As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER BLOCK IN AND POWER TRANSFER TO GPU NOTICED BURNING ELECTRICAL SMELL. EICAS MESSAGE "L BUS ISOLATED". CIRCUIT BREAKER "BAT 1 R SIDE PNL" IS OUT. REMOVED AND REPLACED LEFT GENERATOR CONTROL UNIT IAW AMM 24-22-02-4. OPS CHECK GOOD. REF WRI 24-00/0476 FOR ELECTRICAL POWER PANEL REPLACEMENT.