As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT IN BASE MAINTENANCE: EMERGENCY POWER SUPPLY UNIT 12WL FAILS BITE TEST - REPLACED EMERGENCY POWER SUPPLY UNIT 12WL *AALA202610145116* AND BATTERY *AALA202610140963* - A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED WITH NO FAULTS NOTED