As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - EEL - DURING 8-DAY CHECK TEST OF EMERGENCY LIGHT SYSTEM FOUND THE LT FORWARD EMERGENCY POWER SUPPLY UNIT (10WL) INOPERATIVE. MAINTENANCE REMOVED AND REPLACED EMERGENCY POWER SUPPLY UNIT (10WL) AND BATTERY PACK, OPERATIONAL CHECK WAS GOOD.