As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A LINE MAINTENANCE NON-ROUTINE CHECK, THE EMERGENCY EXIT SIGN AT AFT SIDE ON UPPER DECK WAS FOUND TO BE INOPERATIVE. MAINTENANCE REPLACED THE BATTERY PACK. SYSTEM OPERATION WAS NORMAL AFTER THE BATTERY PACK WAS REPLACED. (2011-00630)