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 228 of 828

TM 9–2350–311–20–2

3–116

i.

INTERCOMMUNICATION SYSTEM

— CONTINUED

(4)

OPERATOR CANNOT COMMUNICATE AT GUN-

NER’S OR COMMANDER’S CONTROL BOX.

INITIAL SETUP

Test Equipment

Multimeter (item 6, Appx H)

Tools

Artillery and turret mechanic’s tool kit

(SC 5180–95–CL–A12)

Equipment Condition

Amplifier AM 1780/VRC POWER switch to OFF

(TM 9–2350–311–10)

Vehicle MASTER switch to OFF (TM 9–2350–311–10)

1.

Disconnect operator’s mic/headset from control

box.

2.

Connect mic/headset to a control box that is

operating correctly.

3.

Turn MASTER and amplifier AM 1780/VRC

POWER switches to ON.

4.

Operate mic/headset.

Does mic/headset operate properly?

yes

no

A

Replace mic/headset.

1.

Turn MASTER and amplifier AM1780/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?

NOTE

The following checks must be made on

connectors J801 and J804.

B

CONTINUED ON NEXT PAGE

+

–

J801 OR J804

CONNECTOR

SOCKET L

J802

CONNECTOR

PIN B