010-311 Fusing Unit Center Thermistor Defect 010-320 Over Heat Temperature Fail

BSD-ON:CH10.2 BSD-ON:CH10.2, CH10.1

An open circuit abnormality (the AD value of the STS is equivalent to the open circuit value) of the Heat A high temperature error was detected at the Center Thermistor (245 degrees C or higher) or the Rear
Roll Center Thermistor was detected. Thermistor (270 degrees C or higher).

Procedure NOTE: To clear this Fail, first remove the cause, next clear the value of NVM [744-040] (Over Heat Temp
Turn OFF the power and disconnect the Heat Roll Center Thermistor connector P/J600. Measure the Fail) to '0', and then turn the power OFF then ON. The relationship between the displayed value and the
Thermistor that detected the high temperature error is as follows:
resistance between the Heat Roll Center Thermistor J600 pin-1 and J600 pin-2. Is the resistance infi-
nite? • 0: Normal
Y N • 1: High Temperature Error of Heat Roll Center Thermistor
Reconnect the connector P/J600 and measure the resistance between the ESS/MCU PWB J403 • 2: High Temperature Error of Heat Roll Rear Thermistor
pin-1 and J403 pin-2. Is the resistance infinite?
Y N Cause/Action
Replace the ESS/MCU PWB. (PL 18.1) Check the following:

Check the following connections for open circuits and poor contacts. • The Center Thermistor or the Rear Thermistor for dropped parts, sensor contamination, and foreign
• Between ESS/MCU PWB J403-1 and Heat Roll Center Thermistor P600-4 substances blocking the sensor.
• Between ESS/MCU PWB J403-2 and Heat Roll Center Thermistor P600-3 • The Heat Roll for wound up, stuck paper.
• The Heat Roll Center Thermistor (Analog Monitor [010-050]) for operation failure.
Replace the Fusing Unit. (PL 7.1)
• The Heat Roll Rear Thermistor (Analog Monitor [010-051]) for operation failure.
• The Heater Rod for operation failure.
010-312 Fusing Unit Rear Thermistor Defect If no problem is found, replace the following parts in sequence:
BSD-ON:CH10.2
• Fusing Unit (PL 7.1)
• LVPS (PL 18.1)
An open circuit abnormality (the AD value of the STS is equivalent to the open circuit value) of the Heat
Roll Rear Thermistor was detected. • ESS/MCU PWB (PL 18.1)

Procedure
Turn OFF the power and disconnect the Heat Roll Rear Thermistor connector P/J600. Measure the 010-327 Fusing Unit On Time Fail
resistance between the Heat Roll Rear Thermistor J600 pin-3 and J600 pin-4. Is the resistance infi- BSD-ON:CH10.2, CH10.1
nite?
Y N Any of the following was detected:
Reconnect the connector P/J600 and measure the resistance between the ESS/MCU PWB J403
pin-3 and J403 pin-4. Is the resistance infinite? • The Heater Rod did not turn OFF within the specified time after the Heater Rod On.
Y N
• After power ON, the temperature of the Fusing Unit does not reach the specified value within the
Replace the ESS/MCU PWB. (PL 18.1) specified time.

Check the following connections for open circuits and poor contacts.
• Between ESS/MCU PWB J403-3 and Heat Roll Rear Thermistor P600-2 Cause/Action
• Between ESS/MCU PWB J403-4 and Heat Roll Rear Thermistor P600-1 Check the following:

Replace the Fusing Unit. (PL 7.1) • The Heater Rod for operation failure.
• The connection between the LVPS J511 and the Fusing Unit P10 for open circuit and poor contact
• The Center Thermistor for dropped parts, sensor contamination, and foreign substances blocking
the sensor.

Version 1.0 2012/06 CHAIN 10