As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: FOUND EMERERGENCY SYSTEM EMERGENCY POWER SUPPLY UNIT ON THE FORWARD LEFT WITH A FAULT 33-51-38 WHILE PREPARING FOR OVER-WING SLIDE REPLACEMENT. REMOVED AND REPLACED EMERGENCY POWER SUPPLY UNIT PER AMM 33-51-38.