Samsung Y-board PS42C91

[blownelco]

Hello,

I have a samsung PS42C91 ( F31A calla). with the following problem,
Y board is shorted, i replaced two IGBT onto the Y-board.
After that the set works again, but after a week or two the set doesn't turn on at first try.

then it is broken again.
Does anyone have an idee what is the problem?

please help