As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DURING R1 DOOR SLIDE REPLACEMENT, EMERGENCY LIGHTING SYSTEM TEST FAILED PER JTASK CARD 26L00025010, STEP 10, FAULT EMERGENCY POWER SUPPLY UNIT 12WL RIGHT. REPLACED EMERGENCY POWER SUPPLY UNIT BATTERY AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK PER AMM 33-51-38-000-002A.