TM 750-116

SUPERSEDES COPY DATED 14 MAY 1984

T E C H N I C A L M A N U A L

GENERAL PROCEDURES

FOR

PURGING AND CHARGING

O F

FIRE CONTROL INSTRUMENTS

DISTRIBUTION STATEMENT A: Approved for public release; distribution unlimited.

HEADQUARTERS, DEPARTMENT OF THE ARMY

MAY 1993
 WARNING

High pressure nitrogen gas is used during purging and charging of this equipment. Keep face and body clear of re-
lease valves. Failure to observe safety precautions may result in severe injury or death.

When using compressed nitrogen gas in confined areas, use extreme care; gas could cause asphyxiation.

Do not store compressed nitrogen gas tanks in upright position without securing in a rack or chaining to a wall or
support. Do not drop tank of compressed gas.

Handle instruments with radioluminous light source with care. To avoid possible radioactive contamination. do not
purge or charge an instrument that has a damaged or inoperative radioluminous light source. Immediately wrap in-
strument in plastic and notify the local Radiation Protection Officer (RPO).

Solvent vapors are toxic. Do not use solvent in a confined space. Avoid long periods of breathing solvent vapors
and/or contact with skin.

Compressed air presents a serious hazard. Its use for cleaning and drying purposes should be permitted only where
all other methods have failed. When it is necessary to use compressed air for cleaning or drying, adequate controls
must be provided to protect the user, adjacent operators, and other personnel in the area. The minimum amount of air
pressure required to perform the specific operations must be used. All users of compressed air must wear eye protec-
tion. Compressed air will not be used for cleaning purposes except where reduced to less than 30 psig.

a
 TM 750-116
C1

HEADQUARTERS
Department of the Army
Washington D.C., 24 November 1995
Change
No. 1
GENERAL PROCEDURES
FOR
PURGING AND CHARGING OF
FIRE CONTROL I N S T R U M E N T S

TM 750-116, dated 5 May 1993 is changed as follows:

1. Remove old pages and insert new pages as indicated below.

Remove Pages Insert Pages
2-1 thru 2-4 2-1 thru 2-4

2. New or changed material is indicated by a vertical bar in the margin of the page. Illustration changes are
indicated by a pointing hand adjacent to the illustrations.

3. File this change sheet in front of the publication for reference purposes.

Change 1
DISTRIBUTION: To be distributed in accordance with DA Form 12-34-E, block 0899
requirements for TM 750-116.
 *TM 750-116

HEADQUARTERS
TECHNICAL MANUAL DEPARTMENT OF ARMY
NO. TM 750-116 Washington, DC 5 May 1993

GENERAL PROCEDURES
FOR
PURGING AND CHARGING OF
FIRE CONTROL INSTRUMENTS

This manual is current as of 1 January 1993

REPORTING ERRORS AND RECOMMENDING IMPROVEMENTS

You can help improve this manual. If you find any mistakes or if you know of a way to improve the pro-
cedures, please let us know. Mail your letter, DA Form 2028 (Recommended Changes to Publications and
Blank Forms), or DA Form 2028-2, located in the back of this manual, direct to Commander, U.S. Army
Armament, Munitions and Chemical Command, ATTN: AMSMC-MAS, Rock Island, IL 61299-6000.
A reply will be furnished to you.

DISTRIBUTION STATEMENT A: Approved for public release; distribution unlimited.

TABLE OF CONTENTS

Page
LIST OF ILLUSTRATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iv
LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
CHAPTER 1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..1-1

Section I. General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1-1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
1-2 Maintenance Forms, Records, and Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1-3 Destruction of Army Materials to Prevent Enemy Use . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1-4 Reporting Equipment Improvement Recommendations (EIR) . . . . . . . . . . . . . . . . . . 1-1

*This manual supersedes TM 750-116 dated 14 May 1984, including all changes.

i
 TM 750-116

TABLE OF CONTENTS - Continued

Page

Section II. Equipment Description and Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1-5 Equipment Characteristics, Capabilities, and Features . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1-6 Safety, Care, and Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1-7 Corrosion Prevention and Control (CPC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

CHAPTER 2. GENERAL PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1

2-1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1

2-2 Setup of Purging and Charging Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2-3 Bleed Down of Purging and Charging Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2-4 Time Cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-3
2-5 Purging and Charging Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

CHAPTER 3. PURGING AND CHARGING SPECIFIC INSTRUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Section I. General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

3-1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1

Section II. Specific Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

3-2 Aiming Circle, M2A2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3-3 Binocular, M19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3-4 Collimator, M1A1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3
3-5 Computer, M21 Electronic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3
Ammo Select Unit
Cant Angle Sensor
Computer Unit
Gunner’s Control Unit
Output Unit
Rate Tachometer
3-6 Device, Alinement, M139/M140 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
3-7 Devices, Boresight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5
M26/M27
M26A1/M27A1
3-8 Mounts, Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6
M137
M145/M145A1
M149/M149E1
M187
3-9 Periscope, M65 Battery Commander’s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8
3-10 Periscopes, Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8
M28C
M30C
M32El and M32CE1
M35E1
M36 and M36E1
M42
M44A, M44A2, M44A3, M44A4, M44A1E1, M44A2E1
M47
M48
M901
M981

ii
 *TM 750-116

TABLE OF CONTENTS - Continued

Page
3-11 Quadrants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-17
M14 and M14A1
M15
M17
M18
3-12 Rangefinders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-18
Laser
AN/VVG-2
M17A1, M17B1C, and M17C
3-13 Sights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21
BFV TOW/TOW2 Subsystem
Backup Sight PN 12316793
Integrated Sight Unit
Commander’s Relay Assembly
8635466 Infinity Sight
M44C Infinity
M61 Computing
Commander’s Extension, PN12285300
Control Unit, Image
Gunner’s Auxilliary Sight, PN 12278900
Gunner’s Primary Sight, PN 12282140, PN 12549761-2,
PN 12549761-3, PN 9377279-2
Tank Thermal
Commander’s Display
Gunner’s Display
Head Assembly
Power Converter
Weapon, PN 12279200
3-14 Telescopes, Articulated.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27
M105D and M105F
M127 and M127A1
3-15 Telescopes, Elbow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-28
M114 and M114A1
M16A1D and M116 Series
M118 Series
M138
M139
3-16 Telescopes, Panoramic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-29
M12A7Q and M12A7S
M113 and M113A1
M115
M117 and M117A1
M137 and M137A1
M901A1
M981 FISTV

iii
TM 750-116

TABLE OF CONTENTS - Continued

Page
3-17 Telescopes, Straight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-32
M90A2
M134
3-18 Test Set, Receiver/Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33
3-19 Trainer, M55 Laser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-34
3-20 Unit, Reticle Projector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-34

APPENDIX A. REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

APPENDIX B. EXPENDABLE SUPPLIES AND MATERIALS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

APPENDIX C. ADDITIONAL SUPPLIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INDEX 1

LIST OF ILLUSTRATIONS

2-1 . . . . . . . . . Setup for Single Stage Fixture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1

2-2 . . . . . . . . . Setup for Two-Stage Fixture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2
3-1 . . . . . . . . . M2A2 Aiming Circle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2
3-2 . . . . . . . . . M19 Binocular . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2
3-3 . . . . . . . . . M1A1 Collimator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3
3-4 . . . . . . . . . Ammo Select Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3
3-5 . . . . . . . . . Cant Angle Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-4
3-6 . . . . . . . . . Computer Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-4
3-7 . . . . . . . . . Gunner’s Control Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-4
3-8 . . . . . . . . .0utput Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-4
3-9 . . . . . . . . . Rate Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5
3-10 . . . . . . . .Ml39/Ml40 Alinement Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5
3-11 . . . . . . . .M26/M27 Boresight Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5
3-12 . . . . . . . . M26A1/M27A1 Muzzle Boresight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6
3-13 . . . . . . . . M137 Telescope Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6
3-14 . . . . . . . . M145/M145A1 Telescope Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6
3-15 . . . . . . . . M149/M149E1 Telescope Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7
3-16 . . . . . . . . M187 Telescope Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8
3-17 . . . . . . . . M65 Battery Commander’s Periscope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7
3-18 . . . . . . . . M28C Tank Periscope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8
3-19 . . . . . . . . M30C Tank Periscope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8
3-20 . . . . . . . . M32E1 Head Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-9
3-21 . . . . . . . . M32E1 Daylight Body Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-10
3-22 . . . . . . . . M32E1 Passive Elbow Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-10
3-23 . . . . . . . . M36 Head Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-11
3-24 . . . . . . . . M36 Daylight Body Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-11
3-25 . . . . . . .. M36 Infrared Body Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12
3-26 . . . . . . . . M36 Passive Elbow Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12
3-27 . . . . . . . . M42 Tank Periscope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12
3-28 . . . . . . . . M42 Tank Periscope - Late Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-13
3-29 . . . . . . . . M42 Tank Periscope - Modified Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-13

iv
 *TM 750-116

LIST OF ILLUSTRATIONS – Continued

3-30 . . . . . . . . M44A Series Tank Periscope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-13

3-31 . . . . . . . . M44A Head Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-14
3-32 . . . . . . . . M44A Body Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-14
3-33 . . . . . . . . M47 Tank Periscope Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-15
3-34 . . . . . . . . M48 Periscope Body Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-15
3-35 . . . . . . . M901/M981 Tank Periscope... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-16
3-36 . . . . . . . . M14 and M14A1 Quadrants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-17
3-37 . . . . . . . . M15 Quadrant - Old Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-17
3-38 . . . . . . . . M15 Quadrant - New Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-17
3-39 . . . . . . . . M17 and M18 Quadrants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-18
3-40 . . . . . . . . Laser Rangefinder Optical Cavity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-18
3-41 . . . . . . . . Laser Rangefinder Electronics Cavity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-19
3-42 . . . . . . . . AN/VVG-2 Receiver - Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-19
3-43 . . . . . . . . AN/VVG-2 Electronics Cavity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-19
3-44 . . . . . . . . M17A1 Body Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-20
3-45 . . . . . . . . M17A1 and M17C End Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-20
3-46 . . . . . . . . M17B1C End Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21
3-47 . . . . . . . . Backup Sight, PN 12316793 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21
3-48 . . . . . . . . Integrated Sight Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21
3-49 . . . . . . . . Lamp Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-22
3-50 . . . . . . . . Commander’s Relay Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-22
3-51 . . . . . . . . Night Sight Cover Actuator Handle/Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-23
3-52 . . . . . . . . 8635466 Infinity Sight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-23
3-53 . . . . . . . . M44C Infinity Sight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24
3-54 . . . . . . . . M61 Computing Sight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24
3-55 . . . . . . . . Commander’s Extension PN 12285300 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24
3-56 . . . . . . . . Image Control Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-25
3 - 5 7 . . . . . . . . Gunner’s Auxiliary Sight PN 12278900 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-25
3-58 . . . . . . . . Gunner’s Primary Sight PN 12282140, PN 12549761-2, PN 12549761-3, PN 9377279-2 3-25
3-59 . . . . . . . . Commander’s Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26
3-60 . . . . . . . Gunner’s Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26
3-61 . . . . . . . . Head Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26
3-62 . . . . . . . . Power Converter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26
3-63 . . . . . . . . Weapon Sight PN 12279200 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27
3-64. . . . . . . . M105D Series Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27
3-65 . . . . . . . . M127 Articulated Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27
3-66 . . . . . . . . M114 Elbow Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-28
3-67 . . . . . . . . M118A2/M118A3 Elbow Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-28
3-68 . . . . . . . . M138 Elbow Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-28
3-69 . . . . . . . . M139 Elbow Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-28
3-70 . . . . . . . . M12A7Q Panoramic Telescope.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-29
3-71 . . . . . . . . M113 and M113A1 Panoramic Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-29
3-72 . . . . . . . . M115 Panoramic Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-30
3-73 . . . . . . . . M117/M117A2 Panoramic Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-30
3-74 . . . . . . . . M137 Panoramic Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-31
3-75 . . . . . . . . M137A1 Panoramic Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-31
3-76 . . . . . . . . M901A1 Panoramic Telescope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-32
3-77 . . . . . . . . M90A2 Straight Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-33
3-78 . . . . . . . . M134 Straight Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-33
3-79 . . . . . . . . Receiver/Transmitter Test Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-33
3-80 . . . . . . . . M55 Barrel Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-34
3-81 . . . . . . . . M55 Deflector Optical Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-34
3-82 . . . . . . . . Unit, Projector, Reticle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-34

v
TM 750-116

LIST OF TABLES

3-1 . . . . . . . . . Leak Test, Integrated Sight Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-22

3-2 . . . . . . . . . Leak Test, Commander’s Relay Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-23

vi
 TM 750-116

CHAPTER 1
INTRODUCTION

SECTION I
GENERAL INFORMATION
1-1. SCOPE. This manual provides general instruc- 1-4. REPORTING EQUIPMENT
tions for purging and charging fire control instruments with IMPROVEMENT RECOMMENDATIONS
dry nitrogen. If specific instructions are provided in a tech- (EIR). If the equipment used in these procedures needs
nical publication pertaining to a specific fire control item, improvement, let us know. Send us an EIR. You, the user,
this publication does not attempt to take precedence over are the only one who can tell us what you do not like about
that publication. your equipment. Let us know what you do not like about
1-2. MAINTENANCE FORMS, RE- the design or performance. Put it on an SF 368 (Quality
CORDS, AND REPORTS. Department of the Deficiency Report). Mail it to us at Commander, U.S.
Army forms and procedures used for equipment mainte- Army Armament, Munitions and Chemical Command,
nance will be those prescribed by DA PAM 738-750, The ATTN: AMSMC-QAD, Rock Island, IL 61299-6000.
Army Maintenance Management System. We will send you a reply.

