As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING MX INSPECTION THE MAIN DOOR EMERGENCY LIGHT AND EXIT MARKER WERE NOT COMING ON. MX REMOVED AND REPLACED #1 EMERGENCY LIGHT BATTERY OPS CHECK FAILED NO FIX. MX TROUBLESHOOT FURTHER AND R/R EMERGENCY LIGHT SYSTEM INVERTER WITH OPERATIONAL CHECK GOOD. A/C WAS APPROVED FOR RETURN TO SERVICE.