Restoring An Unusual Piece Of Computing History

September 6, 2020 by Tom Nardi 46 Comments

Trawling classified ads or sites like Craigslist for interesting hardware is a pastime enjoyed by many a hacker. At a minimum, you can find good deals on used tools and equipment. But if you’re very lucky, you might just stumble upon something really special.

Which is exactly how [John] came into possession of the TRANSBINIAC. Included in a collection of gear that may have once belonged to a silent key, the device is a custom-built solid-state computer that appears to have been assembled in the early 1960s. Featuring a large see-through window not unlike what you might find on a modern gaming computer and a kickstand that tilts it back at a roughly 45° angle, it was obviously built to be shown off. Perhaps it was a teaching aid or even a science fair entry.

After some digging, it looks like the design of the TRANSBINIAC was based on plans published in the January 1960 issue of Electronics Illustrated. Though there are some significant differences. This computer uses eight bistable flip-flip modules instead of the original six, deletes the multiplication circuit, and employs somewhat simplified wiring. Whoever built this machine clearly knew what they were doing, which for the time, is really saying something. This truly unique machine may well have been one of the first privately owned digital computers in the world.

Which is why we’re glad to see [John] trying to restore the device to its former glory. Naturally it’s a little tricky since the computer came with no documentation and its design doesn’t exactly match anything out there. But with the help of other Hackaday.io users, he’s hoping to get everything figured out. It sounds like the first step is to try and diagnose the 2N554 germanium transistor flip-flop modules, as they appear to be behaving erratically. If you have experience with this sort of hardware, feel free to chime in.

We’re supremely proud of the fact that so many of these early computer examples (and the people that are fascinated by them) have recently found their way to Hackaday.io. They’re literally the building blocks on which so much of our modern technology is based on, and the knowledge of how they were designed and operated deserves to live on for future generations to learn from. If it wasn’t for 1960s machines like the TRANSBINIAC or the so-called “Paperclip Computer”, Hackaday might not even exist. It seems like the least we can do is return the favor and make sure they aren’t forgotten.

[Thanks to Yann for the tip.]

Transistor Logic Clock Gets Stacked Up

September 6, 2018 by Tom Nardi 9 Comments

A couple years back we covered a very impressive transistor logic clock which was laid out so an observer could watch all of the counters doing their thing, complete with gratuitous blinkenlights. It had 777 transistors on 41 perfboards, and exactly zero crystals: the clock signal was extracted from the mains frequency of 50 Hz. It was obviously a labor of love and certainly looked impressive, but it wasn’t exactly the most practical timepiece we’d ever seen.

Creator [B Brett] recently wrote in to share news that the second version of his transistor logic clock has been completed, and we can confidently say it’s a triumph. He’s dropped the 41 perfboards in favor of 9 professionally fabricated PCBs, which this time around are stacked vertically to make it a bit more desktop friendly. The end goal of a transistor logic clock that you can take apart to study is the same, but this “MkII” as he calls it is a far more refined version of the concept.

In addition to using fewer boards, the new MkII design cuts the logic down to only 283 transistors. This is thanks in part to the fact that he allowed himself the luxury of including an oscillator this time. The clock uses a standard watch crystal at 32.768 KHz, the output of which is converted into a square wave through a Schmitt trigger. This is then fed into a divider higher up the stack which uses flip flops to produce 1Hz and 2Hz signals for use throughout the rest of the clock.

In addition to the original version of this project, we’ve also seen a beautiful single-board wall mounted version, and even a “dead bug” style one built from scraps.

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Transistor Logic Clock Has 777 Transistors

June 1, 2016 by Moritz Walter 23 Comments

Sometimes, the parts list says it all. 777 transistors, 1223 resistors, 136 LEDs, 455 crimp connectors, 41 protoboards and 500 grams of solder. That’s what went into this transistor logic clock build.

While additional diodes and capacitors were tolerated in this project, a consequent implementation of a discrete transistor logic clock, of course, does not contain a quarz oscillator. Instead, it extracts its clock signal from the mains frequency in its power supply. Because mains frequency is slow, it can be stepped down to a clock-applicable 1 Hz by a simple counter unit which already spreads its discrete transistors across 4 protoboards.

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