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 241 of 828

TM 9–2350–311–20–2

3–129

j.

NBC SYSTEM CIRCUIT — CONTINUED

(3)

NBC CONTROL BOX ASSEMBLY INDICATOR

LIGHT ILLUMINATES, BUT M2A2 AIR PURI-

FIER 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 135 from M2A2 air purifier.

2.

Turn MASTER and CAB NBC POWER switches

to ON.

3.

Place red multimeter lead in wire 135 and black

lead to ground.

4.

Check for voltage.

Is battery voltage present?

Replace M2A2 air puri-

fier (para 17–3).

1.

Place one multimeter lead on one end of NBC

ground lead that connects to M2A2 air purifier

and other lead on NBC ground lead that

connects to M27 periscope.

2.

Check for continuity.

Is continuity present?

A

yes

no

Repair NBC ground lead

(para 8–10).

B

yes

no

CONTINUED ON NEXT PAGE

M2A2 AIR

PURIFIER

–+

GROUND LEAD

WIRE 135

–

+