The TV has a chip that check to see if the circuits are OK before turning on the set. Samsung has a power, input (control) and video boards. The problem is when it check the high voltage circuit and it does not have 390 volts, the chip turn-off the power instead. You can buy a new power board or fix it yourself. The power board is where the 120 volts AC is plugged in, and near the 120 volts is small transformer, then you will see a capacitor rated 100 uf at 450 volts. Check for 390 volts here. If the voltage is less, then replace this capacitor with a 350 uf at 400 or at 450 volts.Samsung used a "small" capacitor when it should have ordered at large capacitor. Good luck.