For sale are new-made reproductions of the Ohio Scientific 400 "Superboard" 6502 CPU board. These boards were produced from 4000 DPI scans of an original Ohio Scientific 400 board and are 1:1 with respect to trace and hole placement. They were run on standard thickness FR4 stock, which is thicker than original OSI stock, to reduce the excessive flex experienced with original Ohio Scientific products.

These boards have been scanned and reproduced as part of the Ohio Scientific Preservation Project. Full documentation is available in PDF format online. Unfortunately, due to 's external links policy, we can no longer link directly to PDF documentation or the OSI Preservation Project website.

The OSI 400 "Superboard" was Ohio Scientific's step-up offering from the OSI 300 and provided the basis for a more expandable system. The OSI 400 is a single-board computer, supporting 1K of static RAM and 512 bytes of ROM (2x 1702As), along with a 6850 ACIA for the console serial port. It also provides OSI 48-pin bus compatibility and an uncommitted 40-pin DIP prototyping area that can be used for a 6820 PIA, 6530 RRIOT, more RAM/ROM, etc.

While the OSI 400 board is usually seen with a 6502 CPU, it also supports the Motorola 6800 CPU and MOS 6501 CPU (MOS's first product, which due to a lawsuit from Motorola was never produced in large quantities).