What was found
AFTER NR 2 ENG START IN AUS, THE APU GEN DISCONNECTED FROM BOTH B USES WHEN NR 2 ENG GEN CONNECTED. APU GEN WOULD NOT CONNECT TO ANY BUS AFTER THAT. THERE WAS A STRONG ELECTRICAL ODOR DURING T HIS EVENT. T/S AND FOUND APU GCU AT FAULT, WITH A GCU FAULT LIGHT AND ELECTRICAL ODOR. R&R SAME REF AMM 24-21-81. OPS CHECKS NORMAL. ROTABLE PARTS CHANGE WAS INDICATED - TT # 1439840 S/N OFF 02993 UNIT, GENERATOR OFF 29-2421-9-0002 2993 O/N 29-2421-9-0002 2992.