My samsung un75f8000AFXZA power led is blinking twice 5 times

While wacthing tv in my samsung un75f8000 AFXZA, version US02 suddenly the screen went black and the power led started to blink twice , 5 times, repeatedly. No answer to the power button nor when unplugging or plugging. When pluged, the power led starts to blink and a switching sounds every 15/20 seconds. What is wrong with it? Attached pictures: