In some not so common cases the inverters can fail and short in a way that would prevent the TV from coming up as the power supply board would detect the shortage and turn itself off. If you doubt this is the case the simplest way to verify it is to disconnect the backlight inverter boards supply from the power, which would eliminate the shortage. If the TV comes up and stays on (without backlight, of course) then this is likely the problem. change inverter board.
flyatyou66, July 2014