Michael Gardi built a nice replica of the Minivac 601 computer kit, and made the plans available on Instructables.
Created by information theory pioneer Claude Shannon as an educational toy for teaching digital circuits, the Minivac 601 Digital Computer Kit was billed as an electromechanical digital computer system. Produced by Scientific Development Corporation in the early 1960s it sold for $85 (about $720 today).
Minivac 601 used electromechanical relays as logic switches as well as for very basic storage. Simple DPDT switches and SPDT push buttons made up the binary inputs, with lights to represent the outputs. A large motorized dial allowed the user to enter decimal or hexadecimal numbers, and to output numbers, or to act as a clock signal generator. For more information about the Minivac 601 here are some additional references:
The Instructable presented here is for a full size replica of that Minivac 601 from 1961. I have tried to remain as true to the original as possible given the technologies and resources available to me. I don't have a "vintage" unit so this replica has been constructed based on photos and from the original manuals that were available online. I have included these manuals in PDF format as part of this project. I brought these files to a local copy center and had them printed as the spiral bound booklets you can see [below]. I'm really happy with the results.