TM 11-6625-1831-13
5-3b.
Troubleshooting Test Panel (Cont)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1. Resistance between POWER IN J4 pins low.
Step 1. Check for foreign object between pins of J4.
Remove foreign object.
Step 2. Check for foreign object on back side of J4 and CB1. Remove six screws and cover from back
of J4 and CB1.
Remove foreign object.
Step 3. Check for short circuit inside CB1. Remove wires from CB1 and check continuity from
terminals 2 to 4, 2 to 6, and 4 to 6.
If any reading is less than 1 megohm, replace CB1 (para 5-6).
Step 4. Check whether problem still exists.
Replace J4 jack (para 5-6).
2. Resistance between POWER IN J4 pins low.
Step 1. Check transformer T1 for short circuit. Remove wires from T1. Check resistance from
terminals 1 to 2, 1 to 3, 2 to 3.
If any reading is less than 30 ohms, replace T1 (para 5-6).
Step 2. Check relay K1 for short circuit. Remove wires from K1 terminals A2, B2 and C2 Measure
resistance from A2 to B2, A2 to C2, and B2 to C2.
If any reading is less than 1 megohm, replace K1 (para 5-6).
Step 3. Check for short circuit in wiring between CB1, K1 and T1
Repair as necessary (para 5-14).
3. Resistance between POWER IN J4 pins high.
Step 1. Check for open circuit breaker CB1 Remove six screws and cover from back of J4 and CB1
Turn on CB1 Check resistance between terminals 1 to 2, 3 to 4, 5 to 6.
If any reading is not zero ohms, replace CB1 (para 5-6).
Step 2. Check filters FL1, FL2, and FL3 for open circuit. Check resistance between the two terminals
of each filter.
If any reading shows open circuit, replace that filter (para 5-6).
Step 3. Check transformer T1 for open circuit. Remove wires from T1 terminals 1, 2, and 3 Check
resistance from terminals 1 to 2, 1 to 3, and 2 to 3.
If any reading shows open circuit, replace T1 (para 5-6).
Step 4. Check wiring between J4, CB1, FL1, FL2, FL3, and T1.
Repair as necessary (para 5-14).
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