The Data620 computer is a unique machine built entirely with analog electronic circuitry. It uses a VersaLOGIC signaling scheme, where a logical 0 is represented by 0 V, and a logical 1 is represented by -12 V. This unconventional voltage scheme distinguishes it from modern digital systems and makes troubleshooting its boards particularly challenging.
The Data620 is constructed from standard electronic components—resistors, capacitors, diodes, and transistors—across a large number of printed circuit boards (PCBs). Some of these boards may include faulty components, and currently, there is no dedicated testing device to verify their functionality.
This project aims to develop such a testing device, enabling systematic diagnostics and repair of Data620 PCBs.
The conceptual design of the VersaLOGIC board tester is now complete, simulated, and validated through multiple proofs of concept. All the heavy lifting on the theoretical side is done.
A more detailed status report can be found on the status page.
The remaining work primarily focuses on:
- PCB design – to enable practical testing of Data620 boards.
- Software development – implementing the testing logic for the board tester.
In short, the foundation is solid, and we are now entering the “making it real” phase.
- Hardware: Preliminary designs and SPICE simulations are complete, showing that the concept is viable.
- Software: Development will proceed now that a stable hardware design exists.
- Independence: This project is an independent effort, not affiliated with Usagi Electric or other existing Data620 projects. That said, collaboration opportunities are welcome.
As this project is still evolving, constructive feedback and suggestions from the community are highly appreciated.
For more context about the Data620 computer:
- Retrocomputing Forum: Data-620 Transistor Minicomputer
- GitHub: Nakazoto/Data620
- YouTube: Data620 Overview
We thank Usagi Electric and the community for their ongoing dedication to preserving this remarkable piece of computing history.