What was found
DURING ACCOMPLISHMENT OF B-CHECK WORK CARD 0617, DISCOVERED WHEN THE EMERGENCY LIGHTS WERE SELECTED TO THE ON POSITION, THE AFT EMERGENCY LIGHTS ABOVE THE TALL CONE SLIDE DID NOT ILLUMINATE. TROUBLESHOOTING PROCEDURES DETERMINED THE BATTERY POWER SUPPLY WAS AT FAULT. THE POWER SUPPLY WAS REPLACED AND THE SYSTEM WAS OPERATIONAL CHECKED IAW DC-9 MM 33-53-0 AND FOUND TO BE OK FOR SERVICE. (X)