Same issue and the repair is 400 to 1000 bucks. Tv is 2 years old and junk. Samsung will not even acknowledge any issue and the moment I question them in any way they stop communicating. I will never buy a Samsung product again.
This is super disheartening to hear. Have had mine longer than most (2014) but thi ls issue just started out of no where and researching it im just seeing YEARS of forums and YouTube vids and lawsuits about it and NO fixes.
My tv is doing the same thing when I try to turn it on. Just cycles on and off. Doesn't stay on for mor than about one second. I replaced the Power supply board and also the main board. No improvement, same symptoms. Just about out of ideas. Could the screen itself cause this? Model number is UN49KS8500FXZA Version # FA01
If I disconnect the connector on the main board that comes from the power supply board the screen light stays on and power does not cycle on and off but of course there is no picture or sound. Just a backlit screen. Soon as I put that connector back on it starts power cycling.