You know the company is still in business and will most likely have what you need. So you purchased these without any supplied schematics? That wasn't very nice of them. I hate when that happens.

It's fun to trace out circuit boards. No big whoop.
Mx. Remy Ann David

Hi! Thanks for your reply.. Yes, I called the company but they seem to have lost all of the documentation from their 70s products. I tried to contact people who worked there, but no one have info on gear dated that long ago. I can't find any studio who have the same desk either... This desk seems to be quite unique.