What was found
ON TAXI OUT, NR 2 GENERATOR FAULT CAME ON. GENERATOR NR 2 WAS UNABLE TO RESET. PROCEDURE CALLED FOR NR 2 BUSS TO BE POWERED BY APU. ON T/O APU MOMENTARILY DROPPED OFF NR 2 CAUSING SPOILER FAULT LIGHTS, PITCH TRIM, YAW DAMP, WINDOW HEAT ETC TO TRIP OFF. T/O WAS ABORTED AT 80KTS, ALL ITEMS EXCEPT GENERATOR WERE RE-RESETABLE. REMOVED AND REPLACED GCU IAW M/M 24-22-12, PG 401. RAN IAW JRH, NR 2 GENERATOR OPS CHECKS GOOD. APU GENERATOR OPS CHECKS GOOD.