8400)

604K31130 (8500/8550)

11 Main Tray (Tray 2) 1 650433200 (8400)

050E23080 (8500/8550)

12 525-Sheet Feeder and Tray 1 650433100

13 Exit Module Assembly 1 441223980 (8400)

133K25020 (8500/8550)

Parts Lists 9-9

Motors, Gears, Solenoids, Clutches, and Fans

4
5
9

10
3 7*

2 11

12

14 13
s8500-120

9-10 Phaser 8400/8500/8550 Color Printer

Parts List 4.0 Motors, Gears, Solenoids, Clutches, and Fans

No. Name/Description Qty Part Number

1 Pre-heater Lift Solenoid 1 121K44430 (8500/8550)

2 Motor, Y-Axis Drive 1 147101780

3 Pick Solenoid, Tray 1 1 119640880

4 Head Tilt Solenoid 1 121K44480 (8500/8550)

5 Gearbox, Media Drive with 2 Clutches, Solenoid 1 401098480 (8400)

807E16050 (8500/8550)

6 Tray Lift Motor Kit and Gear (plus item 10) 1 650429500

7 Paper Path Cooling fan 1 119650580 (8400)

No longer orderable (refer to
service bulletin 655).

8 Electronics Module System Fan 1 119642680 (8400)

133K25010 (8500/8550)

9 Compound Gear, Head Tilt 1 401097880

10 Tray Lift Motor Kit and Gear (plus item 6) 1 650429500

11 Electric Clutch, Wiper 1 401096180

12 X-Axis Motor Assembly 1 650429400

13 Drum Cooling Fan 1 119641780 (8400)

127E15090 (8500/8550)

14 Gearbox and Motor, Process Drive 1 401100080 (8400)

127K53240 (8500/8550)

Parts Lists 9-11

Circuit Boards

6
7
5
3
1
2
8
4

10
11

12

13

18
17 14

15
16
s8500-121

9-12 Phaser 8400/8500/8550 Color Printer

Parts List 5.0 Circuit Boards and Cables

No. Name/Description Qty Part Number

1 Cable, Y-Axis Motor Ground 1 117E28740

2 Wiring Harness, Left Side Power Control 1 174449480 (8400)

117E28720 (8500/8550)

3 Cable, Wave Amp Signal 1 174446580 (8400)

117E28680 (8500/8550)

4 Wave Amp Assembly 1 671522380 (8400)

960K21180 (8500/8550)

5 Electronics Module (no RAM, NVRAM, or 1 119649580 (8400)

Configuration Card) 137E14020 (8500/8550)

6 Cable, Printhead Interface 1 174448580

7 Hard Drive Assembly 1 097S03172 (8400)

121K44411 (8500/8550)
Hard Drive with Japanese Fonts 1 097S03173 (8400)
1 121K44420 (8500/8550)

8 128 MB SDRAM 1 156483700 (8400)

256 MB SDRAM 156466300 (8400)
128 MB SDRAM 856000200 (8500)
256 MB SDRAM 856000300 (8500/8550)
512 MB SDRAM 856000400 (8550)

9 8-pin NVRAM 1 156476800

10 Configuration Card-B, Prog. 1 650431200 (8400)

Configuration Card-BD, Prog. 1 650431300 (8400)
Configuration Card-N, Prog. 1 650431400 (8400)
Configuration Card-DP, Prog. 1 650431500 (8400)
Configuration Card-DX, Prog. 1 650431600 (8400)
Configuration Card-N, Prog. 069E00360 (8500)
Configuration Card-DN, Prog. 1 069E00370 (8500)
Configuration Card-DP, DT and DX, prog. 1 069E00380 (8550)

11 Cable, Flex, Wave Amp Drive 1 174448680 (8400)

117E28670 (8500/8550)

12 Cable, Right Side Power Control 1 174446680

13 I/O Board 1 671529100 (8400)

960K22330 (8550/8550)

14 Cable, Combined Right (Ink Loader Data, 1 174451180 (8400)

Preheater AC) 117E28730 (8500/8550)

15 Cable, I/O Board Data 1 174447480

16 Cable, Right Umbilical 1 174448180

17 Drum Heater Relay Board 1 650431700

18 Cable, Front Door 1 174447880

Parts Lists 9-13

Sensors and Flags (Actuators)

1
4

2 7

s8500-122

9-14 Phaser 8400/8500/8550 Color Printer

Parts List 6.0 Sensors and Flags (Actuators)

No. Name/Description Qty Part Number

1 Drum Temperature Sensor Assembly 1 119643080

2 Optical Sensor (Generic Snap-In) 1 119640580

3 Safety Interlock Switch (Mech) 1 119645580

4 Exit Module Sensor Assembly 1 119648180

5 Paper Present Flag 1 386731280

6 Exit Flag 1 386732680

7 Sensor Assembly, Paper Tray 1 441223780

8 Waste Tray Sensor 1 119648780

Parts Lists 9-15

Xerox Supplies
Kits

Description Part Number

Mechanical Kit (Hardware) 604K31780

■ Nut Plate - 2 ea.
■ 6 mm press nut - 2 ea.
■ #8 SAE washer - 5 ea.
■ Thumbscrews - 2 ea.
■ M4 x 12 delta pt/ hexhead - 5 ea.
■ M4 x 32, partial thread flanged
hex - 5 ea.
■ M4 x 32, partial thread flanged
hex, left-hand thread, yellow - 5
ea.
■ M4 x 12, taptite flanged - 5 ea.
■ ASMO clip, lift motor - 2 ea.
■ E-ring, bent M6 5 mm - 5 ea.
■ Bushing 6 mm - 2 ea.
■ Cable Restraint - 2 ea.
■ Left-hand drum screw (yellow - 2
ea.)
■ Frame Replace Screw (red blue
tint - 5 ea.)

Repackaging Kit 065062800 (8400)

659K22810 (8500/8550)

Cleaning Kit 016184500

Power Cords

Description Part Number

Cable Assembly, 3,18 AWG, 115 V, 98, 0 L 161006600

Cable Power EURO 220 V, 99 L 161006609

Cable Power U.K. 240 V, 96 L 161006610

Cable Power AUST 240 V, 96 L 161006611

Cable Assembly SWISS 220/240 V, 50 Hz 161015400

Cable Assembly PWR. DANISH, 250 V 161024000

Cable Assy PWR, CHINESE 161030400

Cable Power, 240 V, ARGENTINA 161030700

9-16 Phaser 8400/8500/8550 Color Printer

Upgrade Kits and Options

Description Part Number

Hard Drive Upgrade Kit 097S03172 (8400)

121K44410 (8500/8550)

Hard Drive Upgrade with Japanese Fonts 097S03173 (8400)

121K44420 (8500/8550)

Memory (8400)
128 MB, 16M x 64, PC133; Memory DIMM ZMD128
256 MB, 32M x 64, PC133; Memory DIMM ZMD256

Memory (8500)
128 MB, SDRAM 097S03380
256 MB, SDRAM 097S03381

Memory (8550)
256 MB, SDRAM 097S03381
512 MB, SDRAM 097S03382

525-Sheet Feeder with Tray (8400/8500/ 097S03174

8550)

Recommended Tools

Description Part Number

Torque Screwdriver 003082700

T20 Screwdriver Tip 003086600

Mechanical Parts Kit 650429700

Flashlight

Grease 006799700

Consumables and Routine Maintenance Items

Description Part Number

Standard-Capacity Maintenance Kit 108R00602 (8400 series)

108R00675 (8500 series)

