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 262 of 1275

TM 9-2350-311 -20-1

3-3

TROUBLESHOOTING CHART —

CONTINUED

m. ALTERNATOR CIRCUIT (M109A2/M109A3) —

ALTERNATOR FAILS TO CHARGE BATTERIES; GAGE

CONTINUED

INDICATION: NOT CHARGING, UNSTEADY OR

INACCURATE READING — CONTINUED

CONTINUED FROM STEP H

1. Reconnect powerplant wiring harness to

alternator.

2. Disconnect powerplant wiring harness from

rectifier.

3. Place jumper wires from pin E (lead 3)

to battery negative terminal and pin D

(lead 1) to the positive terminal of the

same battery to apply 12 Vdc to the

alternator field.

4. Turn MASTER switch ON and run vehicle

engine at idle speed (750 rpm).

5. Set multimeters on ac scale, and place red

lead of multimeter on pin A (lead 500) and

black lead on pin B (lead 501).

6. Check for voltage.

7. Place red lead of multimeters on pin C (lead

502) and black lead on pin A (lead 500).

8. Check for voltage.

9. Turn MASTER switch and engine OFF.

Is voltage above 27.5 Vat?

I

I

Repair or replace leads 500,501,

and/or 502 of powerplant wiring

harness (para 8-43).

CONTINUED ON NEXT PAGE

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