1.) Ok, you have found your problem---3 blinks is short protection--usually means in this set that one of the two STK-392-110 convergence chips is bad.
2.) I have detailed step by step and start to finish instructions for this repair in this set--I can email them to you if you think you can do the repair yourself. The instructions tell you what things you will need to do it.
3.) If you are not able to do it shop around as most shops TRY to charge 300-400 for this repair. You can buy the pair of chips on Ebay for less than 13 dollars plus shipping.
4.) There is a simple reason this problem happens--the chips are about 2 1/2 inches wide and 1 1/2 inches tall on heat sinks with fins and side by side--they are black and the STK-392-110 number will be printed on them in white---the back of each chip is metal and a white grease is applied to them when they are bolted to the heat sink--after 5 years or longer from the heat the grease dries out and one of the chips cannot move the heat fast enough to stay cool (the grease makes the transfer of heat quick).
5.) There are some blue resistors in front of the chips that are marked 2.2 ohm---if you look and any are white in the middle--they are gone and need to be replaced also(cheap part 2.2 ohm 1 watt resistor) it is a good idea to check all of them.
6.) If you are not able to do the repair shop around in your area--if they say "it has to go to the shop" keep looking---any good tech can do this repair in your home in about a hour--I do hundreds of them here in home for 200-250 total.
7.) If you want the instructions just give me a vote here ( I will email them to you) as I do this here for free.
If you have questions reply to this posting here as I am here to help people[email protected]