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 238 of 828
TM 9–2350–311–20–2
3–126
3–3
TROUBLESHOOTING — CONTINUED
j.
NBC SYSTEM CIRCUIT — CONTINUED
(2)
NBC SYSTEM DOES NOT OPERATE.
—
CONTINUED
1.
Place one multimeter lead on terminal B of circuit
breaker CB1 and other lead on terminal 2 of
switch S1.
2.
Check for continuity.
Is continuity present?
1.
Place one multimeter lead at terminal A of circuit
breaker CB1 and other lead at input side of J1
connector on NBC control box assembly.
2.
Check for continuity.
Is continuity present?
CONTINUED ON NEXT PAGE
yes
no
C
Repair wire 1 (para 17–4).
yes
no
D
Replace circuit breaker
CB1 (para 17–4).
yes
no
E
Repair wire 3 (para
17–4).
CONTINUED FROM STEP B
TERMINAL A
CIRCUIT BREAKER CB1
TERMINAL B
–
+–
+
–
SWITCH S1
TERMINAL 2
WIRE 3
TERMINAL B
CIRCUIT BREAKER CB1
NBC CONTROL
BOX ASSEMBLY
WIRE 1
+
J1 CONNECTOR
INPUT
CIRCUIT
BREAKER
CB1
TERMINAL A
Back to Top
