TV turning on and off with blinking red led

So my year and a half samsung TV qe55q60rat turning on and off in matter of seconds,the samsung logo showing up but after that black screen on turning off.

I have tried to plug the TV out of the wall for an hour but no luck,tried with no HDMI calbes but no luck.

The small red LED on the bottom of the TV blinking in a pattern, two quick blinks and one long blink. (three in total).

I checked the the power supply of the TV, I opened the back cover and the plug of the power supply to the main board I disconected and checked with multimeter and 12V 21W light bulb to see if the PSU can stand with some load and it did.

so is my problem in the main board or something else?