I don't know where you can get a manual, but if you have any specific questions, I might be able to help. I started on that machine way back when. I may be able to remember some things about it.
I've figured a lot of it out, except for the two switches in the center that have three positions each. They are labled with RECORD FUNCTION, then each switch is named BUSS L and BUSS R. The BUSS L switch has positions labled 1, SAFE, and 3. The BUSS R switch has positions labled 2, SAFE and 4. What does all this mean? Also a quick tutorial of all of it would be nice.