What was found
AIRCRAFT WAS GROUNDED: WHILE PERFORMING FUNCTIONAL CHECK CABIN EMERGENCY LIGHTING FOUND THAT FAP LIGHT EMER P/B SWITCH FAILS TO ILLUMINATE L1 AND R1 DOOR WALL MOUNTED LIGHTS, CEILING LIGHTS AT ROWS 4 AND 12 AND SEATROW LIGHTS 1,2,5,9,10,14 AND 15. MAINTENANCE REPLACED EMEMRGENCY POWER SUPPLY UNIT 10WL PER AMM 33-51-38 AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK.