I buddy of mine that repairs music gear like that has told me they are a night mare to work on because everything is soldered to single boards instead of separate, easily replaceable parts. That was done to keep costs down obviously. Maybe you could clean some of the stuff your self, and use that "potentiometer spray"? Is that stuff a good idea on this? I don't know such things. I've a Mackie 8bus and it has a bad channel or two, but I just stick red tape on those channels and don't use them. problem solved. But yeah, if it is too bad of shape, but save you time, anguish AND MONEY to just replace it
