Retrocomputing

1587 Articles

Sol-20 Integrated Computer Teardown

February 14, 2023 by 19 Comments

[Action Retro] came into an antique Sol-20 computer and argues that it was the first totally integrated computer aimed at consumers that didn’t require you to buy or build some kind of terminal. These are fairly rare, so we appreciated the peek inside that you can see in the video below.

Sure, the Sol-20 wasn’t the very first computer out there in the market. It was, however, one of the first ones that didn’t need anything more exotic than a monitor to have a functional system (and the monitor was included). There were alternatives such as a Xerox Alto or a Wang 2200, but those had price tags that didn’t land them in your home. Even Apple, which would become famous for a turnkey system, was only producing the Apple I at that time. As the video points out, it was complete as long as you could build your own power supply and knew how to interface a keyboard — keeping in mind that keyboards were all wildly different in those days.

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Too Cool For 8-bit Retro? Try 1-bit Gaming

February 14, 2023 by 5 Comments

While the world has been racing for higher and higher bit counts for CPUs, there are always those that buck the trend. Consider the venerable Motorola MC14500B, a 1-bit CPU, no kidding. [Usagi Electric] built up a computer based on one of these chips using a breadboard but has since pulled it apart to use the breadboard for other things. So this time, he’s made a permanent version on a PCB and created a simple game to show it off. You can see the result in the video below.

Well, the chip had one bit in the datapath. It did not have any memory, but it did have a way to feed it 4-bit instructions, and, as you might guess, there were 16 possibilities for instructions. The chip was meant to replace industrial controllers where even a PLC might be overkill, and apparently, it did see some use in the real world.

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RCA’s Clear Plastic TV Wowed Crowds In 1939

February 12, 2023 by 25 Comments

In the United States in 1939, television sets still had a long way to go before they pretty much sold themselves. Efforts to do just that are what led to RCA’s Lucite Phantom Telereceiver, which aimed to show people a new way to receive broadcast media.

Created for the 1939 World’s Fair, the TRK-12 Lucite Phantom Telereceiver introduced people to the concept of television. Production models were housed in contemporary wood cabinets, but the clear acrylic (itself also a relatively new thing) units allowed curious potential customers to gaze within, and see what was inside these devices.

One interesting feature is the vertically-mounted cathode ray tube, which reflects off a mirror in the top cover of the cabinet for viewing. This meant that much of the bulk of the TRK-12 could be vertical instead of horizontal. Important, because the TRK-12 was just over a meter tall and weighed 91 kilograms (or just over 200 lbs.)

Clearly a luxury item, the TRK-12 sold for $600 which was an eye-watering sum for the time. But it was a glimpse of the future, and as usual, the future is made available a few ticks early to those who can afford the cost.

Want to see one in person? You might be in luck, because an original resides at the MZTV Museum of Television in Toronto, Canada.

Dungeons And Dragons Board Game From The 1980s Holds A TMS1100

February 12, 2023 by 10 Comments

Today is a little tour back to the early 1980s when Mattel released the DUNGEONS & DRAGONS Computer Labyrinth Game. [Cameron Kaiser] was dealing with a few boxes of old stuff when he came across the game. Luckily for us, he decided to do a complete teardown and a comprehensive review more than 40 years after it came out.

The game itself is pretty simple. You and a friend are characters on the board, navigating an eight-by-eight maze. As you move through the labyrinth, a microcontroller emits twelve audio cues telling you what you’ve run into (walls, doors, treasure, and so on). The eight buttons on the side allow you to hear the different tones to know what they mean, as we imagine even the most well-written manual might struggle to describe that. In addition, the pieces are diecast metal, which allows the game to detect where the pieces have been placed. Continue reading “Dungeons And Dragons Board Game From The 1980s Holds A TMS1100” →

Connecting A Keyboard To A Vintage PC-XT, The Hard Way

February 7, 2023 by 16 Comments

We’re not sure if there’s any single characteristic that qualifies someone as a hacker. After all, we’re a pretty eclectic bunch, with skills that range all over the map, and what one person feels is trivial, others would look upon as black magic. But there’s one thing we’re sure of: if you find yourself reading the original POST code for the PC-XT motherboard just to get a keyboard working, you’re pretty much our kind of people.

