Welcome to The Ersatz Planet Oberheim Databank
I've owned a few Oberheim synthesizers in my life and have collected schematics and designed metalwork chassis for them. These are the links to them. Many thanks to the people on the net whom I snagged the schematics I didn.t have. I have converted these all to Adobe Acrobat PDF files.
The Oberheim Synthesizer Expander Module (SEM)
The Schematics for the Synthesizer Expander Module (SEM)
The Oberheim 2-voice
The Oberheim 4-voice