What was found
ETOPS - APU GENERATOR KICKED OFF AFTER GND POWER REMOVED, ATTEMPTED ONE RESET FAILED AGAIN. ACCOMPLISHED TSM 24-20-00-810-997-A, BITE TEST OF ECMU1 FAULTING MESSAGE BTC-1(11XU1) / ECMU1(1XM1). REMOVED AND REPLACED BTC-1 (11XU1) REF AMM 24-22-55-000-803 AND AMM 24-22-55-400-803, BITE TEST ECMU1 NIL HELP GIVING SAME MESSAGE. REMOVED AND REPLACED ECMU-1(1XM1) PER AMM 24-29-34-400-801. BITE TEST OK. RUN APU AND ENG #1 FOR 10 MINS, NO FAULTS NOTED.