TM-9-2350-311-20-2

HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5

TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR CAB, ARMAMENT, SIGHTING AND FIRE CONTROL, ELEVATING AND TRAVERSING SYSTEMS AND ASSOCIATED COMPONENTS

DECEMBER 1993

TM-9-2350-311-20-2 - Page 225 of 828

TM 9–2350–311–20–2

3–113

CONTINUED FROM STEP L

yes

no

M

CONTINUED ON NEXT PAGE

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DRIVER’S CONTROL BOX

1.

Reconnect cable CX9640 at driver’s control box.

2.

Disconnect driver’s mic/headset from control

box.

3.

Connect mic/headset to a control box that is

operating properly.

4.

Turn MASTER and amplifier AM 1780/VRC

POWER switches to ON.

5.

Operate mic/headset.

Does mic/headset operate properly?

Replace mic/headset.

1.

Turn MASTER and amplifier AM 1780/VRC

POWER switches to OFF.

2.

Place control box MONITOR switch to ALL and

VOLUME to maximum.

3.

Disconnect cable CX4723 from J801 or J804

connector.

4.

Place one multimeter lead in socket L of J801 or

J804 connector and other lead to pin B of J802

connector.

5.

Check for continuity.

Is continuity present?

N

NOTE

The following checks must be made on J801

and J804 connectors.

yes

no

Replace control box (para

8–16).

J802 CONNECTOR

PIN B

J801 OR J804

CONNECTOR