Yamaha A700 repair attempt


I just got ahold of a very dead Yamaha A700 amplifier. It has at least one blown channel, with super serious damage. Tons of blown semiconductors and literally burned resistors.

However, I am trying to determine if the other channel works. Nothing burned and all the semis I've tested appear OK.

I haven't dared to start this thing up with a dim bulb tester, but with it, I get +42VDC before the relay contacts, on the "good" channel. I don't quite understand why.

I've tried to remove the dead channel's influence, but without much success. I have removed the B+ and B- connections to it, as well as the output transistors and drivers, and a couple other misc transistors.

That channel still has +37VDC on the speaker output (before relay contacts). I don't understand why this is.

The schematic looks like this: http://i.imgur.com/p85GPwJ.jpg

I feel lost. Got any ideas for me?