As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING OVERNIGHT MAINTENANCE DISCOVERED EMERGENCY POWER SUPPLY UNIT ON THE LT SIDE BETWEEN ROW 10 AND 11 FAILED EMERGENCY LIGHT TEST. MAINTENANCE REMOVED AND REPLACED THE EPSU IAW SRM 33-51-38, OP CHECKS GOOD. CONFIRMED FAILURE. REPLACED S1 PUSH TO TEST SWITCH. REPAIRED AND TESTED IAW CMM 33-51-12-REV. 3.