As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A ROUTINE OVERNIGHT SERVICE CHECK LAS VEGAS MAINTENANCE REPORTED THAT THE TAIL CONE AREA EMERGENCY LIGHTS WOULD NOT TEST. THEY FURTHER REPORT THE REPLACEMENT OF THE BATTERY PACK AT POWER SUPPLY B5-28. A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED PER AMM 33-53-00. THE AIRPLANE HAS RETURNED TO SERVICE.