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 INSPECTION, MAINTENANCE REPORTED A PORTION OF THE EMERGENCY EVACUATION LIGHTING SYS WOULD NOT TEST. MAINTENANCE R & R THE APPROPRIATE POWER SUPPLY BATTERY PACK AND MADE ALL REQUIRED CORRECTIONS AND OPS CHECK WAS ACCOMPLISHED IAW AMM 33-50-00, SYS OPS CHECK WAS NORMAL. THE ACFT HAS BEEN RETURNED TO SERVICE.