Extended-Capacity Maintenance Kit 108R00603 (8400 series)

108R00676 (8550 only)

Parts Lists 9-17

Consumables and Routine Maintenance Items

Description Part Number

Genuine Xerox Solid Ink Black (3 sticks) 108R00604 (8400 series)

108R00668 (8500 series)
108R00706 (8550 Metered
PagePack - 6 sticks)

Genuine Xerox Solid Ink Cyan (3 sticks) 108R00605 (8400 series)

108R00669 (8500 series)
108R00707 (8550 Metered
PagePack - 6 sticks)

Genuine Xerox Solid Ink Magenta (3 sticks) 108R00606 (8400 series)

108R00670 (8500 series)
108R00708 (8550 Metered
PagePack - 6 sticks)

Genuine Xerox Solid Ink Yellow (3 sticks) 108R00607 (8400 series)

108R00671 (8500 series)
108R00709 (8550 Metered
PagePack - 6 sticks)

Genuine Xerox Solid Ink Black (6 sticks) 108R00608 (8400 series)

108R00672 (8500 series)

Rainbow Pack (1 stick) 108R00612 (8400 series)

Genuine Xerox Solid Ink Cyan (1 stick) 108R00687 (8500/8550 series)

Genuine Xerox Solid Ink Magenta (1 stick) 108R00688 (8500/8550 series)

Genuine Xerox Solid Ink Yellow (1 stick) 108R00689 (8500/8550 series)

Genuine Xerox Solid Ink Black (1 stick) 108R00690 (8500/8550 series)

Software and Documentation

Description 8400 8500/8550

Setup Guide (poster) 001153600 001167300

Quick Reference Guide 71086500 0011167400

World Kit 061449300 650K24290

Printer Installer and Utilities CD-ROM 063344900 N/A

User Documentation CD-ROM 063345000 N/A

Software and Documentation CD-ROM N/A 063347500

8400/8500/8550 Service Manual 721P58550 (8400/8500/8550)

9-18 Phaser 8400/8500/8550 Color Printer

Phaser Color Printing Media

Description Part Number

Phaser Premium Color Printing Paper, 016136800

24 lb. Letter, 500 Sheets

Phaser Premium Color Printing Paper, 016136900

24 lb. A4, 500 Sheets

Phaser Premium Cover Paper, Letter, 016182300

100 Sheets

Phaser Premium Cover Paper, A4, 016182400

100 Sheets

Phaser Professional Solid Ink 103R01039

Transparency, Letter, 50 Sheets

Phaser Professional Solid Ink 103R01040

Transparency, A4, 50 Sheets

Phaser Professional Solid Ink Business 103R01041

Cards, Letter,10/sheet, 25 sheets

Phaser Professional Solid Ink Business 103R01042

Cards, A4,10/sheet, 25 Sheets

Phaser Color Printing Labels, Letter, 30/ 016181200

Sheet, 100 Sheets

Phaser Color Printing Labels, Letter, 6/ 016181300

Sheet, 100 Sheets

Phaser Color Printing Labels, A4, 14/Sheet, 016181400

100 Sheets

Phaser Color Printing Labels, A4, 8/Sheet, 016181500

100 Sheets

Phaser Premium Postcards, Letter, 4/Sheet, 103R01016

100 Sheets

Phaser Premium Postcards, A4, 4/Sheet, 103R01017

100 Sheets

Phaser Trifold Brochures, Letter, 103R01018

150 Sheets

Phaser Trifold Brochures, A4, 150 Sheets 103R01019

Phaser Weatherproof Paper, Letter, 103R01020

150 Sheets

Phaser Weatherproof Paper, 103R01021

A4,150 Sheets

Parts Lists 9-19

Phaser Color Printing Media (Continued)

Description Part Number

Supplies Startup Kit, Standard Size Media 097S03180

Supplies Startup Kit, Metric Size Media 097S03181

9-20 Phaser 8400/8500/8550 Color Printer

Wiring Diagrams
In this chapter...
■ Main Wiring Diagram
■ Right-Side Wiring Diagram
■ Left-Side Wiring Diagram
■ Inside Front Wiring Diagram
■ Inside Top Wiring Diagram
■ Inside Top - Printhead Wiring Diagram

Section
10
Main Wiring Diagram

Mode Switch

10/100T
Parallel
USB
Printhead Driver
ECB Electronics Module
JET0 +/-
JET1 +/- 40 connector
J200 J600 J400 JR810 J930
JET2 +/-
CLK +/- 4
ADCTX +/- J180
26
J130 Main Processor IDE
80
J580
Hard Drive J390
ADCRX +/- J860 ECB
+/-12 V regulated ECB
+3.3 V 2.5 Hard Drive
Gnd (9)
Spares (Vss & Vpp)
Vss Vpp
14
J210 (8400 Only) J240 6
2 Purge pump
Printhead tilt solenoid
30 30
J630 (8400 Only) J670 2 2 34
Main tray elevator plate motor Main Fan
Wave Amp ECB
2
VssD Main tray pick clutch
VppD 14 Media path
J800 3 motor 7
Gnd sense MPT solenoid
wave amp enable with encoder
+/-50 V 2
+/-12 V unregulated Deskew clutch
M. path motor fan
Gnd (6) (early 8400 only)
8, HCF connector
2
Tray 3 HCF Preheater Lift 3
8
Solenoid
3
Paper height opto J400 ((8500/8550)
Main ECB 2
3 11
Pick sense opto J120 Drum temp thermistor

3 2
Paper out sense opto HCF_RD Strip solenoid
HCF_TD
2 HCF_CLK 2
Pick clutch DMU life (i Button)
+50 V
+ +3.3 V
J380 3
Transport motor Gnd (3) Strip sense opto
– J980

3 8
Media Tray Exit/bin full sense opto
6 generates:
sense ECB J1 J160 24 V PWM 2
Heat maintenance clutch
Width sense (3) switch J820
Length sense (2) switch 10
Media Tray 6
2
Elevator plate motor sense ECB J1
8 Width sense (3) switch
Length sense (2) switch
Tray 4 HCF s8500-123

10-2 Phaser 8400/8500/8550 Color Printer

Main Wiring Diagram (Continued)
Printhead
AC Resv. heaters (2)
AC Jetstack heaters (2)

110/220

Connectors
LINE

Auxilary
Drum Heater
Series/parallel heater
35
J620 J480 30 connector
JDC1 3
Power Control 4 Power J3AC 35
4
J820 ECB X- axis motor
Supply

White
Black
7
ECB

Red
2
+/-50 V Drum fan J2AC
+/-12 V unreg AC
14 +3.3 V generates: 3
J790
16 4 Y axis pos encoder +/-50 V
generates J400 ECB +/-15 V unreg J3
+/- 12 V reg. (Right +3.3 V 4 2 2
Side) J2
+5 V J4AC Relay ECB J1
34 J1AC
J390 (Left Side) 7 Process motor
5 4 2
with encoder
Printer ambient
temperature 2
2 J0720 Paper preheater
J280 Y- axis motor

J800 (Right Side)

Pre-heat
ECB J0670 2
Serial 10
Inkload ECB J2 Preheat temp therm
J1 Deskew entry
Data Heaters (4) sense opto
Bus Ink out opto
3
14 Ink low opto J0660 Preheat sense opto
Door open opto J860
2 J840 J910
J870 Thermistor (4)
5
2
J250
I/O ECB 3
2
J860
Main tray paper height opto Control Panel 2
J400
10 3 ECB J190 Top door sense switch
Main tray paper opto
generates:
2
+5 V J110 Front door sense switch
3
8 +50 V Waste tray opto LCD Display
J680 +3.3 V
J600
3
J110 Process home (optional) 10
10 NOTE:
J220
The numbers shown at the circuit board
perimeters are for the actual connectors.
6
J600 J610
5 MPT ECB Some have extra n.c. pins added to prevent
misplugging errors.
Width sense var. resistor
Media present sense opto
I/O color coding
NOTE: Black = input
Thermal fuse for drum is located Magenta = output
on Pre-heated ECB
Red = temp
s8500-124

Wiring Diagrams 10-3

Right-Side Wiring Diagram
The arrows indicate which connectors you should look at for the Pest codes. The Pest
codes are displayed on the Control Panel.

