Power Supply Board BN44-00441A I46F1-BHS FOR for 46" LA46D560F9T LN46D503F6FXZA
LN46D503F6FXZA HK02. disconnect the cable between the power board and the mainboard. plug your TV into a wall, if the backlight turns on then your power board is good. if it doesn't you either have a power board or a backlight issue.