Somebody might have an idea

[dr.ido]

It could be a heat related fault (dry joint, etc). That would explain how it ran for a while before shutting down, but wouldn't start up again. Will it start up again if it is left to cool down completely?

If the horizontal driver transformer is dry jointed (a common fault in some Sony's, but I've yet to work on any of the WEGA series) it could have taken out the horizontal output transformer.

[Earlsays]

is the horizontal output transformer an expensive fix? I was reading that a problem on some of the WEGA tvs is that they have a transformer mounted on a board which cannot support the weight of the transformer sitting on the board, and the board cracks...600 doller repair in that case, which, isn't worth it...I'll probably just dump it back where I found it....well maybe...I hate to do that though...these throwaway electronics are truely sad...

[RetroHacker]

Just check for cold solder joints or board cracks. Even if the board is cracked and broken, it can still be repaired. Some glue will hold the board back together, then you can bridge across the cracks with bits of wire and solder. A support under the board will prevent it from breaking again.

I've not worked on a WEGA, so I don't know anything about it. But check for cold solder joints. They seem to plauge modern TV's. I think it was somewhere in the 80's where many TV manufaturers entirely forgot how to solder. Sony seemed to have it down until the mid 90's, then promplty forgot.

-Ian