I have the Disk1A manual on my site - and it does include schematics. Click on the "S100" header to S-100 machines, which will take you to a list of S-100 cards - the Disk1A (photo and manual) is there. Regards, Dave -- dave04a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.parse.com/~ddunfield/museum/index.html