1-3. DESTRUCTION OF ARMY MATERl-

ALS TO PREVENT ENEMY USE. Refer to
TM 750-244-3 and TM 750-244-1-4 for procedures con-
cerning the destruction of this material.

SECTION II
EQUIPMENT DESCRIPTION AND DATA
1-5. EQUIPMENT CHARACTERISTICS, 1-6. SAFETY, CARE, AND HANDLING.
CAPABILITIES, AND FEATURES. The following safety precautions are listed for the protec-
tion of personnel performing the procedures contained in
a. Port Identification. Purging and charging ports of this manual.
new production and overhauled fire control instruments are a. First Aid. Serious injury may occur at any time
color coded. The color code system provides for painting during the performance of these procedures. Prior to per-
of a gray band around the inlet port and a yellow band forming the work requirements, personnel should familiar-
around the outlet port. ize themselves with first aid information contained in
b. Port Location. Illustrations for fire control instru- FM21-11.
ments that are purged and charged in this manual are in- b. Compressed Gas. Compressed nitrogen gas is
cluded to show the location of inlet and outlet ports as well used for purging and charging. Death or severe injury may
as associated hardware. result if personnel fail to observe safety precautions.

1-1
TM 750-116

(3) Emergency Procedures. If a tritium source

breaks, inform other personnel to vacate the area or move
upwind. If skin contact is made with any area contaminated
with tritium, wash immediately with nonabrasive soap and
water. Report the incident to the local RPO. Actions below
will be taken under supervision or direction of the local
RPO.
(a) Personnel handling the instrument should wear
rubber or latex gloves. Instrument must be immediately
double wrapped in plastic (item 1, appx B), sealed, pack-
aged and evacuated to depot. Outside package must be
identified as "Broken Tritium Device - Do Not Open."
Dispose of used gloves as radioactive waste per instructions
from local RPO and wash hands well.
HANDLE WITH CARE. IN THE (b) Personnel who may have handled the broken
EVENT THE RADIOLUMINOUS SOURCE tritium instrument should report to health clinic for tritium
IS BROKEN, CRACKED, OR SUDDENLY bioassay. Optimum bioassay sample is at least four hours
LOSES ILLUMINATION, DO NOT AT- after exposure.
TEMPT TO REPAIR. IMMEDIATELY
DOUBLE WRAP INSTRUMENT IN PLAS- (c) Broken tritium sources indoors may result in
TIC AND NOTIFY THE LOCAL RADI- tritium contamination in the area, such as workbench or
ATION PROTECTION OFFICER (RPO). table. The area must be cordoned off, restricted until wipe
CONTACT THE BASE SAFETY OFFICE tests indicate no contamination.
FOR THE NAME AND TELEPHONE (4) Further Information.
NUMBER OF YOUR LOCAL RPO: (a) Requirements for safe handling, maintenance,
LOCAL RPO: storage and training are located in TM 9-254, General
TELEPHONE: Maintenance Procedures for Fire Control Materiel.
(b) If assistance is needed, contact your local or ma-
(1) Safety Procedures for Nuclear Regulatory jor command (MACOM) safety office(s) for information on
safe handling, shipping, storage, maintenance, or disposal
Commission (NRC) Licensed Tritium Fire Control
of radioactive instruments.
Devices.
(c) The licensee/AMCCOM RPO may be contacted
(a) Purpose: To implement mandatory license re- by writing to Commander, U.S. Army Armament, Muni-
quirements for use and maintenance of tritium radiolumi- tions and Chemical Command (AMCCOM), ATTN:
nous fire control instruments used on howitzers, mortars, AMSMC-SFS, Rock Island, IL 61299-6000, or telephone:
tanks, and rifles. DSN 793-2965/2995, Commercial (309) 782-2965/2995,
(b) Scope: This procedure is applicable to all person- Fax extension 2289, E-Mail SFO1@RIA-
nel working with tritium devices, including organizational, EMH1.ARMY.MIL. After work hours, the AMCCOM
direct support, general support maintenance and operator RPO may be contacted through the staff duty office at DSN
levels. 793-6001, Commercial (309) 782-6001.
(c) Radiological Hazard: The beta radiation 1-7. CORROSION PREVENTION AND
emitted by tritium presents no external radiation hazard. CONTROL (CPC). Corrosion Prevention and Control
However, if taken internally, it can damge soft tissue. If a (CPC) of Army materiel is a continuing concern. It is im-
capsule is broken, the tritium gas will dissipate into the sur- portant that any corrosion problems with these items be
rounding air and surfaces near the vicinity of the break may reported so that the problem can be corrected and improve-
become contaminated. Tritium can be taken into the body ments can be made to prevent the problem in future items.
by inhalation, ingestion, or percutaneous (skin) absorption/ While corrosion is typically associated with rusting of met-
injection. als, it can also include deterioration of other materials such
(2) Safety Precautions. as rubber and plastic. Unusual cracking, softening, swell-
ing, or breaking of these materials may be a corrosion prob-
(a) Check for illumination in low light or darkroom lem. If a corrosion problem is identified, it can be reported
prior to use or service. If not illuminated, do not repair.
using Standard Form 368, Product Quality Deficiency Re-
Double wrap the entire instrument in plastic (item 1, appx port. Use of key words such as “corrosion,” “rust,” “deteri-
B) and notify the local RPO. oration,” or “cracking” will assure that the information is
(b) Removal of the radioluminous source from the identified as a CPC problem. The form should be submitted
instrument is prohibited except at authorized depots. No to: Commander, U.S. Army Armament, Munitions and
eating, drinking, smoking or applying cosmetics will be Chemical Command, ATTN: AMSMC-QAD/Customer
allowed in tritium device work areas. Feedback Center, Rock Island, IL 61299-6000.

1-2
 TM 750-116

CHAPTER 2
GENERAL PROCEDURES

2-1. SCOPE. This chapter describes genera!

procedures for the setup of purging and charging
equipment time cycles.

2-2. SETUP OF PURGING AND CHARGING DO NOT DROP TANK OF COMPRESSED

EQUIPMENT, (figs. 2-1 and 2-2). NITROGEN GAS. WHEN USING IN CONFINED
AREAS, USE EXTREME CARE;
a. Setup for Single Stage Fixture(fig. 2-1) GAS COULD CAUSE ASPHYXIATION.

(2) Securely attach regulator to tank valve using ap-

propriate adapter supplied with purging kit if
necessary.

(3) Securely attach hose assembly to the adapter.

NOTE
When using regulator 11729749, adapter
10917072-2 is required to connect hose assembly to
low pressure to low pressure port of regulator.
Figure 2-1.
(4) Close pressure regulator valve
counterclockwise (CCW) to the extreme closed
position.

(5) Open the nitrogen tank valve (CCW) slowly until

the maximum tank pressure is registered on the high
pressure gage.
NOTE
If pressure indicated is less than 100 psi, obtain
and use replacement tank.

(6) SIowly open pressure regulator valve clockwise

(1) Obtain a tank of water pumped dry nitrogen and (CCW) until approximately 5 psi is registered on the low
remove threaded protective cover from the outlet of the pressure gage. Check for and eliminate any
tank. Open tank valve momentarily to rid valve seat of interference; close pressure regulator valve (CCW).
any foreign material.
(7) For bleed down procedures, refer to para 2-3a.
(1.1) Remove the adapter from the regulator
install tee into the regulator. Install valve relief into
tee in the 3 o’clock position. install the adapter into
tee in the 6 o’clock position.

Change 1 2-1
TM 750–116

b. Setup for Two Stage Fixture (fig. 2–2). (7) Open test fixture valve(s) until test fixture gage(s)
indicate(s) proper pressure.
(8) Close manifold valve(s) and check pressure read-
ing on test fixture gage(s) .
(9) Remove stopper(s) from outlet pipe(s). Open
manifold valve(s) and check the pressure on test fixture
gage(s). Adjust fixture valve(s) if necessary.
(10) Close manifold valve(s) and attach feeder tube(s)
to outlet pipe(s).
(11) For bleed down procedures, refer to para 2-3.b.

2-3. BLEED DOWN OF PURGING AND

CHARGING EQUIPMENT (fig. 2-1 and
2-2).

DO NOT REMOVE REGULATOR ASSEM-

BLY, ADAPTER, OR HOSE BEFORE
FIRST PERFORMING ENTIRE BLEED
DOWN PROCEDURE. INJURY COULD
RESULT FROM SUDDEN RELEASE OF
HIGH PRESSURE GAS.
a. Bleed Down for Single Stage Fixture (fig.
Figure 2–2 Setup for Two–Stage Fixture, 2–1).
PN 8565556
(1) Close pressure regulator valve counterclockwise
(CCW).
(1) Place a tank of dry nitrogen in a vertical position (2) Close tank valve clockwise (CW).
in the back of the fixture so that the tank is lodged in the
structural steel “V” formation of the fixture and secure with (3) Slowly open pressure regulator valve (CW) until
the strap and clamping screw arrangement provided. low pressure gage and high pressure gage both indicate
zero.
(2) Secure regulator assembly to the tank. Make cer-
tain pressure regulator valve is turned counterclockwise (4) Close pressure regulator valve (CCW).
(CCW) to off. Open nitrogen tank valve (CCW) until max-
imum tank pressure is registered on the high pressure gage.
NOTE
Pressure regulator valve should be left in the
If pressure indicated is less than 100 psi, obtain closed position when not in use. Leaving
and use a replacement tank. valve in the open position could damage
regulator diaphragm.
(3) Connect hose assembly to regulator assembly.
Open manifold valve. b. Bleed Down for Two Stage Fixture (fig. 2-2).
(1) Close pressure regulator valve and test fixture
valve(s) counterclockwise (CCW).
(2) Close tank valve clockwise (CW).
At no time should the pressure be permitted (3) Open transfer valve by pulling it to the outermost
to exceed 15 psi. Pressure greater than 15 psi position.
could damage the unit.
(4) Rotate pressure regulator valve CW until low pres-
(4) Open transfer valve by pulling it to the outermost sure gage indicates 15 psi.
position.
(5) With manifold valve(s) open, slowly rotate test
(5) Close test fixture valve(s) and ensure low pressure fixture valve(s) CW until low pressure gage, high pressure
gage indicates 0 psi. gage and test fixture gage(s) indicate zero.
(6) Open pressure regulator valve clockwise (CW) (6) Close pressure regulator valve and test fixture
until low pressure gage indicates 15 psi. valve(s) CCW.

2-2
 TM 750-116

2-5. PURGING AND CHARGING PROCE-

DURES.
a. Purge and Charge: Inlet Port Entry, Relief
Pressure regulator valve and test fixture
Valve Exit. This procedure is used when instrument is
valve(s) should be left in the closed position
designed to hold a charge.
when not in use. Leaving valves open could
result in damage to unit diaphragms.

2-4. TIME CYCLES.

a. Maintenance personnel will purge and charge tank
fire control items every 180 days and artillery fire control
items every 90 days or when condensation is evident in the
instrument.
NOTE
The 180-day cycle does not apply to rangefinders
which are purged and charged once a year. How-
ever, a visual inspection is required every 90 days
for evidence of moisture. The electrical compo-
nents of M21 Ballistic Computer System to in- HANDLE WITH CARE. IN THE EVENT
clude the Ammo Select Unit, Cant Angle Sensor, THE RADIOLUMINOUS SOURCE IS
Computer Unit, Output Unit and Rate Tachome- BROKEN, CRACKED, OR SUDDENLY
ter and the Laser Rangefinder, AN/VVG–2, Elec- LOSES ILLUMINATION, DO NOT AT-
tronics Unit require purging every 180 days, TEMPT TO REPAIR. IMMEDIATELY
when unit is opened for maintenance, or when ev- WRAP DEVICE IN PLASTIC AND
idence of moisture is present. NOTIFY THE LOCAL RADIATION PRO-
TECTION OFFICER (RPO).
b. Maintenance personnel will purge and charge fire (1) Remove inlet port cap of instrument to be purged
control materiel being repaired whenever the repair func- and charged.
tion affects internal sealing.
(2) Inspect inlet port for cleanliness and presence of
c. For maintenance of material in storage refer to appli- valve core. Remove any dirt or foreign matter.
cable equipment manuals.

d. NSN’s 4820-01-384-9005 and 4730-00-277-9615

are mandatory for purging artillery fire control. Ensure regulator valve is closed (counter-
clockwise - CCW) or damage may occur to
regulator.

