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 250 of 828

TM 9–2350–311–20–2

3–138

3–3

TROUBLESHOOTING — CONTINUED

j.

NBC SYSTEM CIRCUIT — CONTINUED

(7)

NBC CONTROL BOX ASSEMBLY INDICATOR

LIGHT ILLUMINATES, BUT ASSISTANT GUN-

NER’S M3 ELECTRICAL HEATER DOES NOT

OPERATE. —

CONTINUED

CONTINUED FROM STEP B

yes

no

C

END OF TASK

Replace J2 connector

on NBC control box as-

sembly (para

17–4).

Repair wire 10 (para

17–4).

+

–

PIN C

J2 CONNECTOR

WIRE 10

yes

no

Repair wire 136C of NBC

power lead assembly

(para 8–9).

1.

Reconnect wire 136C to assistant gunner’s

M3 electrical air heater.

2.

Place one multimeter lead in socket C and

other lead to pin C of J2 connector of NBC

control box assembly.

3.

Check for continuity.

Is continuity present?

J2 CONNECTOR

SOCKET C

C