What was found
DURING TRANSIT CHECK, THE EMERGENCY LIGHT TURNED ON. MAINTENANCE PERSONNEL PERFORMED REVISION DETECTING THE ROWS 27 TO 33 LIGHTS TURNED OFF AND THE EMERGENCY LIGHT FAILURE CODES 33-12120, 33-12129 AND 33-12107 AND DURING THE APPLICATION OF TROUBLESHOOTING PROCEDURE AND FIM DMC-B787-A-33-50-F1-W2A-421A-A PROCEDURE, IT WAS DETECTED THAT CONTROL UNIT M5 RPDU 42 NOT EFFECTED THE RELEASE OF THE EMERGENCY LIGHTS; SO THE WIRELESS EMERGENCY SYSTEM CONTROL UNIT AND POWER MODULE M5 RPDU 42 IAW AMM DMC-B787-A-33-51-07-01A-520A-A AND AMM DMC-B787-A-24-71-05-00A-520A-A, TESTED CORRECT.