To avoid damage to instruments being

purged and charged, do not exceed maxi-
mum pressure. Unless otherwise noted for
specific instrument, maximum pressure is 10
psi.
(3) Connect hose assembly to inlet pert on instrument.
(4) Open main valve on nitrogen tank (CCW).
(5) Open regulator valve (clockwise - CW) until spe-
cified purge pressure is indicated on low pressure gage.
(6) Watch low pressure gage and listen for purge relief
valve to open.
(a) Relief valve should open between specified
pressures.
(b) If relief valve does not open before pressure
reaches maximum range, immediately turn off regulator
valve (CCW). Replace pressure relief valve on instrument.
Repeat procedure.

Change 1 2-3
TM 750–116

(7) Purge instrument for specified time. If moisture b. Purge and Charge - Inlet Port Entry, Outlet
is still present, a longer purge time may be required. Port Screw(s) This procedure is used when instrument
(8) Close the regulator valve (CCW). is designed to hold a charge.
(9) Watch low pressure gage and listen for purge re-
lief valve to close.
(a) Relief valve should close at specified pressure.
(b) If pressure relief valve does not close before
reaching the lowest pressure indicated, replace the pressure
relief valve and repeat procedure.
(10) Leak test by allowing instrument to stand for
specified time.
(a) Watch low pressure gage for indication of nitro-
gen leaks. (Low pressure gage will indicate decreasing
pressure.) If no leak is indicated, go to step 11.
(b) If pressure reduces, perform leak check: HANDLE WITH CARE. IN THE EVENT
THE RADIOLUMINOUS SOURCE IS
— Apply a soap solution to all sealed joints and BROKEN, CRACKED, OR SUDDENLY
screws. LOSES ILLUMINATION, DO NOT AT-
— Open regulator valve (CW) until specified TEMPT TO REPAIR. IMMEDIATELY
pressure registers on low pressure gage. WRAP DEVICE IN PLASTIC AND
— When pressure relief valve opens, close regu- NOTIFY THE LOCAL RADIATION PRO-
lator valve (CCW). TECTION OFFICER (RPO).
(1) Remove inlet port cap of instrument to be purged
— Watch for bubbles to appear around seals and and charged.
screws.
(2) Inspect valve stem for cleanliness and presence of
— Refer to appropriate maintenance manuals to valve core. Remove any dirt or foreign matter.
replace defective seals.
— When defective seals are replaced, repeat
purge and charge procedure.
Ensure regulator valve is closed (counter-
(11) If no leaks are found on instrument, perform leak
test on purge kit and hose connection while still connected clockwise - (CCW) or damage may occur to
regulator.
to instrument. Repeat procedure until all leaks are elimi-
nated.
(12) Remove hose assembly.
(13) Close main tank valve (CW). Apply soap solu- To avoid damage to instruments being
tion to the valve core. If a Ieak is found, replace valve core purged and charged, do not exceed maxi-
of instrument and repeat purge and charge procedure. mum pressure. Unless otherwise noted for
(14) Install inlet port cap on instrument. specific instrument, maximum pressure is 10
psi.
(15) For bleed down procedures, refer to para 2-3. (3) Connect hose assembly to valve stem on instru-
ment.
(4) Open main valve on nitrogen tank (CCW).
(5) Remove outlet port screw(s) (unless otherwise
directed for specific instrument) and any accompanying
gasket/preformed packing.
(6) Open regulator valve clockwise (CW) until speci-
fied purge pressure is indicated on low pressure gage.
(7) Watch low pressure gage and listen for gas escap-
ing from outlet port. Do not allow pressure to exceed maxi-
mum specified pressure.
(8) Purge instrument for specified time. If moisture
is still present, a longer purge time may be required.
(9) Reduce pressure to 1 psi.

2-4
 TM 750-116

(10) Check outlet port screw to ensure seal on screw c. Purge Only, Inlet Port Entry, Outlet Port
is serviceable. Replace self-sealing screw if necessary. If Screw. This procedure is used when instrument does not
other than self-sealing screw is used, sealing compound, hold a charge.
(item 6, appx B, unless otherwise specified) must be applied
to screw before installing.
(11) Install outlet port screw(s) and any accompany-
ing gasket/preformed packing.
(12) Increase pressure to specified charge pressure for
specified time.
(13) Close regulator valve (CCW).
(14) Leak test by allowing instrument to stand for
specified time.
(a) Watch low pressure gage for indication of nitro-
gen leaks (low pressure gage will indicate decreasing pres-
sure). If no leaks occur, proceed to step 15. HANDLE WITH CARE. IN THE EVENT
(b) If pressure reduces, perform leak check: THE RADIOLUMINOUS SOURCE IS
BROKEN, CRACKED, OR SUDDENLY
- Apply a soap solution to all sealed joints and
LOSES ILLUMINATION, DO NOT AT-
screws.
TEMPT TO REPAIR. IMMEDIATELY
- Open regulator valve (CW) to increase internal DOUBLE WRAP INSTRUMENT IN PLAS-
pressure to instrument’s charge pressure. TIC AND NOTIFY THE LOCAL RADI-
- Close regulator valve (CCW). ATION PROTECTION OFFICER (RPO).
- Watch for bubbles to appear around seals and (1) Remove inlet port cap from instrument to be
screws. purged.
(2) Inspect inlet port for cleanliness and presence of
- Refer to appropriate maintenance manuals to valve core. Remove any dirt or foreign matter.
replace defective seals.
- When defective seals are replaced, repeat
purge and charge procedure.
(15) If no leaks are found on the instrument, perform Ensure regulator valve is closed (counter-
a leak test on the purge kit and hose connection while still clockwise - CCW) or damage may occur to
connected to the equipment. Repeat procedure until all regulator.
leaks are eliminated.
(16) Remove hose assembly.
(17) Close main tank valve (CW). Apply soap solu- To avoid damage to instruments being
tion to valve core. If a leak is found, replace valve core of purged, do not exceed maximum pressure.
instrument and repeat purge and charge procedure. Unless otherwise noted for specific instru-
(18) Install inlet port cap on instrument. ment, maximum pressure is 10 psi.
(19) For bleed down procedures, refer to para 2-3. (3) Connect hose assembly to inlet port valve stem on
instrument.
(4) Open main valve on nitrogen tank (CCW).
(5) Remove outlet port screw (unless otherwise di-
rected for specific instrument) with any accompanying gas-
ket/preformed packing.
(6) Open regulator valve (clockwise - CW) until spe-
cified purge pressure is indicated on low pressure gage.
(7) Watch low pressure gage and listen for gas escap-
ing from outlet port. Do not allow pressure to exceed maxi-
mum specified pressure.
(8) Purge instrument for specified time. If moisture is
still present, a longer purge time may be required.
(9) Close the regulator valve (CCW).

2-5
TM 750-116

(10) Check outlet port screw to ensure seal on screw

is serviceable. Replace self-sealing screw if necessary. If
other than self-sealing screw is used, sealing compound
(item 6, appx B, unless otherwise specified) must be applied Ensure regulator valve is closed (counter-
to screw before installing. clockwise - CCW) or damage may occur to
regulator.
(11) Install outlet port screw with any accompanying
gasket/preformed packing.
(12) Remove hose assembly.
(13) Install inlet port cap. To avoid damage to instruments being
purged, do not exceed maximum pressure.
(14) For bleed down procedures, refer to para 2-3. Unless otherwise noted for specific instru-
d. Purge Only - Inlet Port Screw, Outlet Port ment, maximum pressure is 10 psi.
Screw(s). This procedure is used when instrument does (3) Install specified purge adapter in inlet port.
not hold a charge.
(4) Connect hose assembly to purge adapter on the
instrument.
(5) Open main valve on nitrogen tank (CCW).
(6) Remove outlet screw(s) (unless otherwise directed
for specific instrument) and any accompanying gasket/pre-
formed packing.
(7) Open regulator valve (clockwise - CW) until
specified purge pressure is indicated on low pressure gage.
(8) Watch low pressure gage and listen for gas escap-
ing from outlet port(s). (Do not allow pressure to exceed
maximum specified pressure.
(9) Purge instrument for specified time. If moisture is
still present, a longer purge time may be required.
HANDLE WITH CARE. IN THE EVENT (10) Close the regulator valve (CCW).
THE RADIOLUMINOUS SOURCE IS
BROKEN, CRACKED, OR SUDDENLY (11) Check inlet and outlet port screws to ensure
LOSES ILLUMINATION, DO NOT AT- seals on screws are serviceable. Replace self-sealing
TEMPT TO REPAIR. IMMEDIATELY screws if necessary. (If other than self-sealing screws are
DOUBLE WRAP INSTRUMENT IN PLAS- used, sealing compound (item 6, appx B, unless otherwise
TIC AND NOTIFY THE LOCAL RADI- specified) must be applied to screw before installing.
ATION PROTECTION OFFICER (RPO). (12) Install outlet screw(s) and any accompanying
gasket/preformed packing (if required).
(1) Remove inlet port screw from instrument to be
purged. (13) Remove hose assembly and adapter.
(2) Inspect inlet port for cleanliness. Remove any dirt (14) Install inlet screw.
or foreign matter. (15) For bleed down procedures, refer to para 2-3.

2-6
 TM 750-116

CHAPTER 3
PURGING AND CHARGING SPECIFIC INSTRUMENTS

SECTION I
GENERAL INFORMATION
3-1. SCOPE.
a. This chapter presents purging, charging, and leak
testing pressures and times for specific fire control instru-
ments. Refer to paragraph 2-2 for initial setup information
and paragraph 2-5 for general purging and charging proce-
dures.
b. Also included are instructions for separation of ma-
jor assemblies, leak checking pressures, time durations, use
of inlet port adapters, and any specific notes, cautions or
warnings applicable to the specific instrument. Each proce-
dure refers to a partially exploded illustration showing loca-
tion of inlet and outlet ports.
c. For presentation purposes, specific instrument proce- HANDLE WITH CARE. IN THE EVENT
dures are arranged in categories: Aiming Circle, Alinement THE RADIOLUMINOUS SOURCE IS
Devices, Binoculars, Collimators, Computers, Mounts, BROKEN, CRACKED, OR SUDDENLY
Periscopes, Quadrants, Rangefinders, Sights, Telescopes, LOSES ILLUMINATION, DO NOT AT-
and Reticle Projector Unit. Under each of these categories TEMPT TO REPAIR. IMMEDIATELY
the specific instruments are listed alphanumerically. DOUBLE WRAP INSTRUMENT IN PLAS-
TIC AND NOTIFY THE LOCAL RADI-
ATION PROTECTION OFFICER (RPO).

NOTE
If the outlet port screw or purging inlet screw is
lost or damaged, replace with the appropriate
screw as listed in Appendix C or in appropriate
technical manual.
The soap solution used in general procedures in
chapter 2 is a mixture of soap (item 7, appx B) and
water. Leak-Tee may also be used if available.

3-1
TM 750-116

SECTION II
SPECIFIC INSTRUMENTS
g. Purge instrument at 5 psig for 5 minutes.
h. Remove adapter assembly and install self-sealing
DO NOT EXCEED THE PRESSURES IN- screw (2).
DICATED THROUGHOUT THE FOL- i. Elevate elbow telescope to about 800 mils.
LOWING PROCEDURES.
j. Install self-sealing screw (1).

3-2. AIMING CIRCLE, M2A2 (fig. 3-1). k. Return elbow telescope to zero mils.

SELF-SEALING SELF-SEALING
SCREW SCREW
3-3. BINOCULAR, M19 (fig. 3-2)

NOTE
Both sides of the binocular must be purged indi-
vidually. Repeat procedure para 2-5.d. for both
sides.

Figure 3-1 M2A2 Aiming Circle

a. Perform purging procedure para 2-5.d.

b. Depress elbow telescope to about 400 mils.
c. Remove self-sealing screw (1).
d. Elevate elbow telescope until self-sealing screw (2)
is accessible.
e. Remove self-sealing screw (2).
NOTE
On aiming circle with only one self-sealing Figure 3-2 M19 Binocular
screw, remove one of the reticle setscrews to
purge. Apply sealing compound (item 6, appx B)
to setscrew to reinstall.
a. Perform purging procedure para 2-5.d.
f. Install adapter assembly with 8-32 UNC-2A
threads. b. Purge instrument at 5 psig for 5 minutes.

3-2
 TM 750-116

3-4. COLLIMATOR, M1A1 (fig. 3-3). NOTE

For sealing the collimator, the two stage fixture
is required (refer to para 2-2.b.). For regular
purging and charging, the single stage fixture may
be used (refer to para 2-2.a.).
a. Perform purging and charging procedure para 2-5.b.
b. Purge instrument at 3 psig for 5 minutes.
c. Check to be sure nitrogen is escaping from both out-
let ports.
d. Charge instrument at 3 psig maintaining pressure for
10 seconds.
e. Leak test for a minimum of 5 minutes.
f. Remove hose assembly and release all pressure by
HANDLE WITH CARE. IN THE EVENT depressing inlet port valve stem.
THE RADIOLUMINOUS SOURCE IS g. Reconnect hose assembly and charge instrument at 1
BROKEN, CRACKED, OR SUDDENLY psig for 10 seconds.
LOSES ILLUMINATION, DO NOT AT-
h. Install inlet port cap.
TEMPT TO REPAIR. IMMEDIATELY
DOUBLE WRAP INSTRUMENT IN PLAS- 3-5. COMPUTER, M21 ELECTRONIC
TIC AND NOTIFY THE LOCAL RADI-
ATION PROTECTION OFFICER (RPO).
(figs. 3-4 through 3-9).

a. Ammo Select Unit - two each (fig. 3-4).

