What was found
(RECURRING PROBLEM): DURING TAKEOFF, THE F/A NOTICED THE EMERGENCY LIGHTS FLICKERED. GROUND MX CREW R & R THE EMERGENCY LIGHTS SWITCH. OPS CHECK WAS PERFORMED SATISFACTORY. ACFT RELEASED TO FLIGHT STATUS. ACFT FLEW AND UPON LANDING, THE F/A NOTICED AGAIN THE EMERGENCY LIGHTS FLICKERED. GROUND MX CREW R & R THE EMERGENCY LIGHTS CONTROL BOX, ACFT WAS RELEASED FOR A TEST FLIGHT FOR THE OPS CHECK. TEST FLIGHT WAS PERFORMED SATISFACTORY. ACFT WAS RELEASED FOR FLIGHT. ON TAKEOFF, THE F/A NOTICED THE EMERGENCY LIGHTS FLICKERED AGAIN. GROUND MX CREW R & R THE RT TRANSFORMER RECTIFIER UNIT, OPS CHECK OF THE EMERGENCY LIGHTING SYS CHECKED SATISFACTORY.