Wiring Harness Pass-Through J680 13067.4x

J250 37020.4x Strip Solenoid
J910 13387.4
J400 Drum Heater
37016.4x
J110 Waste Tray HM Clutch
Wiring Harness
Pass-Through
Ground Clip
J870 13067.4x

J600 Add Paper Tray J860 Maintenance

Kit Missing

J840 Dead
Power
J610 No Handfeed

37006.4x
Drum Heater
(Pre-heater) Ground Clip
Drum AC is
routed thru
pre-heater prior to
relay board and drum
5002.42 37014.4x Drum Fan s8500-125

10-4 Phaser 8400/8500/8550 Color Printer

Right-Side Wiring Diagram (Continued)
The arrows indicate which connectors you should look at for the Pest codes. The Pest
codes are displayed on the Control Panel.

Routes to Top of Channel

13387.4x J4AC 37006.4x

J800 Dead
Power

J400 37027.4x

Signal Cable
37027.4x X-Motor Ribbon Cable (Routed in (Routed on
Middle of Channel) Bottom of Channel)
s8500-126

Wiring Diagrams 10-5

Left-Side Wiring Diagram
The arrows indicate which connectors you should look at for the Pest codes. The Pest
codes are displayed on the Control Panel.

37023.4x Purge Valve

37022.4x
Purge Motor

J280 37032.4x
Y-Motor

J790 37062.4x
Head VSS

J390 37034.4x MP Motor 37021.4x MT Elevator

37013.4x Electric Fan Channel (Connected to
Ground Strap)
s8500-127

10-6 Phaser 8400/8500/8550 Color Printer

Left-Side Wiring Diagram (Continued)
The arrows indicate which connectors you should look at for the Pest codes. The Pest
codes are displayed on the Control Panel.

37034.3x MP Motor

37015.4x MP Fan (8400 Only)

370xx.4x Preheater
Lift Solenoid (8500/8550 Only)

37017.4x Deskew Clutch

Ground Clip
37018.4x Pick Clutch

37019.4x Pick Solenoid s8500-128

Wiring Diagrams 10-7

Inside Front Wiring Diagram
The arrows indicate which connectors you should look at for the Pest codes. The Pest
codes are displayed on the Control Panel.

37036.4x Process Motor

37008.4x Preheat Power
(AC Connector)

Paper Jam Load Paper

(Open Front Cover) J860 13131.41 Sensor Flag
s8500-129

10-8 Phaser 8400/8500/8550 Color Printer

Inside Top Wiring Diagram
The arrows indicate which connectors you should look at for the Pest codes. The Pest
codes are displayed on the Control Panel.

8400

37010.4x
Ink 1 Heater
J2AC 37002.4x J1AC 37009.4x
JSL Heater (Ink Load Power)

J130 34062.4x (Data Cable)

8500/8550

37010.4x
Ink 1 Heater

J2AC 37002.4x J1AC 37009.4x

JSL Heater (Ink Load Power)

J130 34062.4x (Data Cable) s8500-130

Wiring Diagrams 10-9

Inside Top - Printhead Wiring Diagram
The arrows indicate which connectors you should look at for the Pest codes. The Pest
codes are displayed on the Control Panel.

Cable Restraint
Out of Ink J180 32064.4x

(8400 Only)
J140 37063.4x Head VPP

Heater Cable s8500-131

10-10 Phaser 8400/8500/8550 Color Printer

Appendix
Contents...
■ Menu Map (8400)
■ Menu Map (8500/8550)
■ Paper Weight Equivalence Table
■ On-site Printhead Troubleshooting Checklist (8400)

Appendix
A
Menu Map (8400)

Main Menu: READY TO PRINT. Front Panel Buttons: Up Arrow

Information OK
Walk-UpTM Features Cancel
Printer Setup
Troubleshooting Back Information
Shut Down
Down Arrow

= prints an information page.

Model Help Guide

Printer Name Configuration Page
Print Server* Paper Tips Page
Information
IP Address* Connection Setup Page
Serial # Moving Guide
Menu Map
Activation Date Startup Page
Printer Identification Usage Profile
PostScript Font List
Information Pages PCL Font List

Sample Pages

Supplies Info Maintenance Kit Life

Graphics Demonstration
Total Print Count
Office Demonstration
2-Sided Demonstration**
Print Mode Demonstration
Walk-UpTM Features* CMYK Sampler Pages
RGB Sampler Pages
Secure Print Jobs*****

Proof Print Jobs*****

Saved Print Jobs*****

Walk-Up PrintingTM

Select for Installation

TCP/IP Setup TCP/IP

NetWare Setup DHCP/BOOTP
Printer Setup
Ethernet Speed AutoIP
EtherTalk TCP/IP Address
Configuration Page Connection Setup Page
TCP/IP Network Mask
Network Setup*
Connection Setup TCP/IP Gateway
Parallel Setup Parallel Port
Port 9100
USB Setup Wait Timeout
LPR
Reset Connection Setup Page Description Language
IPP
Job Pipelining*
SLP
SSDP
USB Port CentreWare IS
Wait Timeout
Requires: Page Description Language NetWare
* Network Configuration Job Pipelining* IPX Frame Type
** Duplex Configuration
*** Optional Lower Tray(s)
**** Hard Drive Page 1 of 2
***** 8400DX only with stored jobs present

A-2 Phaser 8400/8500/8550 Color Printer

 Paper Source
2-Sided Printing**
Tray 1 Setup
PostScript Error Info Font Number
Tray 2 Paper Type
Print-Quality Mode Pitch
Tray 3 Paper Type***
TekColor Correction Point Size
Printer Setup Tray 4 Paper Type***
Image Smoothing Symbol Set
(continued) Load Paper Timeout
Reset PostScript Setup Orientation
Cleaning Page Source
Form Length
Paper Handling Setup Reset Paper Handling Setup
Line Termination
PostScript Setup Draft Mode
Reset PCL Setup
PCL Setup

Front Panel Setup Front Panel Language

Front Panel Brightness
Printer Controls Startup Page
Front Panel Contrast
Power Saver Timeout
Accessible Front Panel
Date and Time
Reset Front Panel Setup
Intelligent Ready
Metric Defaults
Reset Printer Controls

Troubleshooting

Help Guide Paper Tips Page Troubleshooting Print Quality

Online Jam Prevention Guide Page
Paper Jams Paper Path Test Eliminate Light Stripes
Remove Print Smears
Print Quality Problems

Network Log Pages* NetWare Start Log

NetWare Runtime Log
Service Tools Printer Status Page
TCP/IP Start Log
Engine Error History
TCP/IP Runtime Log
Jam History
AppleTalk Start Log
Diagnostics History
AppleTalk Runtime Log
Enter Diagnostic Mode
Service Usage Profile
Email Service Report*
Reset NVRAM

Shutdown

Power Saver (Recommended)

Restart Printer

Power Down To minimize ink usage, leave the printer on.

