If its a MkII then the bits you are interested in are the same as the KV-1310UB and KV-1330UB. I've written loads on this forum about how to deal with these, it is not easy!
You'll probably find that some or all of these transistors have failed:
Chopper, Line Output, Converter, EW Output, Frame Output (x2).
They are all Sony specials and difficult to substitute. There will be a reason why they have failed too, it you don't find it you will be back to where you started as soon as you switch on. This isn't a set for the beginner or the capacitor monkey, it needs careful thinking about and a logical, step by step approach.
Read this first:
https://www.vintage-radio.net/forum/...d.php?t=151193
and this:
https://www.vintage-radio.net/forum/...d.php?p=917920
(scroll back up to the top)
If it were me I'd test the tube first. If it is good, put it in one of the many still-working examples and save a lot of time and grief. If it isn't, you are wasting your time anyway, the set is only good for parts (excluding whatever has already failed of course).