**Summary**: I've changed the main board, Power Supply board still no display for the exact same model.
Should I attempt to change the T-CON board??
I'd called a Samsung authorized technician for in-house diagnostic (charged me $70), he was no help at-all, he unplugged few connectors, replaced the power supply board with one he was carrying and finally after 10 mins said its the main board issue and need to be replaced. In his paper work he was not willing to mentioned that the main board is the problem, that shows he was not confident.
I went ahead and ordered the main board and tried it out today and it also does not seems to fix the issue, I still see red blinking red light, my samsung UN55D60000SFXZA is 2 yr old, bought it from best buy.
I'm not sure should I consider it a loss and trash the TV or try to replace few more parts hoping it will fix it.
Samsung technician should have more diagnostic tool set.
My 2 year old LED/LCD is no longer showing a picture. Only seeing a red blinking light in lower right corner. Unsure if I should replace power supply board or another board. Seeking help diagnosing problem.