Requires:
* Network Configuration
** Duplex Configuration
*** Optional Lower Tray(s)
**** 8400DX only with stored jobs present Page 2 of 2

Service Manual A-3

Menu Map (8500/8550)

Main Menu: READY TO PRINT. Front Panel Buttons: Up Arrow

Information OK
Walk-UpTM Features Cancel
Printer Setup
Troubleshooting Back Information
Shut Down
Down Arrow

= prints an information page.

Model Help Guide

Printer Name Configuration Page
Print Server* Paper Tips Page
Information
IP Address* Connection Setup Page
Serial # Moving Guide
Menu Map
Activation Date Startup Page
Printer Identification Usage Profile
PostScript Font List
Information Pages PCL Font List

Sample Pages

Supplies Info Maintenance Kit Life

Graphics Demonstration
Total Print Count
Office Demonstration
2-Sided Demonstration**
Print Mode Demonstration
Walk-UpTM Features* CMYK Sampler Pages
RGB Sampler Pages
Secure Print Jobs*****

Proof Print Jobs*****

Saved Print Jobs*****

Walk-Up PrintingTM

Select for Installation

TCP/IP Setup TCP/IP

NetWare Setup DHCP/BOOTP
Printer Setup
Ethernet Speed AutoIP
EtherTalk TCP/IP Address
Configuration Page Connection Setup Page
TCP/IP Network Mask
Network Setup*
Connection Setup TCP/IP Gateway
Parallel Setup Parallel Port
Port 9100
USB Setup Wait Timeout
LPR
Reset Connection Setup Page Description Language
IPP
Job Pipelining*
SLP
SSDP
USB Port CentreWare IS
Wait Timeout
Requires: Page Description Language NetWare
* Network Configuration Job Pipelining* IPX Frame Type
** Duplex Configuration
*** Optional Lower Tray(s)
**** Hard Drive Page 1 of 2
***** 8400DX only with stored jobs present

A-4 Phaser 8400/8500/8550 Color Printer

 Paper Source
2-Sided Printing**
Tray 1 Setup
PostScript Error Info Font Number
Tray 2 Paper Type
Print-Quality Mode Pitch
Tray 3 Paper Type***
TekColor Correction Point Size
Printer Setup Tray 4 Paper Type***
Image Smoothing Symbol Set
(continued) Load Paper Timeout
Reset PostScript Setup Orientation
Cleaning Page Source
Form Length
Paper Handling Setup Reset Paper Handling Setup
Line Termination
PostScript Setup Draft Mode
Reset PCL Setup
PCL Setup

Front Panel Setup Front Panel Language

Front Panel Brightness
Printer Controls Startup Page
Front Panel Contrast
Power Saver Timeout
Accessible Front Panel
Date and Time
Reset Front Panel Setup
Intelligent Ready
Metric Defaults
Reset Printer Controls

Troubleshooting

Help Guide Paper Tips Page Troubleshooting Print Quality

Online Jam Prevention Guide Page
Paper Jams Paper Path Test Eliminate Light Stripes
Remove Print Smears
Print Quality Problems

Network Log Pages* NetWare Start Log

NetWare Runtime Log
Service Tools Printer Status Page
TCP/IP Start Log
Engine Error History
TCP/IP Runtime Log
Jam History
AppleTalk Start Log
Diagnostics History
AppleTalk Runtime Log
Enter Diagnostic Mode
Service Usage Profile
Email Service Report*
Reset NVRAM

Shutdown

Power Saver (Recommended)

Restart Printer

Power Down To minimize ink usage, leave the printer on.

Requires:
* Network Configuration
** Duplex Configuration
*** Optional Lower Tray(s)
**** 8400DX only with stored jobs present Page 2 of 2

Service Manual A-5

Media Margin Specification Table

Top/
Side Bottom Image Image
Width Length Margins Margin Width Length
Media Size (mm) (mm) (mm) (mm) (mm) (mm)

Legal 215.9 355.6 5 5 205.9 345.6

Folio 215.9 330.2 5 5 205.9 320.2

A4 210 297 5 5 200 287

A 215.9 279.4 5 5 205.9 256.7

Executive 187.15 266.7 5 5 174.15 256.7

B5 JIS 182 257 5 5 172 247

B5 ISO 176 250 5 5 166 240

#10 Envelope 104.775 241.3 5 15 94.775 211.3

Choukei 3 Gou 120 235 5 15 105 205

C5 Envelope 162 229 5 20 157 189

DL Envelope 110 220 5 20 100 180

Statement 139.7 215.9 5 5 129.7 205.9

A5 148 210 5 5 138 200

Choukei 4 Gou 90 205 5 15 80 175

Monarch Envelope 98.425 190.5 5 15 88.425 160.5

A7 Lee Envelope 133.35 184.2 5 15 123.35 154.2

#6 3/4 Envelope 92.075 165.1 5 15 82.075 135.1

A6 105 148 5 5 95 138

#5-1/2 Baronial 111.125 146 5 15 101.125 112.9

3 x 5 Card 76.2 127 5 5 66.2 117

6 x 9 Envelope 152.4 228.6 5 20 142.4 188.6

Custom 76.2 - 127 - 12.5 12.5 51.2 - 102 -

215.9 355.6 (8400) 190.9 330.6
5 mm
(8500)

A-6 Phaser 8400/8500/8550 Color Printer

Paper Weight Equivalence Table
US US Bond US Text US US US Index US Tag Metric
Postcard Weight Book Cover Bristol Weight Weight Weight
Thickness (lb.) Weight Weight Weight (lb.) (lb.) (g/m2)
(mm) (lb.) (lb.) (lb.)

16 41 22 27 33 37 60

17 43 24 29 35 39 64

20 50b 28 34 42 46 75

21 54 30 36 44 49 80
24 60b 33 41 50 55 90

27 68 37 45 55 61 100

28 70b 39 49 58 65 105
29 74 41 50 61 68 110

32 80b 44 55 67 74 120

36 90 50 62 75 83 135

0.18 39 100 55 67 82 91 148

40 101 55 68 83 92 150

0.20 43 110 60 74 90 100 163

45 115 63 77 94 104 170

0.23 47 119 65 80 97 108 176

51 128 70 86 105 117 190

53 134 74 90 110 122 199

54 137 75 93 113 125 203

58 146 80 98 120 133 216

65 165 90 111 135 150 244

Service Manual A-7

On-site Printhead Troubleshooting Checklist (8400)

PRINTHEAD TROUBLESHOOTING CHECKLIST

Phaser 8400/WorkCentre C2424 Version 2

IMPORTANT! This checklist outlines proper printhead troubleshooting procedures. All Xerox service employees and
any other service personnel on any job involving a printhead replacement should perform it.

Service person name

Service Company

Phone Number

Date of printhead replacement

Printer serial number

Printhead serial number

OUT Request ID number

Troubleshooting Summary – Follow the checklist below and fill in spaces as they apply as you complete
the troubleshooting procedures.

Check List Value What to look for

Items to or
Complete Result
Step Do you suspect 1a. Did the customer state that they have used generic ink in this
1 or have YES printhead? YES NO
evidence of use NO 1b. Did you observe generic sticks or related packaging at the site?
of generic ink? YES NO
Circle 1c. Are there generic ink sticks in the ink loader?
one
YES NO
1d. Does the service history indicate possible use of generic ink?
YES NO
Indicate brands and lot codes of generic ink if used:
______________________________________________

If you answered YES to any of the above, be sure to document the

use of non-Xerox ink in the Comments section of this document.
Xerox U.S. personnel and Service Delivery Partners please record
non-Xerox ink use in the FIST system as well as in this document.

