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 134 of 828

TM 9–2350–311–20–2

Change 2

3–25

b.

CANNON — CONTINUED

(5)

PRIMER DOES NOT FIRE.

INITIAL SETUP

Tools

Artillery and turret mechanic’s tool kit

(SC 5180–95–CL–A12)

References

TM 9–2350–311–10

1.

Install firing pin (TM 9–2350–311–10).

2.

Disassemble firing mechanism and replace

unserviceable parts (para 5–2 or 5–3).

3.

Reassemble firing mechanism (para 5–2 or

5–3).

4.

Install and test firing mechanism

(TM 9–2350–311–10).

Does firing mechanism function properly?

1.

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

2.

Remove firing pin and inspect it for mushrooming,

breakage, or burrs (TM 9–2350–311–10).

3.

Inspect firing pin functioning orifice at the

obturator for powder fouling (burned-on carbon

deposits that may restrict firing pin movement)

(TM 9–2350–311–10).

Are burned-on carbon deposits that may restrict firing pin

movement present or is firing pin damaged?

Follow misfire instructions before opening

breechblock (TM 9–2350–311–10).

A

yes

no

Clean restricted firing pin

(TM 9–2530–311–10).

Replace firing pin as nec-

essary and verify fault is

corrected.

B

CONTINUED ON NEXT PAGE

yes

no

Replace firing mechanism

(TM 9–2350–311–10) and

verify fault is corrected.

WARNING