Authentic 1976 TB-1 Extender Card for microcomputers S-100 bus. Practically ancient computer technology, for hobbyists testing built systems like the MITS ALTAIR or IMSAI 8080.

Made by Bob Mullin and the original markings are still fully intact on the card. These are very rare to find and now’s your chance to get one, cannot find any other available. Made back in the days before the personal computer, where they instead were called microcomputers and came in kits, this was a device used to test those computers ensuring they are properly functioning and helping to find the root issue if there is one. No idea as to the functionality of this board.

Would make a cool piece for someone in the tech industry or interested in electronics and/or technology. Whether a back board to something else or part of some sort of art project I think this thing could be really cool, though also quite a unique and rare piece of history that some may want to preserve. There are many uses this might have.

Condition: It is a blank board. The 100-pin edge connector has zero cracks and the gold plated fingers at the bottom are still all in great condition. Please see photos for the best description and understanding of its condition as the item photographed is the exact item you can expect to receive.

If you have any questions, need any information, would like additional photos, or anything else please message me.

3 ways this device was used in test microcomputers include but aren’t limited to:

• Signals and Voltages: Technicians used its built-in logic probe or external equipment to check clock rates, data and address bus integrity, and voltage drops.

• Logic States: It allowed engineers to isolate and track logic high/low states to see where a malfunctioning board was failing.

• Troubleshooting: Users could safely attach clips and probes to individual integrated circuit pins without risking accidental shorts against adjacent densely packed boards.