Xerox Phaser 8400/WorkCentre C2424 Printhead Checklist 075-0882-02 Page 1

A-8 Phaser 8400/8500/8550 Color Printer

 Step Print the
If Line 631 Printhead ID:
2 Service Usage
Printhead ID 00-09: _______________
Profile. It is
lists a date, record the date 10-29: _______________
located in the
(month day year) here: 30-99 _______________
front panel
100+: _______________
menu
Troubleshooting If Line 636 IDU:
– Service Tools. IDU lists any values, record 00-09: _____________
the numbers here: 10-29: _____________
30-99 _____________
100+: ______________
Xerox U.S. personnel please record these dates in the FIST system as
well as in this document
Step Does the printer YES If YES please write down the error code. _______________
3 display an error NO
code indicating 3a. If error code 13,264.4x is present in the Fault History replace the
a problem with Circle electronics module (continue to 3b).
the printhead? one
3b. If a printhead thermistor open or shorted error code 13,195.45,
13,197.47, 13,259.46, 13, 261.48, 13,323.47, 13.325.49 is
displayed or a PEST error code 37,002.47, 37,003.48, 37,004.40,
or 37,005.41, perform the following steps:
3c. Inspect and reseat the printhead interface cable (gray ribbon
cable) and retest.
3d. Replace the electronics module and retest.
3e. Replace the printhead.
Step Visually inspect If NO, replace the printhead. The repair is complete!
4 the ink YES
reservoirs. Do NO Ink visible in reservoirs
they all contain
ink? Circle
one
No ink in a
reservoir,
accompanied
by many
missing jets
before and
after a purge
cycle, indicates
that an ink-level
sensor has
failed.
Step Has the printer If YES, replace the wiper assembly. Proceed to Step 9.
5 had a printhead YES
replaced before NO The new wiper assembly may take 6 purges to before achieving optimal
for a (non-NXI performance. Ensure the wiper assembly is correctly aligned with the
related) weak or Circle printhead.
missing jet one If the missing jet(s) recovers, the repair is complete.
problem?

Xerox Phaser 8400/WorkCentre C2424 Printhead Checklist 075-0882-02 Page 2

Service Manual A-9

 Step Is the Wiper Is the wiper assembly out of alignment (not parallel with the printhead
6 Assembly YES faceplate)?
correctly NO If YES, perform the wiper alignment procedure as described in the
aligned? Phaser 8400 Color Printer Service Guide.
Circle
one
Step Print Service Is there color mixing from one row to the next row for the same jet?
7 Test Print 1: YES Note: Some color mixing is normal following a purge. It
Weak and NO usually clears after one or two prints.
Missing Jets. If YES, replace the wiper assembly. Repeat Step 6.
Is severe color Circle
mixing one
apparent?
Step Visually check Are there streaks, smudges, or a scum of wax in the jet area (outlined in
8 the printhead YES red) of the printhead?
faceplate. Is NO
the faceplate
contaminated? Circle
one

If YES, replace the wiper assembly.

Repeat the checklist starting at Step 6.

Step Visually check Is there any damage or separation on the wiper blade? If YES, replace
9 the Wiper the wiper assembly.
Assembly
blade. Is it OK?
Step Check the Check the purge pump performance.
10 purge YES 10a. Empty the waste tray.
performance of NO 10b. Select Eliminate Light Stripes from the printer front panel and
the purge run one cleaning cycle.
system. Circle 10c. Remove the waste tray and examine how much ink was purged.
one
A single purge should resemble the illustration.

Is the purge mass noticeably less than what is pictured?

If YES, inspect the purge hoses for kinks, splits or tears.

Xerox Phaser 8400/WorkCentre C2424 Printhead Checklist 075-0882-02 Page 3

A-10 Phaser 8400/8500/8550 Color Printer

 Step Print Service x If NO go to Step 12.
11 Test 1: Weak YES x If YES, do the following:
and Missing NO x Check the exit area of the paper path for debris that could be
Jets. scraping ink off the drum and may mimic a weak or missing jet.
Are there weak Circle
one
x Select Eliminate Light Stripes from the printer front panel up to
or missing 3 times as needed to recover a weak or missing jet.
jet(s)? x Perform the JetFix technique by downloading the appropriate
snippet (such as 8400_jetfix_c.ps for a missing cyan jet) to the
printer. The snippets are available on the Customer Support
Resources website in the Phaser 8400 web pages. Refer to
Service Bulletin 640.
x If the jet is still missing, replace the printhead. The repair is
complete!
Step Is the customer x If YES, print 10 solid fill pages of cyan. If the bands vary in intensity
12 experiencing YES and/or location over the 10 prints, the customer is experiencing
vertical bands NO stagnant ink discoloration. Continue to print solid fills of the
(not light offending color until the output is uniform. It may take as many as 60
stripes) in solid Circle solid fill pages to refresh all of the ink in the printhead reservoir. The
color areas? one
repair is now complete!
x If No, the repair is complete!

Comments: (Xerox U.S. personnel please add all comments into FIST)
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________

A completed checklist and sample prints must be returned with each printhead.
Xerox reserves the right to refuse reimbursement to service personnel who do not enclose a
completed troubleshooting checklist and a sample print with each returned printhead.
Please return the following items with the defective printhead:
x Two prints of Service Print 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88
Service Print 1
x This Printhead Troubleshooting Checklist (filled out)
x Inventory control “Green Tag” (filled out)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88

x Sample prints that clearly show the observed print quality 74 75 76 77 78 79 80

Weak jet
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88

defect (not applicable for printheads replace because of an

error code) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88

9923-114

Xerox Phaser 8400/WorkCentre C2424 Printhead Checklist 075-0882-02 Page 4

Service Manual A-11

 GENERIC INK FAILURE CHECKLIST
PERFORM THIS CHECKLIST ONLY IF YOU SUSPECT
NON-XEROX INK IS BEING USED.

Step Print Test Print 1 (Weak/Missing Jets). CAREFULLY examine it. If YES If NO
1 Does Test Print 1 show at least one color with 8 or more Go to Step 3 Go to Step 2
weak/missing jets?
Step Run 10 solid fills in the suspected color from the front panel. Does If YES If NO
2 the number of weak and missing jets noticeable increase with solid Go to Step 3 Go to B
fills.
Step Does the printhead reservoir of the affected color have a large If YES If NO
3 visible pool of ink obscuring the surface of the filter element? Go to B Go to A

Ink not visible. Filter viewable. Visible pool of ink obscuring filter.
Ink passing easily thru filter. Ink not readily passing thru filter.

A Generic Ink Failure. B Does not fully meet field criteria.

Suspected generic ink failure.
x Inform the customer that service will only be
provided with a credit card or purchase x Inform the customer that although the Field
order. The Xerox warranty/Service Generic Ink Failure Test Criteria was not
Agreement DOES NOT cover repair cost of satisfied, engineering will further evaluate
the printhead when it has been damaged by the printhead upon its return to the factory.
non-Xerox ink and the repair cost is the It will be subjected to complete analysis at
responsibility of the customer. that time and, if found to be damaged by
x Provide the customer with the “Diagnosis Form” generic ink, the customer will be billed.
and “Onsite Failure notification” letters. x Provide the customer with the “Customer Alert
x Once payment has been authorized or assured, #8 March 2005” letter.
replace the printhead and included ink per x If there are weak or missing jets replace the
normal procedures. printhead and included ink per normal
x Check the “Non-Xerox/Tektronix” Ink box on procedures.
the Green tag. x Check “Non-Xerox/Tektronix” Ink box on the
x Enclose all sample prints (including two prints Green tag.
of Service Print 1), ink samples, waste ink, and x Enclose all sample prints (including two prints
this checklist with the printhead. of Service Print 1), ink samples, waste ink,
Xerox Personnel – Please provide full documentation and this checklist with the printhead.
in FIST. Xerox Personnel – Please provide full
documentation in FIST.

