When I turn on the tv the lg symbol comes on for about a tenth of a se

When I turn on the tv the lg symbol comes on for about a tenth of a second. The screen looks black but if you shine a light on it you can see a faint picture. Is it the backlight or inverter? Its a lg 55 ln5600 and is the power supply and the inverter on the same board and where can I buy the power supply / inverter