As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CEILING EMERGENCY LIGHTS NEXT TO THE R4 DOOR AND AFT GALLEY AISLE, CEILING DID NOT PASS A TEST, REMAINS OFF. ACCOMPLISHED TROUBLESHOOTING IAW 33-51-00. FOUND A DEFECTIVE BATTERY PACK IN THE EMERGENCY POWER SUPPLY UNIT M33409. REPLACED THE BATTERY PACK IAW AMM 33-51-06.