What was found
THE MAINTENANCE TEAM DISCOVERED DURING PREFLIGHT CHECKS THAT THE APU FIRE LED LIGHT WAS INOP DURING APU FIRE TEST. THE SYSTEM FAULT WAS DEFERRED UNDER MEL 49-20-01 AND OPERATIONS WERE CONTINUED UNTIL MAINTENANCE COULD BE SCHEDULED. THE MAINTENANCE PROVIDER TROUBLESHOT THE FIRE CONTROL SYSTEM AND REPLACED THE APU MNTR PCB (NZ026) WITH A NEW CONDITION PCB. OPS CHECKS GOOD, APU FIRE DETECT TEST AND APU FIRE SWITCH LIGHT TEST GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE