TM-9-2350-311-20-1

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

TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR HULL, POWERPLANT, DRIVE CONTROLS, TRACKS, SUSPENSION, AND ASSOCIATED COMPONENTS

AUGUST 1994

TM-9-2350-311-20-1 - Page 450 of 1275

TM 9-2350-311 -20-1

3-3 TROUBLESHOOTING CHART — CONTINUED

af. VENTILATED FACE PIECE SYSTEM CIRCUIT —

(5) AIR PURIFIER, DRIVER’S AND CANNONEER NO. 2

CONTINUED

NBC HEATERS FAIL TO OPERATE — CONTINUED

CONTINUED FROM STEP B

I

C

1.

2.

3.

4.

5.

Reconnect lead 438 to NBC switch.

Disconnect lead 438 from circuit breaker

output.

Place red lead of multimeter on circuit

breaker output and black lead to ground.

Turn MASTER switch ON and check for

voltage.

Turn MASTER switch OFF.

Is voltage present?

I

Repair or replace lead 438 of NBC

switch-to-circuit breaker lead assembly

(para 8-86).

D

1. Reconnect lead 438 to circuit breaker output.

2. Disconnect lead 10 from circuit breaker input.

3. Place red lead of multimeter in lead 10

and black lead to ground.

4. Turn MASTER switch ON and check for

voltage.

5. Turn MASTER switch OFF.

Is voltage present?

I

I

Replace circuit breaker (para 8-34).

I

I

Repair or replace lead 10 of power

lead assembly (para 8-56).

END OF TASK

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