IN EITHER CASE PLEASE NOTE ADDITIONAL GENERIC INK INFORMATION

x Was generic ink or related packaging observed? YES NO
x Was generic ink present in the ink loader? YES NO
IMPORTANT – Note the brand and lot code of the generic ink, if available

Xerox Phaser 8400/WorkCentre C2424 Printhead Checklist 075-0882-02 Page 5

A-12 Phaser 8400/8500/8550 Color Printer

On-site Printhead Troubleshooting Checklist (8500/
8550)

PRINTHEAD TROUBLESHOOTING CHECKLIST

Phaser 8500/8550 Version 1.0

IMPORTANT! This checklist outlines proper printhead troubleshooting procedures. All Xerox service employees and
any other service personnel on any job involving a printhead replacement should perform it.

Service person name

Service Company

Phone Number

Date of printhead replacement

Printer serial number

Printhead serial number

OUT Request ID number

Troubleshooting Summary – Follow the checklist below and fill in spaces as they apply as you complete
the troubleshooting procedures.

Check List Value What to look for

Items to or
Complete Result
Step Do you suspect 1a. Did the customer state that they have used generic ink in this
1 or have YES printhead? YES NO
evidence of use NO 1b. Did you observe generic sticks or related packaging at the site?
of generic ink? YES NO
Circle 1c. Are there generic ink sticks in the ink loader?
one
YES NO
1d. Does the service history indicate possible use of generic ink?
YES NO
Indicate brands and lot codes of generic ink if used:
______________________________________________

If you answered YES to any of the above, be sure to document the

use of non-Xerox ink in the Comments section of this document.
Xerox U.S. personnel and Service Delivery Partners please record
non-Xerox ink use in the FIST system as well as in this document.

Xerox Phaser 8500/8550 Printhead Checklist 0750984-00 Page 1

Service Manual A-13

 Step Print the
If Line 631 Printhead ID:
2 Service Usage
Printhead ID 00-09: _______________
Profile. It is
lists a date, record the date 10-29: _______________
located in the
(month day year) here: 30-99 _______________
front panel
100+: _______________
menu
Troubleshooting If Line 636 IDU:
– Service Tools. IDU lists any values, record 00-09: _____________
the numbers here: 10-29: _____________
30-99 _____________
100+: ______________
Xerox U.S. personnel please record these dates in the FIST system as
well as in this document
Step Does the printer YES If YES please write down the error code. _______________
3 display an error NO
code indicating 3a. If error code 13,264.4x is present in the Fault History replace the
a problem with Circle electronics module (continue to 3b).
the printhead? one
3b. If a printhead thermistor open or shorted error code 13,195.45,
13,197.47, 13,259.46, 13, 261.48, 13,323.47, 13.325.49 is
displayed or a PEST error code 37,002.47, 37,003.48, 37,004.40,
or 37,005.41, perform the following steps:
3c. Inspect and reseat the printhead interface cable (gray ribbon
cable) and retest.
3d. Replace the printhead. The repair is complete!

Visually inspect If NO, replace the printhead. The repair is complete!

the ink YES
reservoirs. Do NO Ink visible in reservoirs
they all contain
ink? Circle
one
No ink in a
reservoir
indicates that
an ink-level
sensor has
failed.

Step Has the printer If YES, replace the wiper assembly. Proceed to Step 9.
5 had a printhead YES
replaced before NO The new wiper assembly may take 6 purges to before achieving optimal
for a (non-NXI performance. Ensure the wiper assembly is correctly aligned with the
related) weak or Circle printhead.
missing jet one If the missing jet(s) recovers, the repair is complete.
problem?

Xerox Phaser 8500/8550 Printhead Checklist 0750984-00 Page 2

A-14 Phaser 8400/8500/8550 Color Printer

 Step Is the Is the wiper assembly out of alignment (not parallel with the printhead
6 Cap/Wipe/ YES faceplate)?
Purge assembly NO If YES, perform the wiper alignment procedure as described in the
correctly Phaser 8400/8500/8550 Color Printer Service Guide.
aligned? Circle
one
Step Print Service Is there color mixing from one row to the next row for the same jet?
7 Test Print 2: YES Note: Some color mixing is normal following a purge. It
Weak and NO usually clears after one or two prints.
Missing Jets. If YES, replace the wiper assembly. Repeat Step 6.
Is severe color Circle
mixing one
apparent?
Step Visually check Are there streaks, smudges, or a scum of wax in the jet area (outlined in
8 the printhead YES red) of the printhead?
faceplate. Is NO
the faceplate
contaminated? Circle
one

If YES, replace the wiper assembly. Repeat the checklist stating at Step
6.
Step Visually check Is there any damage or separation on the wiper blade? If YES, replace
9a the Wiper the wiper assembly.
Assembly
blade. Is it OK?
Step Check the Check the purge pump performance.
9b purge YES 9a. Empty the waste tray.
performance of NO 9b. Select Eliminate Light Stripes - Basic from the printer front
the purge panel and run one cleaning cycle.
system. Circle 9c. Remove the waste tray and examine how much ink was purged.
one
A single purge should resemble the illustration.

Is the purge mass noticeably less than what is pictured?

If YES, inspect the purge hoses for pinches, splits, or tears.

Xerox Phaser 8500/8550 Printhead Checklist 0750984-00 Page 3

Service Manual A-15

 Step Print Service x If NO go to Step 12.
11 Test 2: Weak YES x If YES, do the following:
and Missing NO x Check the exit area of the paper path for debris that could be
Jets. scraping ink off the drum and may mimic a weak or missing jet.
Are there weak Circle
one
x Select Eliminate Light Stripes - Basic from the printer front
or missing panel up to 3 times as needed to recover a weak or missing jet.
jet(s)? x Select Eliminate Light Stripes - Advanced from the printer front
panel up to 2 times as needed to recover a weak or missing jet.
x Select Jet Substitution to substitute a working jet for the
missing jet. However, if any of the following criteria is met, you
should replace the printhead instead.
x If the customer uses the billing meters features.
x If three missing jets of the same color are adjacent (for
example cyan jets 79, 80, and 81).
x By the customer runs mainly in Fast Color or Standard mode
(as revealed on the Usage Profile page).
The repair is complete!
Step Is the customer x If YES, print 10 solid fill pages of cyan. If the bands vary in intensity
12 experiencing YES and/or location over the 10 prints, the customer is experiencing
vertical bands NO stagnant ink discoloration. Continue to print solid fills of the
(not light offending color until the output is uniform. It may take as many as 60
stripes) in solid Circle solid fill pages to refresh all of the ink in the printhead reservoir. The
color areas? one
repair is now complete!
x If No, the repair is complete!

