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, MX REPORTED A PORTION OF THE EMERGENCY EVACUATION LIGHTING SYS WOULD NOT TEST. MX R & R POWER SUPPLY BATTERY PACK AND OPS CHECKED IAW AMM 33-50-00, SYSTEM OPS CHECKED NORMAL. ACFT RETURNED TO SERVICE.