What was found
SOURCE OFF LIGHT ON GEN 1 SIDE WHEN TRANSFERRING FROM GROUND POWER TO APU GEN. GROUNDED - YES. OMF SHOWS NO FAULTS, GCU & BPCU NO FAULTS, ELECTRICAL PANEL MODULE TEST NO FAULTS AMM 46-13-00, AMM 24-21-00, AMM 24-41-00, AMM 24-31-00, CYCLED A/C POWER WITH NO FIX AMM 24-41-00, TRIED NEW GCU #1 & BPCU NO FIX, RE-INSTALLED BOTH LRUS AMM 24-21-81/401 & AMM 24-41-21/401, ALSO ACCOMPLISHED IFIM 24-21-00-810-809, REPLACED NEW AC SYSTEM GENERATOR & APU MODULE & PERFORMED INSTALLATION TEST GOOD AMM 24-21-51/401.