The bias can drift over time and caps can become leaky. Do it right, though. Don't just tweak a couple of things and call it a day. While I don't remember ever seeing one of these amps with blown outputs or anyhting more than blown fuses, it can happen.
It's definitely worth going through, though and it's a really nice amp. Purists may not like it but I really don't care. I took one to a friend for him to go though and after installing the fuses properly (cheap plastic fuse holders were in there and it was pretty ugly), I tried it and it sounded great. It still needed tweaking, though.
Components will need to be tested. Diodes, caps, transistors, etc. You might want to call Sony and ask if they have any recommendations for service shops. If you were in the MKE area, I would arrange for my friend to do it since we worked at a Sony dealer here and he was the service tech. Unfortunately, the shipping might be prohibitively expensive.
