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I have a Similar issue except mine is not flashing.. I have replaced mainboard and t-con, still no audio or picture. It originally had vertical stripes that shifted from top to bottom.. took apart tv and disconnected everything and reconnected it back and lines were gone. I’m at a loss with this tv so far I’m about to trash
brandonleil024 let us know the exact model of your TV. Since you already changed the main and t-con board I would go through the trouble and measure the voltages on the power board going to the main board and see if they correspond with what is printed on the board. If your main board does not get what it needs your TV would display symptoms like you are describing. Most Samsungs will turn the backlight on when you disconnect the main board from the power board. Give that a try as well and let us know what you get with that. You can also post some pictures of your boards with your question which will let us see what you see. Adding images to an existing question