That was the position [Anders Nielsen] found himself in as work progresses on his “PC-XT from Scratch” project, which seeks to build a working mid-80s vintage IBM Model 5160 using as many period-correct parts as possible. The first installment of the series featured the delicate process of bringing the motherboard up, lest the magic smoke was released. After seeing some life out of the old board, [Anders] needed a little IO, specifically video and keyboard. The video side of the equation was relatively trivial, with an early-90s VGA card from eBay — not exactly period correct, but good enough to get something to display. Continue reading “Connecting A Keyboard To A Vintage PC-XT, The Hard Way” →

Reliving A Bitmapped Past With A Veritable Hoard Of Bitmap Fonts

February 4, 2023 by 12 Comments

The fonts seen with old computer systems such as those from Apple and Commodore, as well as Microsoft Windows 3.1 and older, form an integral part of our interaction with these systems. These days such bitmap fonts are a rarity, with scalable vector-based fonts having taken their place on modern-day systems. This unfortunately also means that these fonts are at major risk of being lost to the sands of time. This is where [Rob Hagemans] seeks to maintain an archive of such bitmap fonts, ranging from Acorn to MSX to Windows.

Many of these fonts are extracted from character ROMs, with a preview of some of these fonts available via the Monobit viewer. The fonts themselves are made available in YAFF format, which is a text-based format that can be converted back to a binary format using the Monobit tool. If you ever wanted to use one of these old bitmap fonts in a project, this would seem to offer a treasure trove of options. The hoard of bitmap fonts might be the perfect fit for your next graphic LCD project.

(Via [SuperIlu] on Mastodon)

A visually accurate replica of the MCM/70 computer, an all in one system with a keyboard, dual cassette drives and a small one line display

MCM/70 Replica Embodies Proud Canadian Heritage

February 4, 2023 by 17 Comments

When a vintage computer is all but unobtanium, software emulation is often all that remains. Unless you are [Michael Gardi], who saw an opportunity to reproduce Canada’s home-grown MCM/70 microcomputer using a combination of software emulation and modern hardware.

Short of building a brand new MCM/70 from the original schematics, this faithful facsimile of the MCM/70 does everything it can to pay homage to the original machine. The foundations of this project can be attributed to the York University Computer Museum (YUCoM) MCM/70E emulator, highly regarded for its “historical accuracy”. The MCM/70 used dual cassette tapes for storage and a funky 32-character dot matrix plasma display, which is all reproduced in software (other versions dropped one of the cassette drives for a modem, bleeding edge innovation for 1974 microcomputing).

From here, [Michael] set off to assemble the various physical components of the original computer. The chassis itself was built from scratch using a mixture of 3D printing and traditional woodwork. The high-voltage plasma display was recreated using four HCMS-2972 dot matrix modules, which minor compromises. The original computer used display memory as extra storage when executing instructions, which created a sporadic blinkenlights effect on the original display. This new display unfortunately won’t reproduce this ‘thinking’ pattern, but it’s a small sacrifice.

Similarly, the original keyboard was going to be challenging to replicate with 100% accuracy, so a brand-new recreation of an Ohio Scientific computer keyboard was used instead. The layouts are extremely similar, and anyone except your most committed Canadian retro computing enthusiasts probably wouldn’t notice the difference. Being a modern recreation of a vintage keyboard, this was relatively easy to source. A set of custom-made keycaps with APL legends really helped sell the replica.

And while working dual cassette drives would have brought this project home, it’s commendable that [Michael] has created ‘working’ cassette drives using 3D printed cassettes and some magnetic magic using hall effect sensors to identify the loaded cassette. The emulator incorporates three virtual cassette tapes which made this solution possible.

If this all sounds familiar, it might be because this project was based on a superb Hackaday writeup of the MCM/70. A truly innovative computer for its time, the story behind Micro Computer Machines (not to be confused with the toy cars) is a fascinating tale, and the write-up is worth a read if you haven’t seen it already.

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