What was found
EMERGENCY LIGHTS ON RIGHT SIDE INOPERABLE. 2 RIGHT SIDE EXTERIOR OVER WING, RIGHT SIDE SHARK LIGHT, INTERIOR LAV OVERHEAD AND EXIT LIGHTS, AFT FLOOR LIGHTING, RIGHT SIDE AFT READING LIGHT ALL INOPERABLE. APU WAS RUN FOR 1/2 HOUR AND NO CHANGE TO STATUS. CORRECTIVE ACTION: FOUND NR 4 BATTERY PACK AND NR 3 BATTERY PACK INOPERATIVE. TRIED CHARGING BATTERY PACKS WITH SHIP POWER, BATTERY PACKS WILL NOT HOLD CHARGE. REMOVED AND REPLACED NR 4 BATTERY PACK, IAW 680 MM CH33-50-10. NOW EMERGENCY LIGHTS OPERATE WITH SWITCH IN ARM AND ON POSITION. NR 4 BATTERY PACK OPERATIONAL CHECKS GOOD. ACCESSED NR 3 BATTERY PACK FOR REMOVAL WITH PARTS ARRIVE. NR 4 BATTERY PACK REMOVED PN CBS28-1 SN 5795M INSTALLED PN CBS28-1 SN 5104M. REPLACED NR 3 BATTERY PACK P/N CBS28-1 S/N 568M WITH REPAIRED EMERGENCY BATTERY PACK P/N CBS28-1 S/N 1038M. ACCESSED AND REMOVED NR 2 BATTERY PACK P/N CBS28-1 S/N 5623. INSTALLED REPAIRED BATTERY PACK P/N CBS28-1 S/N 006338. ALL EMERGENCY LIGHTS OPERATIONS CHECK GOOD IN ARM AND ON POSITIONS WITHOUT AIRCRAFT POWER APPLIED.