As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: BUILT IN TEST EQUIPMENT TEST FOR EMERGENCY LIGHTS REPORTS EMERGENCY POWER SUPPLY UNIT INTERNAL LOAD EMERGENCY LEFT FAULT. REMOVED AND REPLACED 10WL EMERGENCY POWER SUPPLY UNIT AND BATTERY (AALA202111153502). REMOVED AND REPLACED 13WL EMERGENCY POWER SUPPLY UNIT (AALA202111152527) AND BATTERY (AALA202111159246). REMOVED AND REPLACED BATTERY (AALA202111150299) ON 12WL EMERGENCY POWER SUPPLY UNIT. ALL REQUIRED OPERATIONS TESTS PASS. PER TSM 33-51-00-810-807-A. NO FAULTS AT THIS TIME. OK FOR SERVICE.