What was found
ON CLIMBOUT, APU OFF BOTH GEN ON, RECEIVED A SPIKE. LOST ALL ELECTRICAL PWR IN COCKPIT AND CABIN FOR A SPLIT SECOND. NO C/B POPPED, NO EQUIP LOSS. INSPECTED LT AND RT GEN HARNESS, NTF INSPEC ENG GEN AND BUSS TIE BREAKERS. NTF RAN GCU DIODE TEST, BATTERY TEST AND STB POWER TEST, ALL PASSED. REPLACED LT AND RT ENG GCU. A/C PWR CKS NORMAL. GCU NR 1 (S/N ZG623) OFF. GCU NR 2 (S/N ZB3038DH) OFF.