Comments: (Xerox U.S. personnel please add all comments into FIST)
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________

A completed checklist and sample prints must be returned with each printhead.
Xerox reserves the right to refuse reimbursement to service personnel who do not enclose a
completed troubleshooting checklist and a sample print with each returned printhead.
Please return the following items with the defective printhead:
x Service Print 1 (not necessary for error code-based
failures (not applicable for printheads replace because of
an error code)
x This Printhead Troubleshooting Checklist (filled out)
x Inventory control “Green Tag” (filled out)
x Sample prints that clearly show the observed print quality
defect (not applicable for printheads replace because of an
error code)

Service Print 1

Xerox Phaser 8500/8550 Printhead Checklist 0750984-00 Page 4

A-16 Phaser 8400/8500/8550 Color Printer

Index
Numerics ink loader, 8-9
media drive motor, 8-37
525-sheet feeder, parts list, 9-9
pick solenoid, 8-49
8-pin NVRAM, parts list, 9-13
power cord parts list, 9-16
printhead data, 5-8
A printhead power, 3-18
AC power, 2-20 ribbon connector, 8-6
adjust x-axis scale, service menu, 4-3 serial modem, 4-85
USB, 4-84
wave amp, 3-45
B cabling, parts list, 9-13
back button, 1-5 calibration faults, 3-36, 3-39
basic positions, printhead, 2-10 calibrations, printer, 6-10
basic printhead cleaning cycle, 2-33 camshaft assembly, 2-4
belts cancel button, 1-5
drive, single reduction, 2-17 chase page, 2-34, 4-3, 4-64
drum, 2-17 check menu tables, 4-12
parts for wiper drive, 9-7 check activators menu, 4-13
parts for y-axis, 9-7 deskew clutch, 4-13
printer, 7-6 drum heater relay, 4-15
removing from drum assembly, 8-34 head maintenance clutch, 4-13
wiper alignment, 6-3 purge vent solenoid, 4-15
y-axis disassembly, 8-9 strip solenoid, 4-14
y-axis slip test, 3-65, 4-45 tray 1 pick solenoid, 4-13
y-axis tension, 3-16 tray 2, tray 3, tray 4, pick clutch,
y-axis tension test, 4-45 4-14
BIST Error Codes, 3-3 check drive menu, 4-35
drum maintenance drive, 4-39
paper path drive, 4-36
C tilt drive, 4-40
cables transfix drive slow and transfix
circuit board and cables part list, 9-13 drive fast, 4-38
crossover, 4-82 tray 2, tray 3, tray 4, lift plate
drum encoder, 8-34 drive, 4-41
drum heater, 8-34 wiper drive, 4-35
drum thermister, 8-34 x-axis drive, 4-37
exit module, 8-38 check drum menu, 4-42
I/O and electronic, 3-28 drum maintenance contact, 4-47
IDE hard drive, 2-19 stripper contact, 4-46

Service Manual Index – 1

 y-axis belt slip, 4-45 Clear ISC Fault, 4-11
y-axis belt tension, 4-45 clevis pins, 8-28, 8-35, 8-37
y-axis drive, 4-44 closed-loop servo motor, 2-17
y-axis encoder, 4-42 communication ports, 2-19, 4-82
y-axis geometry, 4-43 configuration card
check misc menu, 4-53 8400 series, 1-3
drum maint/transfix home, 4-58 8500 series, 1-4
paper path status, 4-53 theory, 2-19
purge pump, 4-55 view, 1-8
temperature status, 4-54 configuration, control panel, 1-5
voltages, 4-56 consumables, 9-17
wiper alignment, 4-57 diagram, 1-9
check motors menu, 4-48 life counters, 1-9
media path motor, 4-50 control panel
process motor, 4-49 LED indicators, 1-5
tray 2, tray 3, tray 4, lift motor, menu map, 1-6
4-51 covers
tray 3 and tray 4 pick/feed mo- control panel, 8-6
tor, 4-51 exit, 8-7
x-axis motor, 4-48 front door assembly, 8-5
y-axis motor, 4-48 left side, 8-7
check paper path menu, 4-20 right side, 8-6
duplex paper drive power, 4-31
duplex paper lead edge times,
4-32 D
duplex paper sensor bounce DC power, 2-21
times, 4-34 deskew clutch, 4-17
duplex paper trail edge times, deskew clutch test, 4-13
4-33 deskew clutch, disconnecting, 8-48
paper drive power, 4-25 deskew process, 2-26
paper lead edge times, 4-26 deskew rollers, 2-27
paper sensor bounce times, 4-30 diagnostic firmware, 3-36
paper trail edge times, 4-28 diagnostic history, 3-2
tray 1 pick shaft, 4-22 diagnostic test functions, 3-2
tray 2, tray 3, and tray 4 pick diagnostics
shaft, 4-24 process motor, 3-19
wiper shaft, 4-20 tilt axis, 3-19
check shafts menu, 4-17 transfix drive, 3-19
deskew shaft, 4-17 x-axis, 3-18
cleaning y-axis encoder, 3-16
ink smears, 7-3 diagnostics menu, hidden service, 3-9
light stripes or missing colors, 7-3 diagnostics, service, 4-4
media jams, 7-3 DIMM, 1-8
cleaning cycle, 2-33 disassembly notes, 8-3
cleaning page, 2-14, 2-33, 5-44 disassembly procedures
cleaning procedures, 7-2 control panel cover, 8-6

Phaser 8400/8500/8550 Color Printer Index – 2

 covers, 8-6 assembly and transfix system, 2-16
DIMM chips, 8-60 drum cleaning, 2-34
drum heater relay, 8-58 drum preparation, 2-24
drum maintenance assembly, 8-32 maintenance system, 2-13
duplex roller, 8-23 purge system, 2-14
electronics module, 8-55 relation to printhead, 2-10
exit module assembly, 8-40 drum preparation, 2-24
front door assembly, 8-5 duplex printing, 2-30
hard drive, 8-61 duplex roller
head tilt compound gear, 8-54 disassembly, 8-25
head tilt solenoid, 8-18 parts, 9-9
I/O board, 8-57
ink loader assembly, 8-8
media drive gearbox, 8-48 E
media release blade and roller, 8-22 electrical troubleshooting, 4-65
NVRAM, 8-59 electronics module, 2-19
paper guides, 8-41 BIST errors, 3-3
pick assembly, 8-45 DIMM replacement, 8-60
pick solenoid, 8-49 failures, 4-71
preheater and deskew assembly, 8-23 I/O board faults, 3-11
preheater lift solenoid, 8-50 interface faults, 3-27
printhead assembly, 8-12, 8-20 location, 1-8
processor drive motor, 8-51 NVRAM replacement, 8-59
purge pressure pump, 8-39 overview, 2-3
takeaway roller, 8-44 parts list, 9-13
wave amp board, 8-56 POST errors, 3-4
x-axis bias spring, 8-19 replacement, 8-55
x-axis motor assembly, 8-53 theory of operation, 2-19
y-axis motor assembly, 8-9 electronics subsystem, 2-3
dot size variations, 5-37 eliminate light stripes, 2-33, 5-2
drop mass evaluation, 5-34 eliminate light stripes, service menu, 4-2
drum assembly, 2-3, 2-16 energy guidelines, 4-3
drum assembly, parts, 9-7 envelopes, printing on, 1-13
drum cleaning, 2-34 environmental specifications, 1-11
drum heater, 2-16 error codes
drum maintenance, 2-24 525-sheet feeder faults, 3-10
camshaft, 6-8, 8-52 code version, 3-36
camshaft assembly parts, 9-7 electronics module, 3-27
definition, 2-3 I/O board program, 3-11
door part number, 9-5 I/O circuit board, 3-11
pivot plate, 8-32 ink loader, 3-26
pivot plate part, 9-7 IPC program, 3-12
removing pivot plate, 8-33 mechanical initialization, 3-37
theory, 2-13 printhead calibration, 3-36
drum maintenance system, 2-3 process control system, 3-13
drum operation process motor gearbox, 3-19

