As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DR 4R EMERGENCY LIGHT POWER PACK M33408 LOW VOLTAGE,REFER HAECO NON-ROUTINE LP:9478580,ORIGINATED BY EMP V905389,SPEC NO.B777-33 -3-7019. PERFORMED BY EMP V905389,REPLACED DR 4R M33408 EMERGENCY LIGHT B ATTERY PACK AND PERFORMED TEST OF THE NEW BATTERY PACK AS PER AM M 33-51-06-960-802 REV 94 TEST RESULT NORMAL. IDT BY EMP V905389 .