f42k20e tv turned on normally after about 40 minutes screen froze--no response to remote at all--tryed manual power button no response---unplugged tv for 5 minutes--plugged back in---manual power button push caused power led to go from red to purple then flash purple 3 times---remote does nothing---power supply board failed before in tv was replaced---visual inspection of power supply board shows no obvious defects(no bulged caps as before no scorch marks)