As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EMERGENCY POWER SUPPLY L4 M33407 CAPACITY FND LOW - ORIGINATED B Y EMP V903529 ON HAECO NR 9442561, SPEC NO.B777-33-3-7019. PERFORMED BY EMP V905416, REPLACED M33407 L4 EMERGENCY POWER BAT TERY AND C/O OPERATIONAL TEST, THE RESULT FND "NORMAL" AS PER AM M 33-51-06-960-802 REV 92.