What was found
CAPTAIN REPORTED THAT EMERGENCY LIGHTS WERE BLINKING DURING TAKEOFF; SO THE FLIGHT CREW TURNED ON THE SWITCH AND CONTINUING TO DESTINATION. MAINTENANCE PERSONNEL PERFORMED REVISION DETECTING THE ROWS 28 TO 33 LIGHTS TURNED OFF, DURING THE APPLICATION OF TROUBLESHOOTING PROCEDURE, IT WAS DETECTED THAT CONTROL UNIT WCU SHOWN WITH FOLLOWING CODES: 335 831 00 AND 335 832 00; SO IT WAS DEFERRED IAW MEL 33-51-02-01 CAT. C. AT MEX, WCU AND BATTERY UNIT IN SEAT 23 AND 33 WERE REPLACED IAW AMM DMC-B787-A-33-51-07-01A-520A-A/720A, OPERATIONAL TEST WAS ACCOMPLISHED IAW AMM DMC-B787-A-33-51-00-00E-320A-A, TESTED CORRECT.