...... \

Figure 3-4 Ammo Select Unit

Figure 3-3 M1A1 Collimator (1) Perform purging and charging procedure para
2-5.b.
NOTE (2) Purge each unit at 8 psig for 5 minutes.
Actual location of outlet port screws may vary (3) Charge each unit at 1 psig maintaining pressure
from location shown in illustration due to coli- for 10 seconds.
mator adjustments. (4) Leak test for a minimum of 5 minutes.

3-3
TM 750-116

b. Cant Angle Sensor (fig. 3-5). Refer to para d. Gunner’s Control Unit (fig. 3-7). Refer to
3-5.a for procedures. para 3-5.a. for procedures.

Figure 3-5 Cant Angle Sensor

c. Computer Unit (fig 3-6). Refer to para 3-5.a.

for procedures.

Figure 3-7 Gunner’s Control Unit

e. Output Unit (fig. 3-8). Refer to para 3-5.a. for

procedures.

Figure 3-6 Computer Unit

Figure 3-8 Output Unit

3-4
 TM 750-116

f. Rate Tachometer (fig. 3-9). Refer to para 3-5.a.

for procedures.

Figure 3-10 M139/M140 Alinement Device

Figure 3-9 Rate Tachometer a. Perform purging and charging procedure para
2-5.b.
b. Purge instrument at 7 psig for 5 minutes.
c. Charge instrument at 1 psig maintaining pressure
3-6. DEVICE, ALINEMENT, M139/M140, for 10 seconds.
(fig. 3-10). d. Leak test for minimum of 5 minutes.
3-7. DEVICES, BORESIGHT.
a. M26/M27 Boresight (fig. 3-11).

HANDLE WITH CARE. IN THE EVENT

THE RADIOLUMINOUS SOURCE IS
BROKEN, CRACKED, OR SUDDENLY
LOSES ILLUMINATION, DO NOT AT-
TEMPT TO REPAIR. IMMEDIATELY
DOUBLE WRAP INSTRUMENT IN PLAS- Figure 3-11 M26/M27 Boresight Device
TIC AND NOTIFY THE LOCAL RADI-
ATION PROTECTION OFFICER (RPO). (1) Remove the rubber protective head cover.

3-5
 TM 750-116

NOTE 3-8. MOUNTS, TELESCOPE.

Some early manufacture boresight inlet ports
a. Telescope Mount, M137 (fig. 3-13).
were equipped with metric threads. To attach the
hose asembly to these units, it is necessary to use
the 10-32 adapter supplied with the purging kit.
Insert the adapter carefully and do not force the
adapter past its binding point.
(2) Perform purging procedure para 2-5.d.
(3) Purge instrument at 5 psig for 5 minutes.
(4) Install the rubber protective head cover on the
boresight.

b. M26A1/M27A1 Muzzle Boresight (fig. 3-12).

Figure 3-13 M137 Telescope Mount

(1) Perform purging procedure para 2-5.c.

(2) Purge instrument at 5 psig for 5 minutes.

b. Telescope Mount, M145/M145A1 (fig. 3-14).

Figure 3-12 M26A1/M27A1 Muzzle Boresight

(1) Release pressure from optical unit by removing

pneumatic inlet port cap and depressing valve core .
(2) Attach hose assembly to angle valve (special tool,
TM9-4933-259-14&P) and install angle valve on inlet
port.
(3) Turn angle valve T clockwise (CW) until snug.
(4) Perform purging and charging procedure para
2-5.b.
(5) Purge instrument at 5 psig for 5 minutes or until
all traces of moisture in optical unit are removed.
(6) Charge instrument at 3 psig maintaining pressure
for 10 seconds.
Figure 3-14 M145/M145A1 Telescope Mount
(7) Turn angle valve T counterclockwise (CCW) until
snug.
(8) Remove hose assembly and angle valve from inlet
(1) Perform purging procedure para 2-5.c.
port core.
(9) Leak test for minimum of 5 minutes. (2) Purge instrument at 5 psig for 5 minutes.

3-6
 TM 750-116

c. Telescope Mount, M149/M149E1 (fig. 3-15). d. Telescope, Mount, M187 (fig. 3-16).

NOTE

Mount must be removed from installed position

for purging and charging operations. Refer to ap-
pendix A for a listing of applicable publications.

HANDLE WITH CARE. IN THE EVENT

THE RADIOLUMINOUS SOURCE IS
BROKEN, CRACKED, OR SUDDENLY
LOSES ILLUMINATION, DO NOT AT-
TEMPT TO REPAIR. IMMEDIATELY
DOUBLE WRAP INSTRUMENT IN PLAS-
TIC AND NOTIFY THE LOCAL RADI-
ATION PROTECTION OFFICER (RPO).

Figure 3-15 M149/M149E1 Telescope Mount

(1) Remove inlet port cap and outlet screw on M149

Telescope Mount. Do not remove poppet valve on M149E1
Telescope Mount.

(2) Perform purging and charging procedure para

2-5.b for M149 and para 2-5.a for M149A1.

(3) Purge M149 Telescope Mount at 5 psig and

M149E1 Telescope Mount at 3 psig. Maintain pressure for
10 minutes.
Figure 3-16 M187 Telescope Mount
(4) Charge instrument at 1 psig for 40 seconds.
(1) Perform purging and charging procedure para
(5) Leak test for a minimum of 5 minutes. 2-5.a.
(2) Relief valve should open between 3-10 psig.
(3) Purge instrument for 5 minutes.
(4) Relief valve should close between 1-5 psig.
(5) Leak test for minimum of 5 minutes.

3-7
TM 750-116

3-9. PERISCOPE, M65 BATTERY COM-

MANDER’S (fig. 3-17).
NOTE

Both tubes of the Battery Commander’s Peri-

scope must be purged and charged separately. Re-
peat procedure for each tube assembly.

Ensure that nitrogen is escaping from both outlet

ports before proceeding with charging proce-
dures.

Figure 3-18 M28C Tank Periscope

(1) Perform purging and charging procedure para

2-5.b.
(2) Purge instrument at 5 psig for 10 minutes.
(3) Charge instrument at 1 psig maintaining pressure
for 10 seconds.
(4) Leak test for minimum of 5 minutes.
b. Periscope, M30C Tank (fig. 3-19).
NOTE
The periscope must be removed from installed
position for purging and charging operations.
Refer to appendix A for a listing of applicable
publications.
Figure 3-17 M65 Battery Commander’s Periscope

a. Perform purging and charging procedure para 2-5.b.

b. Purge instrument at 5 psig for 10 minutes.

c. Charge instrument at 1 psig maintaining pressure for

20 seconds.

d. Leak test for minimum of 5 minutes.

3-10. PERISCOPES, TANK.

a. Periscope, M28C Tank (fig. 3-18).

NOTE

The eyeshield must be removed to provide access

to outlet screw. Figure 3-19 M30C Tank Periscope

3-8
 TM 750-116

(1) Perform purging and charging procedure para (1) Head Assembly (fig. 3-20).
2-5.b.
(2) Purge instrument at 5 psig for 10 minutes.
(3) Charge instrument at 1 psig maintaining pressure
for 20 seconds.
(4) Leak test for minimum of 5 minutes.
c. Periscope, M32E1 Tank (figs. 3-20 through
3-22).

ENSURE THAT 1.5V-OFF-24V SWITCH

ON BOTTOM OF THE INFRARED BODY
ASSEMBLY IS SET TO OFF; THIS UNIT
CARRIES 16,000 VDC.

Do not purge and charge the infrared body

assembly in bright light; prolonged exposure Figure 3-20 M32E1 Head Assembly
can cause damage to the image conversion
tube. (a) Perform purging and charging procedure para
2-5.b.
NOTE
(b) Purge instrument at 8 psig for 5 minutes.
Periscope must be removed from installed posi-
tion for purging and charging operations. Refer (c) Charge instrument at 1 psig maintaining pressure
to appendix A for listing of applicable public a- for 10 seconds.
(d) Leak test for minimum of 5 minutes.

3-9
TM 750-116

(2) Daylight Body Assembly (fig. 3-21). (3) Passive Elbow Assembly (fig. 3-22).
NOTE
NOTE
The passive elbow assembly must be removed
The daylight body assembly must be removed from head assembly for purging and charging
from head assembly for purging and charging operations. Refer to appendix A for a listing of
operations. Refer to appendix A for a listing of applicable publications.
applicable publications.

NOTE: TWO VIEWS SHOWN FOR CLARITY

Figure 3-22 M32E1 Passive Elbow Assembly

(a) Perform purging and charging procedure para

Figure 3-21 M32E1 Daylight Body Assembly 2-5.b.
(b) Purge instrument at 8 psig for 5 minutes.
(c) Charge instrument at 1 psig maintaining pressure
for 20 seconds.
(a) Perform purging and charging procedure para
2-5.b. (d) Leak test for minimum of 5 minutes.

(b) Purge instrument at 8 psig for 5 minutes. d. Periscope, M32CE1 Tank (figs. 3-20 through
3-22. Refer to para 3-10.c. for procedures.
(c) Charge instrument at 1 psig maintaining pressure
for 20 seconds.
e. Periscope, M35E1 Tank (figs. 3-20 through
(d) Leak test for a minimum of 5 minutes. 3-22). Refer to para 3-10.c. for procedures.

3-10
 TM 750-116

f. Periscope, M36 Tank (figs. 3-23 through (2) Daylight Body Assembly (fig. 3-24).
3-26).
NOTE
The daylight body assembly and the infrared
body assembly must be removed from the head
ENSURE THAT 1.5-OFF-24V SWITCH assembly for purging and charging procedures.
ON THE BOTTOM OF THE INFRARED Refer to appendix A for a listing of applicable
BODY ASSEMBLY IS SET TO OFF; THIS publications.
UNIT CARRIES 16,000 VDC.

Do not purge and charge the infrared body

assembly in bright light; prolonged exposure
can cause damage to the image conversion
tube.
NOTE
The periscope must be removed from the in-
stalled position for purging and charging opera-
tions. Refer to appendix A for a listing of
applicable publications.
(1) Head Assembly (fig. 3-23).

Figure 3-24 M36 Daylight Body Assembly

Figure 3-23 M36 Head Assembly

(a) Perform purging and charging procedure para
2-5.b.
(a) Perform purging and charging procedure para
2-5.b. (b) Purge instrument at 8 psig for 5 minutes.
(b) Purge instrument at 8 psig for 5 minutes.
(C) Charge instrument at 1 psig for 20 seconds.
(c) Charge instrument at 1 psig for 10 seconds.
(d) Leak test for minimum of 5 minutes. (d) Leak test for a minimum of 5 minutes.

3-11
TM 750-116

(3) Infrared Body Assembly (fig. 3-25). (4) Passive Elbow Assembly (fig. 3-26). Re-
NOTE fer to para 3-10.f.(3) for procedures.
The infrared body assembly must be removed
from the head assembly for purging and charg-
ing operations. Refer to appendix A for a list-
ing of applicable publications.

NOTE: TWO VIEWS SHOWN FOR CLARITY

Figure 3-26 M36 Passive Elbow Assembly

NOTE: TWO VIEWS SHOWN FOR CLARITY
g. Periscope, M36E1 Tank (figs. 3-23 through
Figure 3-25 M36 Infrared Body Assembly 3-26). Refer to para 3-10.f. for procedures.
h. Tank Periscope, M42 Tank (fig. 3-27).
(a) Perform purging and charging procedure para NOTE
2-5.b. Early, later, and modified production periscopes
(b) Purge instrument at 8 psig for 5 minutes. must be removed for purging and charging pro-
(c) Charge instrument at 1 psig for 20 seconds. cedures. Refer to appendix A for a listing of
applicable publications.
(d) Leak test for a minimum of 5 minutes. (1) Early Production (fig. 3-27).

Figure 3-27 M42 Tank Periscope - Early Production

(a) Perform purging procedure para 2-5.d.
(b) Purge instrument at 5 psig for 5 minutes.

3-12
 TM 750-116

(2) Late Production (fig. 3-28). i. Periscope, M44A Tank (figs. 3-30 through
3-32.

ENSURE THAT THE VEHICLE MASTER

SWITCH AND THE PERISCOPE EMER-
GENCY SWITCH ARE IN THE OFF POSI-
TION. THE HIGH VOLTAGE AND LOW
AMPERAGE OF THE POWER PACK IS
NOT DANGEROUS; HOWEVER, IF THE
HIGH VOLTAGE PARTS ARE TAM-
PERED WITH, AN ELECTRICAL SHOCK
MAY RESULT.

