Unfortunately there is not going to be any easy reset/fix. The Tv has an internal failure and the back panel needs to come off, checks need to be performed, then parts ordered and installed. That requires using a meter and performing complex tests on live voltages. In your case a repair shop should be consulted.
As an example of how much it will cost- Our shop charges $125 on site diagnostic fee just to hand you an estimate. Parts and labor on top of that are usually another $200-$250. This gives you an idea of whether you want to have the tv repaired or put all the money you saved into a new tv that will come with a fresh warranty, more features, better picture quality, etc.
Remember that I am here to help you. Please reply back if you need clarification on any of the above.
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