TM 10-6640-239-13 4-12 Table 4-3.  Troubleshooting MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION WARNING Before  performing  any  maintenance  actions  on  electrical  equipment,  ensure  all electrical power has been turned off.  Failure to comply with this warning may result in serious injury or death. NOTE Refer  to  electrical  schematic  diagram  FO-1  located  in  the  back  of  the  manual when troubleshooting electrical system. 1. NO ELECTRICAL POWER TO LABORATORY, GENERATOR OUTPUT SWITCH ON AND POWER CABLE PROPERLY CONNECTED. WARNING Do not come in contact with main power cable connections on generator set with power applied to Mod Lab B.  Failure to comply with this warning may result in serious injury or death. Step 1.    Position generator set circuit breaker to open position. Step 2.    Disconnect generator and Mod Lab B power cables. Step 3.    Check power cable for open or shorted leads using multimeter. If open or shorted lead is found, replace power cable. 2. INDIVIDUAL FLUORESCENT LIGHT BULB FAILS TO ILLUMINATE AFTER STARTER REPLACEMENT. Step 1.    Replace ballast.  See paragraph 4-15. Step 2.    Replace switch.  See paragraph 4-22. Step 3.    Replace applicable circuit breaker.  See paragraph 4-18. 3. FORWARD OR REAR EMERGENCY LIGHT FAILS TO ILLUMINATE WHEN POWER FAILURE OCCURS. Step 1.    Replace ballast in appropriate ballast box.  See paragraph 4-16. Step 2.    Replace switch.  See paragraph 4-22. Step 3.    Replace applicable circuit breaker.  See paragraph 4-18. 4. NO POWER AVAILABLE IN PETROLEUM LABORATORY, PURGE CYCLE COMPLETED AND CIRCUIT BREAKER A1CB1 IN ON POSITION. Reset circuit breaker A1CB1. If power still not available, replace circuit breaker A1CB1.  See paragraph 4-18.