Do not expose periscope to bright light; pro-

longed exposure may cause damage to image
conversion tube.
NOTE
Special plate assemblies are provided for purg-
Figure 3-28 M42 Tank Periscope - Late Production ing and charging when the head assembly and
body assembly are separated. These plates are
also used for shipment and storage of the peri-
(a) Perform purging and charging procedure para scope.
2-5.b.
(1) Purging and Charging in the Installed Posi-
(b) Purge instrument at 5 psig for 5 minutes. tion (fig. 3-30).
(c) Charge instrument at 1 psig for 10 seconds.
(d) Leak test for minimum of 5 minutes.
(3) Modified Production (fig. 3-29). Refer to
para 3-10.h.(2) above for procedures.

Figure 3-30 M44A Series Tank Periscope

(a) Perform purging and charging procedure para

2-5.b.
(b) Purge instrument at 5 psig for 10 minutes.
Figure 3-29 M42 Tank Periscope - Modified (c) Charge instrument at 1 psig for 20 seconds.
Production (d) Leak test for minimum of 5 minutes.

3-13
TM 750-116

(2) Purging and Charging the Head Assem- (3) Purging and Charging the Body Assembly
bly (fig. 3-31). (fig. 3-32).
NOTE
NOTE
Mount plate 10549705 before proceeding with
Install plate 10542087 before performing purging purging and charging operations.
and charging procedures.

Figure 3-32 M44A Body Assembly

(a) Perform purging and charging procedure para

2-5.b.
Figure 3-31 M44A Head Assembly (b) Purge instrument at 5 psig for 10 minutes.
(C) Charge instrument at 1 psig for 20 seconds.
(d) Leak test for minimum of 5 minutes.
(a) Perform purging and charging procedure para
2-5.b.
j. Periscope, M44A2 Tank (figs. 3-30 through
(b) Purge instrument at 5 psig for 10 minutes. 3-32). Refer to para 3-10.i. for procedures.
(c) Charge instrument at 1 psig for 20 seconds.
k. Periscope, M44A3 Tank (figs. 3-30 through
(d) Leak test for minimum of 5 minutes. 3-32). Refer to para 3-10.i. for procedures.

3-14
 TM 750-116

l. Periscope, M44A4 Tank (figs. 3-30 through p. Periscope M48 Tank (fig. 3-34).
3-32). Refer to para 3-10.i. for procedures.

m. Periscope, M44A1E1 Tank (figs. 3-30 ENSURE THAT VEHICLE MASTER

through 3-32). Refer to para 3-10.i. for procedures. SWITCH IS IN OFF POSITION. THE
HIGH VOLTAGE AND LOW AMPERAGE
OF THE POWER PACK IS NOT DAN-
GEROUS; HOWEVER, IF THE HIGH
n. Periscope, M44A2E1 Tank (figs. 3-30
VOLTAGE PARTS ARE TAMPERED
through 3-32). Refer to para 3-10.i. for procedures.
WITH, AN ELECTRIC SHOCK CAN RE-
SULT.

o. Periscope, M47 Tank (fig. 3-33).

NOTE
Do not purge and charge the infrared body
The periscope body assembly must be separated assembly in bright light; prolonged exposure
from the head assembly or removed from stor- may cause damage to the image conversion
age for purging and charging procedures. Refer tube.
to appendix A for a listing of applicable publi- NOTE
cations.
The periscope body assembly must be separated
from the head assembly or removed from ve-
hicle storage for purging and charging proce-
dures. Refer to appendix A for a listing of
applicable publications.

Figure 3-33 M47 Tank Periscope Body Assembly

Figure 3-34 M48 Periscope Body Assembly

(1) Perform purging and charging procedure para
2-5.b. (1) Perform purging and charging procedure para
2-5.b.
(2) Purge instrument at 5 psig for 5 minutes.
(2) Purge instrument at 5 psig for 5 minutes.
(3) Charge instrument at 1 psig for 10 seconds. (3) Charge instrument at 1 psig for 10 seconds.
(4) Leak test for minimum of 5 minutes. (4) Leak test for minimum of 5 minutes,

3-15
TM 750-116

q. Periscope, M901 (fig 3-35). (l) Close nitrogen tank supply valve (CW) and re-
move hose assembly. Install dust cap on filler valve.
NOTE
Desiccant must be replaced every time unit is Ambient Air Temperature List
purged. Do not check pressure at any time oth- Air Temp. Pressurize to:
er than during the pressurizing cycle. Loss of Above +110°F (43°C) 4.0 psig
pressure resulting from such attempts will +85°F to +110°F (25°C to 43°C) 3.0 psig
shorten the time between maintenance actions. +55°F to +85°F (13°C to 29°C) 2.0 psig
Refer to appendix A for listing of applicable +30°F to +55°F (-1°C to 13°C) 1.0 psig
publications. +5°F to +30°F (-15°C to -l°C) 0.5 psig
Below +5°F (-15°C) 0 psig
(1) Upper Section.

Pressurizing in excess of 10 psig (68.95 kPa)

can cause damage to seals.
(a) Remove desiccator by unscrewing container part
(hex head) from tank periscope body.
(b) Hold container part upright and remove slotted
cap of desiccator by turning counterclockwise using screw-
driver and discard old desiccant.

To prevent damage to tank periscope, purge

charging lines by blowing pressurized nitro-
gen through lines. This will remove any con-
tamination in lines.
(c) Close pressure regulator valve (CCW). Open
nitrogen tank valve and observe nitrogen tank pressure
gauge, indicating tank is pressurized.
(d) Remove dust cap on filler valve. Install hose
assembly and loosen self-sealing screws in both upper and Figure 3-35 M901/M981 Tank Periscope
lower sections.
(e) Open pressure regulator valve (CW) to purge (2) Lower Section.
pressure of 4-5 psig (27.5 to 34.4 kPa) on low pressure
gage. Check that nitrogen is being discharged from self-
sealing screw holes.
(f) Alternately open and close self-sealing screw Pressurizing assemblies in excess of 10 psig
holes so one hole is open and another is closed every 15 (68.95 kPa) can cause damage to seals.
minutes. (a) Remove desiccant cap and old desiccant from
(g) Purge until humidity indicator is blue (approxi- desiccant container and install desiccant cap.
mately 30 minutes). (b) Close pressure regulator valve (CCW). Open
main valve on nitrogen tank and observe nitrogen tank pres-
(h) Close pressure regulator valve (CCW).
sure gage indicating tank is pressurized.
(i) Remove desiccator from tank periscope body. (c) Remove dust cap on filler valve and install valve
Remove slotted cap and install new desiccant. extension and hose.
(j) Lubricate preformed packing on desiccant cap (d) Remove l/4-inch upper and lower self-sealing
lightly with grease or silicone compound and install cap and screws.
desiccator. Torque cap to 20 to 30 in lb. (2 to 3 Nm).
(e) Open pressure regulator valve (CW) to purge
(k) Slowly open pressure regulator valve (CW) and pressure of 4-5 psig (27.5 to 34.4 kPa) on low pressure
pressurize upper section for 10 seconds to value given be- gage.. Check that nitrogen is being discharged from self-
low for ambient air temperatures. sealing screw holes.

3-16
 TM 750-116

(f) Alternately open and close self-sealing screw c. Quadrant, M15 (figs. 3-37 and 3-38).
holes so one hole is open and other is closed every 15 min-
utes. NOTE
(g) Purge until humidity indicator is blue. During For old configuration units, refer to figure 3-37.
purge, lubricate self-sealing screw preformed packing light- New configuration units are illustrated in figure
ly with silicone compound. 3-38.
(h) Close pressure regulator (CCW) and reinstall
two self-sealing screws.
(i) Remove desiccant cap and insert new desiccant
from sealed package immediately into desiccant container.
(j) Lubricate preformed packing on desiccant cap
lightly with grease or silicone compound and reinstall cap.
Torque cap to 20 to 30 lb in. (2 to 3 Nm).
(k) Slowly open regulator valve (CW) and charge
lower section for 10 seconds to value given in ambient air
temperature chart in para 3-10.q.
(l) Close nitrogen tank valve. Remove hose and
valve extension and install dust cap.

r. Periscope, M981 Tank (fig. 3-35). Refer to

para 3-10.q.. for procedures.

3-11. Quadrants.
a. Quadrant, M14 (fig. 3-36). Figure 3-37 M15 Quadrant - Old Configuration

(1) Perform purging procedure para 2-5.d.

(2) Purge instrument at 5 psig for 5 minutes.

Figure 3-36 M14 and M14A1 Quadrants

(1) Perform purging and charging procedure para

2-5.b.
(2) Purge instrument at 5 psig for 5 minutes.
(3) Charge instrument at 1 psig for 10 seconds.
(4) Leak test for minimum of 5 minutes.
Figure 3-38 M15 Quadrant - New Configuration

b. Quadrant, M14A1 (fig. 3-36). Refer to para

3-11.a. for procedures.

3-17
TM 750-116

d. Quadrant, M17, (fig. 3-39). 3-12. RANGEFINDERS.

a. Laser.
NOTE
(1) Optical Cavity (fig. 3-40).
While purging the quadrant, ensure the pressure NOTE
relief valve is working by checking for nitrogen See appendix C for Service Kit containing re-
gas escaping from the valve. placement parts for M1 and M1A1 Tanks.

Figure 3-39 M17 and M18 Quadrants

Figure 3-40 Laser Rangefinder Optical Cavity

(1) Perform purging and charging procedure para
2-5.a. (a) Remove cover and check lens for cracks and
breaks. If damage is evident, do not attempt purging and
(2) Purge instrument at 7 psig for 5 minutes. charging procedure.
(b) Perform purging procedure para 2-5.c.
(3) Turn pressure regulator off (CCW) and note when
(c) Remove inlet plug and preformed packing.
relief valve closes.
(d) Install valve extension on inlet port.
(4) If relief valve closes before reaching 1 psig, re- (e) Attach hose assembly to valve extension.
move hose assembly and depress valve core until all pres- (f) Loosen, but do not remove sealing screw.
sure has escaped.
(g) Purge instrument at 5 psig for 5 minutes.
(h) While purging, leak test lens area.
(5) Charge instrument at 1 psig for 60 seconds.
(i) Remove hose assembly and valve extension from
inlet port.
(6) Leak test for a minimum of 5 minutes.
(j) Reassemble by tightening sealing screw and in-
stalling cover.
(k) Install inlet port cap. Install inlet plug with pre-
e. Quadrant, M18 (fig. 3-39). Refer to para formed packing attached and outlet screw with preformed
3-11. d. for procedures. packing attached.

3-18
 TM 750-116

(2) Electronic Cavity (fig. 3-41). (1) Electronics Compartment.

NOTE
See appendix C for Service Kit containing re- (a) Perform purging procedure para 2-5.d.
placement parts for M1 and M1Al Tanks.
(b) Purge electronics compartment at 8 psig for 5
minutes.

(2) Receiver-Transmitter (R/T) Compartment.

Refer to para 4-12.b.(1) for procedures.

NOTE

Ensure nitrogen is escaping from the relief valve.

If not, repair as necessary.

(3) Optics Compartment. Refer to para

3-12.b.(1) for procedures.

(4) Laser Electronics Unit (fig. 3-43).

Figure 3-41 Laser Rangefinder Electronics Cavity

(a) Remove inlet screw with preformed packing
attached.
(b) Remove outlet screw with preformed packing
attached.
(c) Perform purging procedure para 2-5.d.
(d) Purge instrument at 5 psig for 5 minutes.

b. AN/VVG-2 Laser (fig. 3-42).

Figure 3-43 AN/VVG-2 Electronics Unit

(a) Perform purging procedure para 2-5.d.

Figure 3-42 AN/VVG-2 Receiver - Transmitter (b) Purge instrument at 8 psig for 5 minutes.

3-19
TM 750-116

c. M17A1, M17B1C, and M17C, (figs. 3-44 (2) End Housing Assemblies (figs. 3-45 and
through 3-46). 3-46).
NOTE
NOTE Blister and splatter shields must be removed for
end housing assembly purging and charging
Rangefinder end housings are purged and procedures.
charged on a yearly basis; however, they must
Some end housings have a relief valve instead
be visually inspected every 90 days.
of an outlet screw. When there is a relief valve,
disregard the procedure that removes the outlet
screw.
Purging pressure for end housings with relief
valves must be increased to 8 psig to open the
relief valve and keep it open during purging.
Charging pressure for housings with relief
valves is the 5 psig at which the relief valve
seats.

Figure 3-44 M17A1 Body Assembly

(1) Body Assembly (fig. 3-44)

Figure 3-45 M17A1 and M17C End Assembly
(a) Perform purging and charging procedure para (a) Remove inlet port cap and outlet screw with pre-
2-5.a. formed packing attached.
(b) Perform purging and charging procedure para
(b) Purge instrument at 8 psig for 30 minutes.
2-5.b.
(c) Ensure relief valve closes at 5 psig. (c) Purge instrument at 5 psig for 5 minutes.
(d) Charge instrument at 1 psig for 10 seconds.
(d) Leak test for a minimum of 5 minutes. (e) Leak test for minimum of 5 minutes.

