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 652 of 828
TM 9–2350–311–20–2
17–14
Change 2
17–4 NBC CONTROL BOX ASSEMBLY — CONTINUED
b.
Disassembly
CAUTION
Remove cover carefully to prevent damaging wires or components attached to cover.
1
Loosen four captive screws (9) and carefully remove cover (10).
2
Tag and disconnect all wires.
NOTE
Nut (11) and washer (12) are part of indicator light (13). Retain parts for assembly.
3
Remove nut (11) and washer (12) from indicator light (13) and remove indicator light, lens (14), and LED
(15) from cover (10).
NOTE
Nut (17), washer (18), and locking tab (19) are part of toggle switch (20). Retain parts for assembly.
4
Lift switchguard (16) and remove nut (17), washer (18), and locking tab (19) to remove toggle switch (20),
switchguard, and packing with retainer (21) from cover (10). Discard packing with retainer.
5
Disassemble four screws (22), four lockwashers (23), and mounting plate (24) and carefully remove from
control box (25) with components attached. Discard lockwashers.
6
Remove two hex nuts (26), two machine screws (27), two lockwashers (28), two flat washers (29), and cir-
cuit breaker (30). Discard lockwashers.
7
Remove two hex nuts (31), two machine screws (32), lug terminal (33), two lockwashers (34), and electro-
magnetic relay (35). Discard lockwashers.
8
Remove four hex nuts (36), four lockwashers (37), four flat washers (38), four machine screws (39), J1 con-
nector (2), and gasket (40) from bottom of control box (25). Discard gasket and lockwashers.
9
Remove four hex nuts (41), four flat washers (42), lug terminal (43), four lockwashers (44), four machine
screws (45), J2 connector (5), and gasket (46) from side of control box (25). Discard gasket and lock-
washers.
c.
Repair
1
If control box (25), cover (10),
inside mounting plate (24), or mounting screws (9) are damaged, replace
distribution box (3).
2
If wires or lug terminals are damaged, replace with fabricated internal wires as necessary. Follow wiring
chart and wiring diagram (para 3–3j.) for fabricating internal wires. For lug terminal repair see para 8–1.
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