What was found
AIRCRAFT WAS GROUNDED: WHILE PERFORMING AMM TASK 33-51-00-040-001-A FOR MEL 23-26A TEST FAULT AT SEAT 26,27,30,31,35,&36 LEFT AND RIGHT AFT #4 MAIN CABIN DOOR AND 28 AND 36 CENTER CEILING PANEL EMERGENCY LIGHTS. MAINTENANCE REPALCED EMERGENCY POWER SUPPLY UNIT 13WL PER AMM 33-51-38 AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK.