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, MX REPORTED A PORTION OF EMERGENCY EVACUATION LIGHTING SYSTEM WOULD NOT TEST. MX R & R APPROPRIATE BATTERIES IN THE POWER SUPPLY AND MADE ALL REQUIRED CORRECTIONS AND OPS CHECK WAS ACCOMPLISHED IAW AMM 33-50-00, SYS OPS CHECKED NORMAL. ACFT RETURNED TO SERVICE.