I can only guess you wanted it to be covered but that's me guessing. I don't see any TV maker with more than 2 years warranty so with that out of the way, why not change that board?
I see shopjimmy and other sites sell such things.
I have a Sony plasma model FWD-50px2 which was Having colored vertical lines on picture. I was ok with that until 4 days ago I got a clicking sound when I turned on tv. It goes green for couples seconds with this weird clicking sound and just shuts off. Had a tech look at it and confirmed it was a power supply board.
Called Sony and they pretty much told to F- off. There something they can do? They should support there product which I only had for 4 yrs and dropped over 2k for it.