One of the chips is overheating. Use freeze spray to identify it, unsolder the heat sink, clean well, then use a good heat sink paste and resolder the heat sink back on. You can try turning the backlight down in picture settings as well. Menu-picture-Backlight. It is factory set at 100. Try turning it down to 50, then bump it up by 5 until the picture blinks. Bump it down 10 or 20 from there.