I have done alot of googling on this amp head and I found out alot, but I still can't find some stuff.

I'm trying to find the schematic and user manual for it. I found on yamaha's website the manual for the III but no info for the II.

I picked it up a few yrs back and most of it works. I picked it up cheap because the B channel does not work at all. I had used a pedal with it but since PCSed a few yrs ago I haven't even played it.

The clean channel sounds great. But I decided maybe it's time to try figure out what's wrong with the B channel.

While I'm not an electronics guru, I did go to college for HVAC so I am familiar with wiring diagrams and working on things. I also build guns and cars and do everything from welding and machining to finish work. I have also been into car audio since before I could drive and built my own crossovers. Basically I like working with my hands and don't mind getting dirty and I think I can handle this project.

Does anyone have a source for a schematic? and/or any tips on troubleshooting this beauty? I'm hoping it's a simple fix like the A/B switch but I need to start tearing into it.

thanks for any help
Leon