3-20
 TM 750-116

NOTE NOTE
The end assembly for the M17BlC (fig. 3-46) The backup sight must be moved to gunner’s
is purged and charged in the same manner as position and the commander’s hatch cover
the M17A1 and M17C with the exception of opened and secured before purging and charg-
removing two outlet screws instead of one. ing. Refer to TM 9–2350-252-10-2.
Refer to para 3-12.c.(2) for procedures. (a) Perform purging and charging procedure para
2-5.b.
(b) Open valve stem (outlet screw) on outer head
assembly onlv three turns for purge procedure.
(c) Purge instrument at 5 psig for 5 minutes.
(d) Close valve stem (outlet screw) on outer head
assembly.
(e) Charge instrument at 5 psig.
(f) Leak test for minimum of 5 minutes.
(g) Close hatch and secure commander’s hatch cover.

(2) Integrated Sight Unit (figs. 3-48 and 3-49).

Figure 3-46 M17B1C End Assembly

3-13. SIGHTS.
a. BFV TOW/TOW2 SUBSYSTEM (M2, M3,
M2A1, M3A1, M2A2, AND M3A2 (figs. 3-47
through 3- 52).
(1) Backup Sight, PN 12316793, (fig. 3-47).

Figure 3-48 Integrated Sight Unit

ISU seals could rupture if pressure is too

high. Never let low pressure gage get higher
than 4 psig.
(a) Open and secure gunner’s hatch cover. (Refer to
TM 9-2350-252-l0-2 for M2, M3, M2A1, and M3A1 or
TM 9-2350-282-l0-2 for M2A2 and M3A2.)
(b) For M2, M3, M2A1, and M3A1 only, open sight
shield assembly per TM 9-2350-252-20–2-3.
(c) For M2A2 and M3A2 only, remove ballistic
Figure 3-47 Backup Sight, PN 12316793 sight shield assembly per TM 9-2350-284-20-2-3.

3-21
TM 750-116

(d) Perform purging and charging procedure para (k) For M2A1, M3A1, M2A2, and M3A2 only, re-
2-5.b. duce pressure from 4 psig to approximately 1.5 psig.
(e) Remove outlet port screw and discard. (l) For M2, M3, M2A1, and M3A1 only, close sight
(f) Purge instrument at 4 psig for 10 minutes or until shield assembly per TM 9-2350-252-20-2-3.
all visible traces of moisture are gone. (m) For M2A2 and M3A2 only, install ballistic sight
(g) Apply thin coat of lubricant (item 3, appx B) to shield assembly per TM 9-2350-284-20-2-3.
o-ring of replacement outlet port screw and install. (n) Close and secure gunner’s hatch cover per TM
(h) Torque outlet port screw to 24-28 in-lb (28-32 9-2350-252-10-2 (for M2, M3, M2A1, and M3A1 only) or
cm kg). TM 9-2350-284-10-2 (for M2A2 and M3A2 only).
(i) Charge instrument at 4 psig for 10 minutes. (3) Commander’s Relay Assembly (figs. 3-50
and 3-51).
(j) Leak test instrument for minimum of 10 minutes.
If leak is detected, repair per table 3-1.
Table 3-1 Leak Test, Integrated Sight Unit

Part leak de- Manual re- Manual re-

tected from ferred for M2, ferred for
M3, M2A1, and M2A2 and
M3A1 vehicles M3A2 vehicles
lamp window TM9-2350-252- TM9-2350-284-
collar assembly 20-2-3 20-2-3
lampholder as- TM9-2350-252- ——
sembly cover 20-2-3
valve assembly TM9-2350-252- TM9-2350-284-
20-2-3 20-2-3
all other parts of TM9-1425-474- TM9-1425-453-
ISU 34-1 (M2/M3) 34-1
TM9-1425-453-
34-1 (M2A1/
M3A1) Figure 3-50 Commander’s Relay Assembly

LAMP WINDOW COLLAR ASSEMBLY

Commander’s Relay Assembly seals could

rupture if pressure is too high. Never let low
pressure gage get higher than 4 psig.
(a) Open and secure gunner’s hatch cover per TM
9-2350-252-10-2 (for M2, M3, M2A1, and M3A1 only) or
TM 9-2350-284-10-2 (for M2A2 and M3A2 only).
NOTE
Shim(s) may or may not be present between
night sight cover support and turret.
LAMPHOLDER COVER (M2, M3, ONLY) (b) For M2A2 and M3A2 only, remove two screws,
washers, shim(s), and night sight cover actuator handle/sup-
Figure 3-49 Lamp Assembly port.

3-22
 TM 750-116

Table 3-2 Leak Test, Commander’s Relay

Assembly
Part leak Manual re- Manual re-
detected from ferred for M2, ferred for
M3, M2A1, and M2A2 and
M3A1 vehicles M3A2 vehicles
valve assembly TM9-2350-252- TM9-2350-284-
20-2-3 20-2-3
commander’s TM9-1425-474- TM9-1425-453-
eyepiece assem- 34-1 (M2/M3) 34-1
bly TM9-1425-453-
34-1 (M2A1/
M3A1)
all other parts of DMWR DMWR
commander’s 9-1240-394 9-1240-399-1
relay asembly (M2, M3)
Figure 3-51 Night Sight Cover Actuator DMWR
Handle/Support 9-1240-399-1
(M2A1, M3A1)
(c) Perform purging and charging procedure para
2-5.b. (j) For M2A2 and M3A2 only, apply primer item 4,
appx B) and sealing compound (item 5, appx B) to threads
(d) Remove outlet port screw and discard. of two screws. Position shim(s), night sight cover actuator
(e) Purge instrument at 4 psig for 3-5 minutes or handle/support and install two washers and screws.
until all visible traces of moisture are gone. (k) Close and secure gunner’s hatch cover per
(f) Apply thin coat of lubricant (item 3, appx B) to TM 9-2350-252-10-2 (for M2, M3, M2A1, and M3A1
o-rings of replacement outlet port screw and install. only) or TM 9-2350-282-10-2 (for M2A2 and M3A2
only).
(g) Torque outlet port screw to 10-12 in-lb (12-14 b. 8635466 Infinity Sight (fig. 3-52).
cm kg).
NOTE
(h) Charge instrument at 4 psig for 10 minutes.
Infinity sights 8635466 are identified as early
(i) Leak test instrument for minimum of l0 minutes. and late production models. The procedures for
If leak is detected, repair per table 3-2. purging and charging apply to later production
models only.

Figure 3-52 8635466 Infinity Sight

3-23
TM 750-116

(1) Perform purging and charging procedure para

2-5.b.

(2) Purge instrument at 5 psig for 5 minutes.

(3) Charge instrument at 1 psig for 10 seconds.

(4) Leak test for a minimum of 5 minutes.

c. M44C Infinity Sight (fig. 3-53).

NOTE

M44C sights are equipped with two types of

inlet ports. Some sights require the use of an
adapter. If this is the case, use purging proce-
dure para 3-5.e.)

Figure 3-54 M61 Computing Sight

(1) Perform purging procedure para 2.5.b

(2) Purge instrument at 5 psig for 5 minutes.
(3) Charge instrument at 5 psig for 5 minutes.
(4) Leak test for a minimum of 10 minutes.
e. Commander’s Extension, PN 12285300 (fig.
3-55).

Figure 3-53 M44C Infinity Sight

Figure 3-55 Commander’s Extension PN 12285300

(1) Remove outlet plug, spring, and plunger.
(1) Perform purging and charging procedure para
(2) Perform purging procedure para 2-5.c 2-5.a.
(2) Purge instrument at 8 psig for 5 minutes.
(3) Purge instrument at 5 psig for 5 minutes.
(3) Ensure relief valve closes at 5 psig.
(4) Leak test for a minimum of 5 minutes.

3-24
 TM 750-116

f. Control Unit, Image (fig. 3-56). g. Gunner’s Auxiliary Sight, PN 12278900 (fig.
3-57).

Figure 3-57 Gunner’s Auxiliary Sight PN 12278900

(1) Perform purging and charging procedure para
Figure 3-56 Image Control Unit 2-5.a.
(2) Purge instrument at 8 psig for 10 minutes.
(1) Loosen, but do not remove setscrews in the con- (3) Ensure relief valve closes at 5 psig.
trast knob, reticle knob, sensitivity knob, symbols knob, (4) Leak test for a minimum of 5 minutes.
unit test pattern knob, and two boresight knobs from the h. Gunner’s Primary Sight, PN 12282140,
front panel. PN 12549761-2, PN 12549761-3, and
(2) Remove all knobs from the unit. PN 9377279-2 (fig. 3-58).
(3) Perform purging and charging procedure para
2-5.a.
(4) Purge instrument at 10 psig for 3 minutes.
(5) Ensure relief valve closes at 5 psig.
(6) Leak test all sealed joints, screws, control shafts,
purging valve, and relief valve for minimum of 15 minutes.
(7) Install knobs on front panel.

Figure 3-58 Gunner’s Primary Sight PN 12282140,

PN 12549761-2, PN 12549761-3, PN 9377279-2
(1) Perform purging and charging procedure para
2-5.a.
(2) Purge instrument at 6 psig for 5 minutes.
(3) Ensure relief valve closes at 5 psig.
(4) Leak test for minimum of 5 minutes.

3-25
TM 750-116

i. Tank Thermal Sight, (3) Head Assembly (fig. 3-61). Refer to para
(1) Commander’s Display (fig. 3-59) 3-13.i.(1) for procedures.

Figure 3–59 Commander’s Display

(a) Perform purging and charging procedure para Figure 3-61 Head Assembly
2-5.a.
(b) Purge instrument at 8 psig for 5 minutes. (4) Power Converter (fig. 3-62). Refer to para
(c) Ensure relief valve closes at 5 psig. 3-13.i.(1) for procedures.
(d) Leak test for minimum of 5 minutes.
(2) Gunner’s Display (fig. 3-60). Refer to para
3-13.i.(1) for procedures.

Figure 3-60 Gunner’s Display Figure 3-62 Power Converter

3-26
 TM 750-116

j. Weapon Sight, PN 12279200 (fig. 3-63). (3) Purge instrument at 5 psig for 10 minutes.

(4) Charge instrument at 1 psig for 40 seconds.

(5) Leak test for minimum of 5 minutes.

b. Articulated Telescope, M105F (fig. 3-64).

Refer to para 3-14.a. for procedures.

c. Articulated Telescope, M127 (fig. 3-65).

(1) Eyepiece Assembly.

Figure 3-63 Weapon Sight, PN 12279200

(1) Perform purging and charging procedure para

2-5.a.
(2) Purge instrument at 7 psig for 5 minutes.
(3) Ensure relief valve closes at 5 psig.
(4) Leak test for minimum of 5 minutes.
3-14. Telescopes, Articulated.
a. Articulated Telescope, M105D (fig. 3-64).
NOTE
The telescope must be removed from the in-
stalled position for purging and charging proce-
dures. Refer to appendix A for a listing of
applicable publications.

Figure 3-65 M127 Articulated Telescope

(a) Perform purging and charging procedure para

2-5.a.

(b) Purge instrument at 8 psig for 10 minutes.

(c) Ensure relief valves close at 5 psig.

Figure 3-64 M105D Series Telescope (d) Leak test for minimum of 5 minutes.
(2) Objective Assembly. Refer to para 3-14.c.(1)
(1) Remove inlet port cap and outlet plug with gasket for procedures.
attached.
(2) Perform purging and charging procedure para d. Articulated Telescope, M127A1 (fig. 3-61).
2-5.b. Refer to para 3-14.a. for procedures.

3-27
TM 750-116

3-15. Telescopes, Elbow. e. Elbow Telescope, M138 (fig. 3-68).

a. Elbow Telescope, M114 (fig. 3-66).

Figure 3-66 M114 Elbow Telescope

(1) Perform purging and charging procedure para

2-5.b. Figure 3-68 M138 Elbow Telescope

(2) Purge instrument at 5 psig for 5 minutes.

(1) Perform purging and charging procedure para
(3) Charge instrument at 1 psig for 10 seconds.
2-5.a.
(4) Leak test for minimum of 5 minutes.
(2) Purge instrument at 8 psig for 5 minutes.
b. Elbow Telescope, M114A1 (fig. 3-66). Refer
to para 3-15.a. for procedures. (3) Ensure relief valve closes at 5 psig.
c. Elbow Telescope, M16 and M116 Series (fig. (4) Leak test for minimum of 5 minutes.
3-69). Refer to para 3-15.f. for procedures.
f. Elbow Telescope, M139 (fig. 3-69).
d. Elbow Telescope, M118 Series (fig. 3-67).
NOTE
The telescope must be removed from the in-
stalled position for purging and charging proce-
dures. Refer to appendix A for a listing of
applicable end item manuals.

