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 237 of 828

TM 9–2350–311–20–2

3–125

j.

NBC SYSTEM CIRCUIT — CONTINUED

(2)

NBC SYSTEM DOES NOT OPERATE.

INITIAL SETUP

Applicable Configuration

M109A4/M109A5 howitzers

Test Equipment

Multimeter (item 6, Appx H)

Tools

Artillery and turret mechanic’s tool kit

(SC 5180–95–CL–A12)

Equipment Condition

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

CAB NBC POWER switch to OFF (TM 9–2350–311–10)

1.

Disconnect wire 100 from J1 connector on

bottom of NBC control box assembly.

2.

Turn MASTER switch to ON.

3.

Place red multimeter lead in wire 100 and

black lead to ground.

4.

Check for voltage.

Is battery voltage present?

Troubleshoot contact arm

assembly (para 3–3g.).

yes

no

A

B

yes

no

Replace J1 connector (para

17–4).

CONTINUED ON NEXT PAGE

NBC CONTROL BOX ASSEMBLY

+–

1.

Turn MASTER switch to OFF.

2.

Place one multimeter lead on output side and

other lead to input side of J1 connector on NBC

control box assembly.

3.

Check for continuity.

Is continuity present?

J1 CONNECTOR

INPUT

J1 CONNECTOR

OUTPUT

J1 CONNECTOR

WIRE 100

+

–