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 135 of 828

TM 9–2350–311–20–2

3–26

Change 2

3–3

TROUBLESHOOTING CHART — CONTINUED

b.

CANNON — CONTINUED

(5)

PRIMER DOES NOT FIRE. — CONTINUED

1.

Perform misfire procedures

(TM 9–2350–311–10).

2.

Remove firing mechanism (TM 9–2350–311–10).

3.

Remove and check thread inside obturator

spindle nut for cross-threading caused by carbon

deposits (para 5–7).

Is obturator spindle nut cross threaded?

Attempt to fire (TM 9–2350–311–10).

If primer does not fire, is it indented?

CONTINUED FROM STEP B

C

yes

no

Notify chief of section or

chief of firing battery for

further instructions.

CONTINUED ON NEXT PAGE

D

1.

Replace obturator spindle nut (para 5–7).

2.

Install firing mechanism

(TM 9–2350–311–10).

3.

Attempt to fire (TM 9–2350–311–10).

Does primer fire?

E

yes

no

Go to step F.