Figure 3-67 M118A2/M118A3 Elbow Telescope

Figure 3-69 M139 Elbow Telescope
(1) Perform purging and charging procedure para
2-5.b.
(1) Perform purging procedure para 2-5.d.
(2) Purge instrument at 5 psig for 15 minutes.
(3) Charge instrument at 1 psig for 1 minute. (2) Purge instrument at 5 psig for 5 minutes.
(4) Leak test for minimum of 5 minutes.

3-28
 TM 750-116

3-16. Telescopes, Panoramic.

a. Panoramic Telescope, M12A7Q (fig. 3-70).

Figure 3-70 M12A7Q Panoramic Telescope Figure 3-71 M113 and M113A1 Panoramic
Telescope
(1) Perform purging procedure 2-5.d.
(2) Purge instrument at 5 psig for 5 minutes.
(2) Optical Assembly (fig. 3-71).
b. Panoramic Telescope, M12A7S (fig. 3-70). (a) Remove optical inlet port cap and optical outlet
Refer to para 3-16.a. for procedures. screw.

(b) Perform purging and charging procedure para

c. Panoramic Telescope, M113 and M113A1 2-5.b.
(fig. 3-71).
(1) Counter Box Assembly. (c) Purge instrument at 5 psig for 5 minutes.
(a) Remove counter box inlet port cap and outlet (d) Charge instrument at 3 psig for 10 seconds.
port cap.
(b) Perform purging procedure para 2-5.c. (e) Leak test for minimum of 5 minutes.

(c) Purge instrument at 5 psig for 5 minutes.

3-29
TM 750-116

d. Panoramic Telescope, M115 (fig. 3-72). e. Panoramic Telescope, M117/M117A1 (fig.

(1) Counter Box Assembly. 3-73).

(a) Remove counter box inlet port cap and outlet (1) Counter Box.
port cap. (a) Remove counter box inlet port cap and outlet
port cap.
(b) Perform purging procedure para 2-5.c.
(b) Perform purging procedure para 2-5.c.
(c) Purge instrument at 5 psig for 5 minutes.
(c) Purge instrument at 5 psig for 5 minutes.

Figure 3-72 M115 Panoramic Telescope Figure 3-73 M117/M117A2 Panoramic Telescope
(2) Optical Assembly. (2) Optical System.
(a) Remove optical system inlet port cap and outlet (a) Remove optical system inlet port cap and outlet
screw. screw.
(b) Perform purging and charging procedure para (b) Perform purging and charging procedure para
2-5.b. 2-5.b.
(c) Purge instrument at 5 psig for 5 minutes. (c) Purge instrument at 5 psig for 5 minutes.
(d) Charge instrument at 1 psig for 10 seconds. (d) Charge instrument at 1 psig for 10 seconds.
(e) Leak test for minimum of 5 minutes. (e) Leak test for minimum of 5 minutes.

3-30
 TM 750-116

f. Panoramic Telescope M137 (fig. 3-74). (c) Purge instrument at 7 psig for 5 minutes.
g. Panoramic Telescope, M137A1 (fig. 3-75).

HANDLE WITH CARE. IN THE EVENT

THE RADIOLUMINOUS SOURCE IS
HANDLE WITH CARE. IN THE EVENT
BROKEN, CRACKED, OR SUDDENLY
THE RADIOLUMINOUS SOURCE IS
LOSES ILLUMINATION, DO NOT AT-
BROKEN, CRACKED, OR SUDDENLY
TEMPT TO REPAIR. IMMEDIATELY
LOSES ILLUMINATION, DO NOT AT-
DOUBLE WRAP INSTRUMENT IN PLAS-
TEMPT TO REPAIR. IMMEDIATELY
TIC AND NOTIFY THE LOCAL RADI-
DOUBLE WRAP INSTRUMENT IN PLAS-
ATION PROTECTION OFFICER (RPO).
TIC AND NOTIFY THE LOCAL RADI-
(1) Counter Box. ATION PROTECTION OFFICER (RPO).
(a) Remove counter box inlet port cap. (1) Counter Box.
(b) Perform purging and charging procedure para (a) Perform purging and charging procedure para
2-5.a. 2-5.a.
(c) Purge instrument at 7 psig for 5 minutes. (b) Relief valve should open between 3-10 psig.
(d) Ensure relief valve closes at 5 psig. (c) Purge instrument at 7 psig for 5 minutes.
(e) Leak test for minimum of 5 minutes. (d) Ensure relief valve closes between 1-5 psig.
(e) Leak test for minimum of 5 minutes.

Figure 3-74 M137 Panoramic Telescope

(2) Optical Assembly.
(a) Remove optical inlet port cap.
(b) Perform purging procedure para 2-5.a Figure 3-75 M137A1 Panoramic Telescope

3-31
TM 750-116

(2) Optical System.

(a) Perform purging and charging procedure para
2-5.a.
(b) Relief valve should open between 3-10 psig. Contamination can damage the telescope.
Blow pressurized nitrogen through the
(c) Purge instrument at 7 psig for 5 minutes. charging lines to remove contamination.
(d) Ensure relief valve closes between 1-5 psig.
(5) Open tank supply valve and observe high pressure
(e) Leak test for minimum of 5 minutes. gauge indicating that tank is pressurized.
(6) Remove lockwire and cap from valve stem.
h. Panoramic Telescope, M901A1 (fig. 3–76).
NOTE
Purge panoramic telescope when the internal
optical surfaces are fogged over. Replace the
desiccant and two preformed packings every The sealscrew is a captive screw and must
time the unit is purged. Do not attempt to check not be removed. Removal of the screw dam-
the pressure in the panoramic telescope at any ages equipment.
other time than during the pressurization cycle. (7) Install hose assembly on valve stem and loosen
Loss of pressure resulting from such attempts setscrew.
will shorten the time between maintenance
actions. (8) Adjust pressure regulator to 4-5 psig (28 to 34
(1) Remove desiccator by unscrewing container part kPa) as indicated on low pressure gauge.
(hex head) from telescope body. (9) Verify nitrogen is being vented from sealscrew
(2) Hold container part upright and remove slotted cap hole and observe humidity indicator.
of desiccator.
(10) Purge telescope until all sections of indicator are
(3) Discard old desiccant. Discard two preformed blue. During purge, lubricate preformed packings lightly
packings from desiccator. Install desiccator. with silicone compound.
(11) Close pressure regultor valve and tighten set-
screw.
(12) Remove dessicator from telescope body and refill
desiccator to level slightly below threads.

(13) Lightly lubricate preformed packing on top part

of desiccator with grease or silicone compound.
(14) Install top part of desiccator to bottom.
(15) Lightly lubricate preformed packing with grease
or silicone compound.
(16) Install desiccator on telescope body and tighten
to 20 to 30 in lb. (2.25 to 3.39 Nm).
(17) Slowly open pressure regulator valve and charge
instrument to 2.0 + or - .0.5 psig (14 + or - 3 kPa). Tighten
setscrew when pressure regulator gauge stabilizes.
(18) If overpressurization occurs, slowly open set-
screw, adjust pressure regulator to 2.0 + or - 0.5 psig; then
tighten setscrew when pressure regulator gauge stabilizes.
(19) Close pressure regulator gauge. Remove hose
Figure 3-76 Panoramic Telescope, M901A1 assembly and replace cap on nut of valve and install lock-
wire.
(4) Close nitrogen tank valve and pressure regulator (20) Close tank supply valve and verify on high pres-
valve. sure gage.

3-32
 TM 750-116

i. Panoramic Telescope, M981 FISTV (fig. b. M134 Straight Telescope (fig. 3-78).
3-76). Refer to 3-16.h. for procedures. NOTE
The telescope must be removed from the ve-
3-17. Telescopes, Straight. hicle or the vehicle storage area before begin-
ning purging procedures. Refer to appendix A
a. M90A2 Straight Telescope (fig. 3-77).
for a listing of applicable publications.

HANDLE WITH CARE. IN THE EVENT

THE RADIOLUMINOUS SOURCE IS Figure 3-78 M134 Straight Telescope
BROKEN, CRACKED, OR SUDDENLY
LOSES ILLUMINATION, DO NOT AT-
TEMPT TO REPAIR. IMMEDIATELY (1) Perform purging procedure para 2-5.d.
DOUBLE WRAP INSTRUMENT IN PLAS- (2) Purge instrument at 5 psig for 5 minutes.
TIC AND NOTIFY THE LOCAL RADI-
ATION PROTECTION OFFICER (RPO). 3-18. T e s t Set, Receiver/Transmitter (fig.
3-79).

Figure 3-77 M90A2 Straight Telescope

(1) Perform purging and charging procedure para

2-5.a. Figure 3-79 Receiver/Transmitter Test Set
(2) Relief valve should open between 3-10 psig.
a. Perform purging and charging procedure para 2-5.b.
(3) Purge instrument for 5 minutes. b. Purge instrument at 10 psig for 15 minutes.
(4) Relief valve should close between 1-5 psig. c. Charge instrument at 1 psig for 10 minutes.
(5) Leak test for a minimum of 5 minutes. d. Leak test for minimum of 5 minutes.

3-33
 TM 750-116

3-19. Trainer, M55 Laser (figs. 3–80 and (1) Perform purging procedure para 2-5.d.
3-81). (2) Purge instrument at 5 psig for 2 minutes.
a. Barrel Assembly (fig. 3-80).
3–20. Unit, Reticle Projector (fig. 3-82).

Figure 3-80 M55 Barrel Assembly

(1) If necessary, remove the barrel extension by turn-
ing it counterclockwise.
(2) Remove the lens guard and loosen the outlet
screw.
(3) Perform purging and charging procedure para
2-5.b.
(4) Purge instrument at 5 psig for 2 minutes.
(5) Charge instrument at 1 psig for 1 minute. Figure 3-82 Reticle Projector Unit
(6) Leak test for minimum of 5 minutes.
(7) Tighten outlet screw and install lens guard. a. Perform purging procedure para 2-5.c.
b. Purge instrument at 8 psig for 5 minutes.
b. Deflector Optical Assembly (fig. 3-81).

Figure 3-81 M55 Deflector Optical Assembly

3-34
 TM 750-116

APPENDIX A
REFERENCES

A-1. SCOPE.
This appendix lists all forms, field manuals, technical manuals, and miscellaneous publications referenced in this manual.

A-2. FORMS.
Recommended Changes to Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..DA Form 2028
Recommended Changes to Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. DA Form 2028-2
Quality Deficiency Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..SF 368

A-3. FIELD MANUALS.

First Aid for Soldiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..FM 21-11

A-4. TECHNICAL MANUALS.

General Maintenance Procedures for Fire Control Materiel ....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..TM 9-254
Procedures for Destruction of Aviation General Support Equipment to Prevent Enemy Use . . . . . . . . . . . .. TM 750-244-1-4
Procedures for Destruction of Equipment to Prevent Enemy Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..TM 750-244-3

The following publications should be referred to for removal and installation instructions.

FIRE CONTROL END ITEM

INSTRUMENT TM REFERENCE APPLICATION TM REFERENCE

Aiming Circle, M2A2 9-1290-262-24
Backup Sight BFVS M2/M3 9-2350-252-10-2
Collimator, M1Al 9-1240-324-34&P
Commander’s Relay Assy. BFVS 9-2350-252-l0-2
M2/M3/M2A1/M3A1 9-2350-252-20-3
9-1425-474-34-l(M2/M3)
9-1425-453–34-l
(M2A1/M3Al)
Commander’s Relay Assy. BFVS M2A2/M3A2 9-2350-284-10-2
9-2350-284-20-2-3
9-1425-453-34-1
Integrated Sight Unit BFVS 9-2350-252-10-2
M2/M3/M2Al/M3Al 9-2350-252-20-2-3
9-1425-474-34-l(M2/M3)
9-1425-453-34-1
(M2A1/M3Al)
Integrated Sight Unit BFVS M2A2/M3A2 9-2350-284-10-2
9-2350-284-20-2-3
9-1425453–34-1
Mount, M137 9-1240-400-34 M11OA2 9-2350-304-20-2
Mount, M145/M145Al 9-1240-401-34&P M109A2/A3/A4/A5 9-2350-311-20-2

A-1
TM 750-116

A-4. TECHNICAL MANUALS – continued

FIRE CONTROL END ITEM

Mount, M149/M149A1 9-1240-312-34 M551/M551Al 9-2350-230-20-2

Muzzle Boresight 9-4933-259-14&P
M26A1/M27Al
Periscope, M30C M48A5 9-2350-258-20-2
Periscope, M32E1 9-1240-313-34 M48A5 9-2350-258-20-2
Periscope, M32CE1/M35El 9-1240-313-34 M60/M60A1 9-2350-222-2 Series
Periscope, M36 Series 9-1240-314-34 CEV M728 9-2350-222-20-2 Series
M60/M60A1 9-2350-257-20-2 Series
Periscope, M42 9-1240-401-34 M109A2/A3/A4/A5 9-2350-31l-20-2
Periscope, M47 9-6650-221-35 M551/M551Al 9-2350-230-20-l
Periscope, M48 9-6650-222-35 M551/M551A1 9-2350-230-20-l
Periscope, M65, 9-1240-368-34
Battery Commander’s
Quadrant, M15 9-1290-322-34&P M109A2/A3/A4/A5 9-2350-311-20-2
Telescope, M105D 9-1240-262-34 M60A1 9-2350-215-20-2 Series
M60A3 9-2350-252-20-2
M60A1 Rise/ 9-2350-257-20-2 Series
M60A2Rise Passive
M48A5 Tank 9-2350-258-20-2
M60 Tank 9-2350-260-20-2 Series
Telescope, M105F 9-1240-262-34 CEV M728 9-2350-222-20-2 Series
Telescope, Panoramic, M115 9-1240-400-34 M11OA2 9-2350-304-20-2
Telescope, Panoramic, 9-1240-401-34&P M109A2/A3/A4/A5 9-2350-311-10
Ml17/Ml17A2 M109A6 9-2350-314-10
Telescope, 9-1240-401-34&P M109A2/A3/A4/A5 9-2350-311-10
Ml18A2/Ml18A3
Telescope, M134 9-1240-318-35 Vulcan SP, M163A1 9-2350-300-10
Vulcan, Towed M167A1 9-2350-286-10
Towed Pivads M167A2 9-1005-318-10

A-5. SUPPLY CATALOGS.

