Tv cycles on off with no picture but has sound

I have a 3 year old samsung tv UN70TU7000FXZC.

Power is good. Checked power board getting proper volts. Backlight works. Original symptoms is the tv cycles on off rapidly with no picture just sound. If I disconnect the ribbon going from main board to driver boards it will turn on and stay on with sound but no picture. If I reattach the ribbon the symptoms come back. If I detach either the left or right side ribbon on the driver boards I get the same result as when detaching the main board ribbon. I'm trying to narrow down what is causing the issue but i hit a wall. With all my test I haven't been able to get a picture back and I only can stop the on off cycle by removing the ribbon on the main board or 1 of the 2 from the driver board.