William Blair wrote: If you are referring to the schematics for the ASM (Add-Subtract Mechanism), they are readily available, although not including the values for the resistors which determine the logic-gate functions. A scan and my re-organised versions are accessible at: http://www.cs.ubc.ca/~hilpert/e/ABC/asm.html I was doing some calculations and experiments with vacuum tubes a couple of years ago to recreate an ASM, to figure out what might work for the logic-resistor values (not completed). It would be nice to know what the original values were. If you are referring to the schematics for the entire machine, I had the same interest when I was working on writing a simulator (also on the web pages) to confirm some aspects of the functioning of the machine. I managed to get the simulator functioning without them, so didn't feel a dire need to get them, although it would still be interesting to see them. Sometime after the sim was accessible on the web, I was contacted by one of the fellows (Charles Schorb) who had worked on the ABC reconstruction and I asked him about schematics. His reply: ... Schematics are a bit hard to come by. They requested that I return all my schematics after leaving the project for 'my real job'. Contact Gary Sleege to see if they have lightened up on this restriction. ... but I haven't pursued it further. (Actually, at universities, when school is not in session can be a good time to contact people as the people are less likely to be busy with students and teaching responsibilities, at least if they're not on vacation.)