What was found
DURING CRUISE L GEN DROPPED POWER (ON ELECTRIC SYNOPTIC PAGE) AND L MAIN AC BUS WAS NOT POWERED INTERMITTENTLY. R/I 03AUG21 13:10 CGN U REASON CODE : PREMATURE REMOVAL/INSTALLATION OFF MPN: 756603E POS: P1 SRL: AAA3002714 TAG NBR: 14G788 ON MPN: 756603F CPN: 2413479 SRL: AAA3005031 TAG NBR: 787H36 FACT 03AUG21 13:10 CGN U FOUND MX-MSG: 24-11786. PERFORMED TS AS PER FIM 24-51-00-2-0 TASK 24-51-00-810-833 AND RELOADED ELMS SOFTWARE IN SIU#2(P110) (BOTH CHANNELS) AS PER AMM 24-09-00-2-2. VERIFIED CORRECT SOFTWARE PN. RELOAEDED SOFTWARE INTO BPCU AS PER AMM 24-41-05-2. VERIFIED CORRECT PN INSTALLED. PRECAUTIONARY REMOVED AND REPLACED LH GCU AS PER AMM 24-22-02-4. VERIFIED CORRECT SOFTWARE PN. PERFORMED OPERATIONAL CHECK OF THE AC SYSTEM PER AMM 24-22-00-5 DURING ENGINE RUN. NO DEFECTS NOTED. NO ACTIVE FAULTS. FACT 08AUG21 00:44 IND REMOVED & REPLACED LEFT GCU & OP`S CHECKED REF FDX B777 AMM 24-22-02-4. & FDX B777 JRH. OK FOR SERVICE.