I have a C1P and i discovered someone else at work used to work with them extensively. He might have some parts. I think I might have some disk controller boards, but all my schematics and printed material is out on loan right now. david In a message dated 98-01-15 12:59:46 EST, you write: << I have several Ohio Scientific Challenger ][ machines but none of them are disk based. I'd be willing to trade some of them in exchange toward getting a disk based system up and running. I don't have the inventory off the top of my head but I can sure figure out what I have and see if we have any trading possibilities. George >>