Chosen Solution
We have a Toshiba flat screen LCD that constantly blinks – goes dark for a half second like the LEDs are turning on or off. Changing the picture mode can alter the rate of blinking but I cannot get it to stop altogether (although this has worked in the past). Any suggestions on how to fix this?
@alf222 let us know the exact model of your TV. If it is the screen that is blinking it is possible that you have a bad power board/LED driver or a bad LED array. Post some good images of all of your boards with your question so that we can see what you see. Use this guide Adding images to an existing question for that.
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.
