As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING MAINTENANCE COURTESY CHECK FOUND EMERGENCY LIGHTS IN CENTER CABIN WOULD NOT ILLUMINATE. THE AIRCRAFT WAS REMOVED FROM SERVICE. TROUBLESHOT AND FOUND NR 3 EMERGENCY POWER SUPPLY UNIT BATTERY INOPERABLE. REMOVED AND REPLACED THE NR 3 EMERGENCY POWER SUPPLY UNIT BATTERY AND CHARGER IAW WC 33-002. THE OPERATIONAL CHECK WAS GOOD. NO FURTHER DEFECTS NOTED. THE AIRCRAFT WAS RETURNED TO SERVICE.