As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
OPERATIONAL TEST FND L3 M33400 EMER POWER SUPPLY MALFUNCTION - O RIGINATED BY EMP V903529 ON HAECO 9445483, SPEC NO.B777-33-3-703 0. PERFORMED BY EMP V905416, M33400 EMERGENCY POWER SUPPLY CHARGER REPLACED AND EMERGENCY LIGHT SYSTEM OPERATIONAL TEST CARRIED OUT FOUND NORMAL AS PER AMM 33-51-00-710-802 REV 92.