Presumably you aren't in Europe? (as I don't recognise the model number), but as far as I know there are no circuits for any Sony TV's any more, and haven't been circuits for their PSU's pretty well since flat screen sets first appeared. I used to be Chief Engineer for a Sony Service Dealer, and did all their Sony Warranty repairs.
Service procedure (in or out of warranty) is to replace entire PCB's (whilst available) - once out of warranty you can sometimes work out what's wrong, and replace individual parts, but it's difficult with no circuits and no manufacturers spares.
Are you 100% the PSU is faulty?, they were generally EXTREMELY reliable (at least in Europe) as Sony specify higher quality parts than others do.