As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS IN BASE MAINTENANCE: INOP EPSU-EMERGENCY POWER SUPPLY UNIT 10WL INCLUDING BATTERY IN PASSENGER CABIN. REPLACED EPSU-EMERGENCY POWER SUPPLY UNIT 10WL (AALA202403201415) INCLUDING BATTERY (AALA202403206119) IN PASSENGER CABIN.