As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSPECTION TYPE: N/A AT DEPARTURE, FLT CREW REPORTED THAT THE EMERGENCY ESCAPE SLIDE WARNING LIGHT AND HORN WOULD NOT TEST. DURING TROUBLESHOOTING FOUND THAT NR 2 SHIP BATTERY DISCHARGED WITH ONLY 1V. REMOVED AND REPLACED BATTERY. SYSTEM OPERATION CHECKED NORMAL.