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: DONT WORK CORRECTLY EPSU-EMERGENCY POWER SUPPLY UNIT 14WL INCLUDING BATTERY IN PASSENGER CABIN. REPLACED EPSU-EMERGENCY POWER SUPPLY UNIT 14WL (AALA202409107071) INCLUDING BATTERY (AALA202409104806) IN PASSENGER CABIN IAW AMM 33-51-38-000-001-A AND AMM 33-51-38-400-001-A. PERFORMED BITE TEST, TEST IS OK IAW AMM 33-51-00-710-001-A.