TROUBLESHOOTING (Continued)

TM- 9-4910-663-34 Table 2-5. TROUBLESHOOTING (Continued) MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION If coil resistance is not within specified limits, replace relay K5. Step 6. Reconnect lead disconnected in step 5. With circuit breaker switch CB1 set to OFF position, check for continuity across appropriate terminals (fig 2-4) of POLARITY REVERSING switch S7 with switch set to NEG GND position. Replace switch S7 if open indication is obtained. 6. LOAD BAND CIRCUIT a. LOAD BANK CIRCUIT INOPERATIVE OR OPERATES ERRATICALLY DURING TESTING OF EXTERNAL COMPONENTS. Step 1. Set all LOAD SELECTION switches to OFF position. Set DC AMMETER LOAD & STARTER OUTPUT CURRENT BATTERY CHARGE CURRENT RANGE switch S14 to LOAD X1 position. Connect ohmmeter between REGULATOR B± and REGULATOR B-binding posts. Check to see that circuit breaker switch CB1, CIRCUIT BREAKERS CB2 DRIVE CONTROL circuit breaker, and CIRCUIT BREAKERS CB5 RELAY CONTROL circuit breaker are all set to ON position. Set MASTER LOAD DISCONNECT switch S8 and LOAD SELECTION 0-25 AMPS/0-12.5 AMPS switch S24 to ON position. Check ohmmeter indication as VARIABLE LOAD control R32 is rotated from fully counterclockwise setting to fully clockwise setting. Resistance should vary between 46.1 ohms ±5% and 1.14 ohms ±5%. If ohmmeter indicates open circuit, proceed to step 2; if indication is normal, proceed directly to step 9. Step 2. Using ohmmeter, check for 1.14 ohm ±5% indication between REGULATOR B-binding post and load bank terminal 19. If resistance is not as specified, replace load bank element. Step 3. Using ohmmeter, check resistance between center terminal of rheostat R32 and terminal with lead. Resistance should be variable between 0 and 45 ohms. 2-26