TROUBLESHOOTING (Continued)

TM 9-4910-663-34 MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION If both voltages are zero, replace transformer T3; if voltage at terminals H1 and H4 is normal, but zero voltage is obtained at terminals X1 and X4, replace transformer T4. 10. STARTER TEST CIRCUIT a. STARTER TEST CIRCUIT INOPERATIVE WHEN PERFORMING TEST OF EXTERNAL COMPONENTS. Step 1. Check to see that CIRCUIT BREAKERS CB2 DRIVE CONTROL, CIRCUIT BREAKERS CB5 RELAY CONTROL, CIRCUIT BREAKERS CB7 AC VAR. VOLTS, and CIRCUIT BREAKERS CB9 DC VAR. VOLTS circuit breakers are all set to ON position. Set circuit breaker switch CB1 to OFF position. Connect a test lead from positive (red) DC VARIABLE VOLTS OUTPUT binding post to STARTER FREE RUN binding post, and connect another test lead from negative (black) DC VARIABLE VOLTS OUTPUT binding post to STARTER COM binding post. Set AMMETER LOAD & STARTER OUTPUT CURRENT BATTERY CHARGE CURRENT RANGE switch S14 to STARTER FREE RUN X4 position. Set DC VOLTMETER OUTPUT VOLTAGE SELECT switch S11 to VAR position, and DC VOLTMETER OUTPUT VOLTAGE RANGE switch S12 to X2 position. Rotate STARTER RHEOSTAT control R18 clockwise until it is snug. Set circuit breaker switch CB1 to ON position. Set DC VARIABLE VOLTS switch S10 to ON position and adjust DC VARIABLE POWER SUPPLY 0-32 VDC control as required to provide 10 volt indication on DC VOLTMETER OUTPUT VOLTAGE meter M2. Set LOAD SELECTION 25 AMPS/12.5 AMPS switch S23 to ON position, set STARTER TEST switch S9 to ON position, and check to see that indication of approximately 6 amperes in the reverse direction is obtained on DC AMMETER LOAD & STARTER OUTPUT CURRENT BATTERY CHARGE CURRENT meter M3. If no current indication is obtained, proceed to step 2. Step 2. Set DC VARIABLE VOLTS switch S10 to OFF position. Disconnect test leads at STARTER FREE RUN and STARTER COM binding posts. Using ohmmeter, check for continuity across contacts of relay K8. 2-42