Table 5-4. Troubleshooting - Continued

TM 9-4931-378-13&P

Table 5-4. Troubleshooting Continued

Malfunction

Test or Inspection

Corrective

Action

25. ONE OR MORE SEGMENTS MISSING FROM ANY DATA WD READOUT DIGIT.

Step 1. Perform voltage check in accordance with paragraph 5-12.e. (4).

Step 2. Disconnect connector P3 from underside of motherboard, set circuit breakers CB1 and CB2 OFF, and perform

continuity check of relevant circuits between connector PS and DS12P1, DS12P2, and/or DS12P3. (See

paragraph 5-14 and figure FO-1.) Reconnect connectors after continuity checks.

Repair wiring as necessary.

Step 3, Replace CCA 1A1.

Step 4. Replace DATA WD readout DS12.

26. CIRCUIT BREAKER CB2 FAILS TO LATCH IN THE ON POSITION.

Step 1. Check bench 28 Vdc supply.

Correct as necessary.

Step 2. Perform continuity/short circuit checks on dc input power lines. (See paragraph 5-14 and figure FO-1.)

Repair wiring as necessary.

Step 3. Check circuit breaker CB2.

Replace circuit breaker CB2.

27.28 VDC LAMP FAILS TO ILLUMINATE WHEN CB2 IS ON.

Step 1. Check 28 Vdc lamp.

Replace 28 Vdc lamp.

Step 2. Check circuit breaker CB2.

Replace circuit breaker CB2.

Step 3.

Check capacitor C1.

capacitor is defective, send test set to higher maintenance for repair.

Step 4.

Check capacitor C2.

capacitor is defective, send test set to higher maintenance for repair.

Step 5. Perform continuity check on dc input power lines. (See paragraph 5-14 and figure FO-1.)

Repair wiring as necessary.

28. ADS NO GO LAMP FAILS TO ILLUMINATE WITH CB2 ON.

Step 1. With S5 in SELF TEST, confirm all other lamps on front panel illuminate.

If lamps illuminate, proceed to step 2; if not, proceed to table 5-4,32.

Step 2. Check ADS NO GO lamp.

Replace ADS NO GO lamp.

Step 3. Perform continuity check of wiring between XDS11 and P3 (See paragraph 5-14 and figure FO-1.)

Repair wiring as necessary.

Step 4. Replace CCA 1A1.

29. LAMPS DS1 THROUGH DS11 AND DS13 NOT ILLUMINATED WITH S5 IN SELF TEST.

Step 1. With S11 in 28 Vdc, confirm 28 Vdc present at TP9 and TP10.

If present, proceed to step 3; if not, proceed to step 2.

Step 2. Check diode CR2.

Replace diode CR2.

Step 3. Perform continuity check of dc input power lines to XDS11 and XDS13. (See paragraph 5-14 and

figure FO-1.)

Repair wiring as necessary.

Step 4. Check lamps DSI through DS11 and DS13.

Replace lamps.

5-27