Unfortunately it will not be a fuse, we know this because the light is coming on for a second. If the fuse was bad then the light would never come on.
So that leaves us with the power supply or the main board, or possibly both. A brown out can do weird things to a television, they are very sensitive to power problems.
The really bad news is that one of these boards will need to be replaced, you will be looking at somewhere between $250-$300 for the repair. You will need to compare this to the price of a new set and determine the best route at that point.
I am sorry to bring you the bad news, but one of these boards will need to be replaced, unfortunately there is no quick fix for this problem.
If you would like any additional information or have more questions please don't hesitate to ask!
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