Service Manual Index – 3

 thermal faults, 3-29 H
wiper/media path, 3-24
hard drive, 1-8
x-axis fault, 3-18 parts list (all series), 9-13
y-axis sub-system, 3-16 POST error, 3-8
ethernet address, configuration card, 2-19 replacement note, 8-55
exit module replacement procedure, 8-61
all-series parts, 9-9
support, 2-19
assembly parts, 9-9 upgrade kit parts, 9-17
sensor assembly parts, 9-15
head tilt gear, homing, 6-5
exit rollers, 2-5, 2-27, 2-30
heater harness, 8-15
exit rollers, parts, 9-9
heaters, ink reservoir, 2-8
exiting, 2-27
hidden service menu, 4-5
home position, 6-4
F
fan I
drum, 2-16
I/O board, faults, 3-11
drum cooling parts, 9-11
imaging components, disassembly, 8-9
drum diagnostics, 5-37
incomplete image, 5-26
drum disassembly, 8-34
indicators, LED, 1-5
electronics module parts, 9-11
ink jet damage, 8-13
media path motor, 4-8
ink loader
paper path parts, 9-11
faults, 3-26
temperature error, 3-29
function, 2-3
fan, electronics, 3-29
theory, 2-6
fans menu, check menu, 4-6
ink loader, disassembly, 8-8
fault codes, 3-9
ink smears, 5-28
fault history, hidden service menu, 4-2
ink-out sensor, 2-6
field replaceable units, 8-2
input/output Ports, 2-19
front door
assembly, stay, and retainer, 9-5
hinge pin parts, 9-5 J
removal, 8-5 jam code tables, 3-56
tray 1 assembly, 8-5 jam codes, 3-55
function menu, service diagnostics, 4-10 jet nozzles, 2-7
functional specification, 1-11 jet stack, 2-8
fuzzy text, 5-17 jet substitution, 2-24, 6-10

G L
ghosting, 5-20 lift motor, 4-9, 4-51
ground connection integrity, 4-77 lift motor, disassembly, 8-47
ground connection warning, 1-ii lower inner duplex guide
ground integrity, 4-77 parts list, 9-9
grounding, 4-77 removal, 8-41
guidelines, energy, 4-3 lubrication, 7-6

Phaser 8400/8500/8550 Color Printer Index – 4

M paper path
check menu, 4-20
main board electronics module, 2-19
drive problems, 4-36
main board memory, 2-19
exit module assembly, 8-40
main subsystems, 2-2
ink residue, 5-6
maintenance kit, 7-5
jams, 3-37
maintenance kit, eprom chip, 2-13
motor jam codes, 3-64
mechanical initialization, 4-60, 4-62
parts list, 9-9
media drive
problems, 3-24
assembly parts, 9-11
scratches or marks, 5-13
function, 2-3
status, 4-53
gearbox removal, 8-48
temperature problems, 5-28
theory, 2-5
theory, 2-26, 2-34
media path drive, 2-3
paper pick
media path faults, 3-37
errors, 4-79
miscellaneous error codes, 3-36
theory, 2-25
parts list, usage, 9-2
N personality parameters, 2-19, 2-20, 2-35
NVRAM, 1-8, 2-19 PEST Error Codes, 3-8
NVRAM, reset, 6-12 PEST error reporting, 3-8
PEST tests, 3-8
Phaser features
O 8400 series, 1-3
oil streaks, 5-24 8500 series, 1-4
oiling cycle, 2-34 physical dimensions, 1-10
outer duplex guide pick roller
illustration, 8-42 cleaning, 7-4
paper path part, 9-9 disassembly, 8-45
removal, 8-41 feeder faults, 3-10
jam codes, 3-73
media skews, 4-81
P parts assembly, 9-9
paper skew margins, 5-42
color media, 9-19 theory, 2-5
jam, 2-34 pivot plate, 2-13
main tray, 9-9 poor primary colors, 5-19
media specifications, 1-12 POST error codes, 3-5
pick process, 2-25 POST error reporting, 3-4
preheater, 2-16 POST tests, 4-2
present flag, 9-15 power control board, 2-20
printing process, 2-16 power supply, 2-20
transfix and print speeds, 2-31 power supply operation, 4-75
transfixing and editing, 2-27 power supply, verifying, 4-75
transport system, 2-3, 2-5 power-up sequence, 4-59
predominate light stripes, 5-5
preheat exit sensor, 2-27

Service Manual Index – 5

preheater relation to printhead, 2-11
cleaning, 2-33, 2-34 relation to transfix system, 2-18
disassembly, 8-23 theory, 2-4
errors, 3-31 process gear drive train, homing, 6-8
function, 2-16 purge pump, 8-13
fuses, 2-20 purge system, 2-3, 2-14
ink smears, 5-28 purging, 2-33
jams, 4-80
lift solenoid disassembly, 8-50
parts, 9-7 R
smudges or smears, 5-6 random light stripes, 5-3
temperature, 4-54 regulatory information
test, 3-31 Canada, 1-iii
thermister, 3-31 Europe, 1-iii
transfixing, 2-27 United States, 1-iii
print position, 2-11 remove print smears, 2-34
print process, 2-23 retard roller, 2-26
print quality problems menu, 2-34 roll block, 8-14
print speeds, 2-31 routine maintenance items, 1-9
print-eject jams, troubleshooting, 4-80
printer clearances, 1-10
printer orientation, 8-2 S
printer part locator, 1-7 scratches, 5-13
printer view self maintenance functions, 2-33
rear, 1-8 self-maintenance cycles, 2-33
right side with interfaces, 1-7 sensors, 2-22
printer, inspecting, 7-6 service diagnostics, 4-4
printhead, 2-3 service menu, hidden, 4-2
printhead maintenance cycle, 2-14 silicone oil, 2-13
printhead movement, 2-10 six-jet interlace, 2-24
printhead overview, 2-3 smudges or smears, 5-6
printhead restraints, disassembly, 8-12 specifications
printhead theory, 2-7 electrical, 1-11
printhead tilt, 2-10 environmental, 1-11
printhead, disassembly, 8-12 functional, 1-11
print-quality defects, 5-2 media and tray, 1-12
process control faults, 3-13 physical dimensions, 1-10
process drive, 2-18 specifications, printer, 1-10
assembly train, 6-4 status indicator LED, 1-5
definition, 2-3 streaks, 5-11
error faults, 3-19 supplies, Xerox, 9-16
homing, 6-8, 8-52
parts list, 9-11
relation to drum, 2-13

Phaser 8400/8500/8550 Color Printer Index – 6

T
test prints, 5-33
tilt cam, 2-10, 2-11
tilt gear, 2-12
transfix roller, 2-16, 2-18, 2-27
transfix speeds, 2-31
transfix system, 2-3, 2-16
transfixing, 2-27
troubleshooting, jam codes, 3-57

U
uneven color, 5-9

W
waste ink, 2-14
waste tray, 7-5
wavy vertical lines, 5-23
wiper alignment procedure, 6-2
wiper assembly lock, 8-12
wiper faults, 3-24
wiping, 2-33
wiring
inside front, 10-8
inside top, 10-9
left-side, 10-6
main wiring, 10-2
printhead, 10-10
right-side, 10-4
wrinkling, 5-31

X
x-axis bias spring hook, 8-13
x-axis faults, 3-18, 3-19
x-axis system, 2-9

Y
y-axis belt, disassembly, 8-9
y-axis faults, 3-16

Service Manual Index – 7