I have one on a hard drive I don't have access to at the moment. Give me a couple days and I can put it up somewhere. I used to own the MM-20 about 20 years ago.
I am new to this forum and just purchased a Tascam System 20 with the MM-20 Mixer, PE-20 EQ, EX-20 Exender and MU-20 Meter Bridge. It came with the original schematics but no manuals were included. I am striking out elsewhere on the net but was hoping one of you had a manual for this system or know where I could find one.