Purging Kit, Fire Control: Organizational, Direct and General Support Maintenance
and Hand Receipt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. SC 4931-95-J54

A-6. MISCELLANEOUS PUBLICATIONS.

The Army Maintenance Management System (TAMMS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. DA PAM 738-750

A-2
 TM 750-116

APPENDIX B
EXPENDABLE SUPPLIES AND MATERIALS LIST

Section I. INTRODUCTION
B-1. SCOPE.

This appendix lists expendable supplies and materials you will need to purge and charge fire control instruments. These items
are authorized to you by CTA 50-970, Expendable Items (Except Medical, Class V, Repair Parts, and Heraldic Items).
B-2. EXPLANATION OF COLUMNS.

a. Column (1) - Item number. This number is assigned to the entry in the listing and is referenced in the narrative in-
structions to identify the material (e.g., “Use sealing compound, item ......, appendix B“).

b. Column (2) - National Stock Number. This is the National stock number assigned to the item; use it to request or
requisition the item.

c. Column (3) - Description. Indicates the Federal item name and, if required, a description to identify the item. The last
line for each item indicates the Contactor and Government Entity Code (CAGEC) in parentheses followed by the part number.

d. Column (4) - Unit of Measure (U/M). Indicates the measure used in performing the actual maintenance function.
This measure is expressed by a two-character alphabetical abbreviation (e.g., ea, in, pr). If the unit of measure differs from
the unit of issue, requisition the lowest unit of issue that will satisfy your requirements.

Section II. EXPENDABLE SUPPLIES AND MATERIALS LIST

(2) (3) (4)

NATIONAL STOCK DESCRIPTION U/M
NUMBER
1 8105-00-150-6256 Bag, plastic, general purpose, 44 x 32 inches BX

2 6830-00–782-2641 Nitrogen, technical, oil–free, Gas form, CF

(81348), Type 1, BB-N-411, Grade B,
Class 1
3 1240-01-189-4372 Lubricant (18876), MIS-23546
I QT

8030-00-900-2373 Sealing Compound, Primer (05972), MIL- OZ

S-22473, Grade N, Form R; MIL-R-46082,
Grade F MIL-S-46162, Grade N;
764-55
8030-01-166-0575 Sealing Compound (05972), 567-47

6 8030-00-275-8114 Sealing Compound, adhesive, noncuring,

polysulfide base, type 1, (80064), 1941316

I 7 8520-00-228-0598 Soap, toilet, liquid, l–gallon container:

(81348) P-S-624
GL

B-1 (B-2 blank)

 TM 750-116

APPENDIX C

ADDITIONAL SUPPLIES

C-1. COMMON TOOLS AND EQUIPMENT. For authorized common tools and equipment, required to per-
form the operations described in this manual refer to the Modified Table of Organization and Equipment (MTOE) applicable
to your unit.

C-2. OUTLET PORT SCREWS AND PLUGS. Table C-1 lists replacement self-sealing screws and plugs for
outlet ports. Select replacement hardware by determining the thread size and depth of the port requiring hardware.

Table C-1. Self-Sealing Outlet Screws and Plugs

Part No. National Stock No. Thread Length (inches)

AN505-4R5 5305-00-639-7518 4-4OUNC, Screw, Machine 5/16
FFS92 5305-00-011-0499 10-24UNC, Screw, Machine 3/8
MS3212-1 5305-00-738-0624 40-UNC-2A, Screw, Machine 1/4
MS3212-21 5305-00-433-3707 8-32UNC, Screw, Machine 1/4
MS3212-31 5305-00-855-2989 10-32UNF, Screw, Machine 3/8
MS3212-39 5305-00-085-4056 24UNC, Screw, Machine 3/8
MS5103-33 5305-00-724-3439 8-36UNF, Setscrew 1/8
MS I 6996-40 5305-00-068-8202 10-24UNF, Screw, Cap, Socket Head 1
MS35266-61 5305-00-543-2753 10-32UNF, Screw, Machine 3/8
MS35375-239 5305-00-939-9219 8-32UNC, Screw, Machine 1/8
MS49005-2 4730-00-01 8–9566 1/8 NPT, Plug, Pipe 1/4
MS51957-13 5305-00-054-5647 4-4OUNC, Screw, Machine 1/4
MS51957-59 5305-00-050-9225 10-24UNC, Screw, Machine 1/4
MS51958-24 5305-0>964-0310 6-4OUNC, Screw, Machine 1/8
0228372 5305-00-003-7126 8-32UNC, Screw, Machine 1/2 I
100697 5305-00-010-0697 6-32UNC, Screw, Machine 1/4
10541671 5305-00-997-4604 4-4OUNC, Screw, Shoulder 3/1 6
105551 57–1 5305-00-085-3706 4-4OUNC, Screw, Machine 3/1 6
105551 57–2 5305-00-606-8179 4-40UNC, Screw, Machine 1/4
10555157-4 5305-00-955-2941 6-32UNC, Screw, Machine 3/16
10555157-6 5305-00-41 9–3378 6-32UNC, Screw, Machine 5/16
10555157-7 5305-00-740-8890 6-32UNC, Screw, Machine 3/8
105551 57–8 5305-01-057-9300 8-32UNC, Screw, Machine 1/4
105551 57–11 5305-00-1 82–7302 10-32UNF, Screw, Machine 1/4
105551 57–14 5305-00-524-0709 10-24UNC, Screw, Machine 1/4
11737540-2 5305-00-245-5157 10-32UNC, Screw, Self-locking 3/8
11737718 5305-00-111 –5540 8-32UNC, Screw, Machine 3/4

C - 1
 TM 750-116

Table C-1. Self-Sealing Outlet Screws and Plugs (continued)

8574881 5305-00-684-4401 3/8-32UNF, Plug, Machine Thread 1/6

8624877 5305-00-857-5190 8-32UNC, Screw, Machine 1/4
8626469 5305-00-959-6865 4-4OUNC, Screw, Self-locking 5/32
8643632 5305-00-930-1808 8-32UNC, Screw, Machine 1/4

C-3. INLET PORT SCREWS. Table C-2 lists replacement screws for purging inlet ports. Select replacement
hardware by determining the thread size and depth of the port requiring hardware.

Table C-2. Self-Sealing Screws, Inlet

Part Number National Stock Number Thread Length (inches)

MS3212-21 5305-00-433-3707 8-32UNC, Screw, Machine 1/4
MS3212-31 5305-00-855-2989 10-32UNC, Screw, Machine 3/8
MS16996-40 5305-00-068-8202 10-24UNC, Screw Cap, Socket Head 1
8624877 5305-00-857-5190 8-32UNC, Screw, Machine 1/4
11737540-1 5305-00-262-0077 6-32UNC, Screw, Self–locking 3/16
11737540-2 5305-00-245-5157 10-32UNF, Screw, Self-locking 3/8

C-4. PNEUMATIC VALVES. Table C-3 lists replacement pneumatic valves for inlet and outlet ports. Select re-
placement hardware by determining the thread size and depth of the port requiring hardware.

Table C-3. Pneumatic Valves Assemblies/Components

Part Number National Stock Number Description

MS51607-1 1240-00-114-1096 Valve Stem
MS51377-2 2640-00-060-3543 Valve Core
MS20813-1 2644-00-222-4525 Cap
SM-C-805978-1 4820-00-427-5047 Schroeder
SM-C-805845 5885-01-063-1403 Schroeder
10556186 4820-01-053-0223 Relief, 5 psig
8200055 2640-00-507-9260 Cap
10516567 1240-00-464-4792 Strap
11737597 5310-00-096-9728 Nut, plain hexagon

C-2
 TM 750-116

C-5. PARTS KITS. Table C-4 lists the parts kits to be used for specific applications.
Table C-4. Parts Kits

Part Number National Stock Number Application

5705155* 1240–01–114-3070 Laser Rangefinder for
M1/M1A1 Tank

*For M1 Tank, this kit is part of Service Kit, Laser; Part No. 5705438, NSN 2540-01-255-3347.
For M1A1 Tank, this kit is part of Service Kit, Laser; Part No. 5705137, NSN 3640-01-117-7942.

C-3 (C-4 blank)

 TM 750-116

INDEX
SUBJECT PAGE
A
Additional Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
Aiming Circle, M2A2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Applicable Publications, List of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
B
Binocular, M19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Bleed Down of Purging and Charging Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
C
Collimator, M1A1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Common Tools and Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
Computer, M21, Electronic, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Corrosion Prevention and Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
D
Destruction of Army Materials to Prevent Enemy Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Device, Alinement
M139/M140 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Devices, Boresight
M26/M27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
M26A1/M27Al Muzzle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
E
Equipment Characteristics, Capabilities, and Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Expendable Supplies and Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
F
Field Manuals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..A-1
Forms, Records, and Reports, Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..1-1
Forms, References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..A-l
I
Inlet Port Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..C-2
M
Maintenance Forms. Records and Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..1-1
Mounts, Telescope
M137 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...3-6
M145/M145Al . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...3-6
M149/M149El . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...3-6
M187 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-7
O
Outlet Port Screws and Plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-l
P
Parts Kits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..C-3
Periscope, M65 Battery Commander’s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-7
Periscopes, Tank
M28C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-8
M30C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-8
M32E1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-9

Index 1
 TM 750-116

INDEX – Continued
SUBJECT PAGE
Periscopes, Tank - continued
M32CE1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
M35E1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
M36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
M36E1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
M42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
M44A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
M44A2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
M44A3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
M44A4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
M44A1E1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
M44A2E1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
M47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
M48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
M901 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
M981 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
Pnuematic Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2
Publications, Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2
Purging and Charging Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Q
Quadrants
M14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
M14A1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
M15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
M17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
M18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
R
Rangefinders
Laser . . . . . . . . . . . . 3-18
AN/VVG-2 Laser . . 3-19
M17A1, M17B1C, M17C 3-20
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
Reporting Equipment Improvement Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
S
Safety, Care, and Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Screws
Inlet Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2
Outlet Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
Setup of Purging and Charging Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Sights
BFV Tow/Tow2 Subsystem.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21
Backup Sight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21
Integrated Sight Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21
Commander’s Relay Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-22
8635466 Infinity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23
M44C Infinity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
M61 Computing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
Commander’s Extension, PN 12285300 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
Control Unit, Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-25
Gunner’s Auxiliary Sight PN 12278900 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-25

Index 2
 TM 750-116

INDEX - Continued
SUBJECT PAGE
Sights - continued
Gunner’s Primary Sight PN 12282140, PN 1254976 1-2, PN 12549761-3, PN 9377279-2 . . . . . . . 3-25
Tank Thermal Sight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-26
Weapon Sight PN 12279200 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-27
Supply Catalogs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-2
T
Technical Manuals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-l
Telescopes, Articulated
M105D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27
M105F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27
M127 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-27
M127A1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...3-27
Telescopes, Elbow
M114 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-28
M114A1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-28
M16 and M116 Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-28
M118 Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-28
M138 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-28
M139 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-28
Telescopes, Panoramic
M12A7Q . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...3-29
M12A7S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-29
M113 and M113A1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-29
Ml15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-29
M117/M117A1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-30
M137 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-31
M137A1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-31
M901A1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-32
M981 FISTV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-33
Telescopes, Straight
M90A2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...3-33
M134 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...3-33
Test Set, Receiver/Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-33
Time Cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..2-3
Trainer, M55 Laser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-34
U
Unit, Reticle Projector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..3-34
V
Valves, Pneumatic ......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..C-2

Index 3 (Index 4 blank)

 By Order of the Secretary of the Army:

GORDON R SULLIVAN
General, United States Army
Chief of Staff

Official:

MILTON H. HAMILTON
Administrative Assistant to the
Secretary of the Army
03954

DISTRIBUTION:

To be distributed in accordance with DA Form 12-34-E, Block 0899,

requirements for TM 750-116.

*U.S. GOVERNMENT PRINTING OFFICE: 1994 - 300-421/82036

PIN : 012697-000