As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAINTENANCE COMPLETED SLIDE INSTALLATION UP TO STEP 6A, FOUND CIDS FAULT DURING TEST, LT FWD EMERGENCY POWER SUPPLY UNIT. REPLACED 11WL EMERGENCY POWER SUPPLY UNIT IAW AMM 33-51-13-401. OPERATIONS CHECKED OF EMERGENCY LIGHT SYS IAW AMM TASK 33-51-00-710-001-1 OK.