Tv turned itself off. turn power back on, picture

Your TV is experiencing a convergence issue as indicated by the 3 blinks. The only way to fix this is replacing the convergence ICs. It is not a hard task to replace these ICs. You just need to know how to solder and work on printed circuit boards.

The convergence ICs are mounted on a large heat sink and are marked with codes starting with the letters STK and there are two of them. You need to replace both.

Look for the heat sink with two ICs mounted on it and check the markings.

Once found, cut the IC legs with a small side cutter and unscrew it from the heat sink. Remove the legs left soldered on the board.

Take note of the IC markings for ordering the right part and how it was installed. Don't forget to buy along with the IC a thermal compound.

Check the pico fuses on the same board. Most likely you will find a blown one. These fuses look very much like a resistor, not like the usual transparent fuse, and usually yellow.

Once you have the replacement ICs, put it on the board in the same way as it was installed before. Make sure the screw holes are aligned before soldering the legs into the board.

Put a reasonable amount of thermal grease/compound between the ICs and the heat sink and fix them with the screws.

Double check the board for any splash of solders that might cause a short circuit and damage the board.

You have a problem with the main power supply regulator IC chip and the first step is to have that replaced. Does the set turn off this way when you play a DVD? Often a DVD will play fine all the way through when the reg IC is failing because the signal strength of the DVD is lower than the broadcast signal. If you replace the reg IC and the problem persists then you have to troubleshoot the High Voltage Shutdown circuit.