Display flashes in and out

Gerard Bernasconi since it blacks out even with no input it sounds like either you are losing the backlight or the power to the panel. On your boards, check the cables on connector CN101 ↔ CN801 which supplies main power from IP board to main board and CN1102L ↔ CN1805 which supplies dimming power from IP board to main board. right now I'd be looking at the IP board (power board) as the culprit. The Samsung part number for that is BN44-00202A. So take a close look at the board to see if there is any obvious damaged part. Post images of your board with your question so we can see what you see. For that use this guide. currently there are some issues with the way ifixit post links, so just click on the black rectangle that says "Adding images to an existing question". They are looking into the cause for the supersized links :-)