Powering Up A Pluggable Module From The 1948 IBM 604 Electronic Calculator

June 8, 2026 by Maya Posch 4 Comments

In that awkward transition phase between electromechanical accounting systems used in the 1940s and the introduction of fully digital computers we find systems such as the IBM 604 Electronic Calculator, advertised for accounting, calculating and engineering tasks. While not capable of complex instructions, loops and other advanced features, it did use an interesting modular architecture with easily swappable modules containing a vacuum tube and associated components. Recently [Ken Shirriff] took a poke at one of these and even powered it up.

This kind of pluggable system would become a staple of computer systems, as they enabled the use of modules or cards with specific functions that could be swapped and combined at will to increase system flexibility, lower costs and make repairs a snap. For the IBM 604 a total of about 1250 vacuum tubes were used, apparently all of which were found on these pluggable modules.

The module that [Ken] got his hands on has a thyratron tube, which is effectively a high current switch and rectifier. In the short demonstration video you can see it being used to switch a lamp on and off, with further details explained in the article.

Despite being rather limited in its functionality and limited by the punch card input and output speed, the IBM 604 was still a smashing commercial success with over 5600 units produced. A transistorized prototype version with 2200 transistors and 95% less power usage was created in 1954 that formed the basis for the IBM 608, the world’s first commercial all-transistorized calculator.

The 608 didn’t last too long, however, as at that point the breakneck pace of semiconductor technology meant that any newly released product was already obsolete by the time it hit the market. Despite this, fundamentals like pluggable modules would keep showing up over and over, ranging from the 1950s Bendix G-15 to even modern day systems, including PCs with pluggable RAM and expansion cards as well as mainframes where hot swapping of even entire CPU modules is just another feature.

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A New Life For A Rare Console

June 7, 2026 by Jenny List 6 Comments

One of the delights of our tips line is that from time to time it brings us retrocomputing hardware that, despite years of reporting, we were not aware existed. [Hitmanmcc] has just such a machine, an NEC PC Engine LT. It’s a PC engine in a laptop form factor, and like many of this super-rare console, it has succumbed to capacitor failure. We’re treated to the process of bringing it back to life.

Replacing capacitors was only part of the story for this repair, as the electrolyte had caused damage elsewhere on the board. In particular there is a small transformer that forms part of an inverter to generate an LCD bias voltage, and this had been destroyed. Fortunately the art of switching power conversion has advanced in the decades since the console was produced, and a small module was procured to do the same job.

The result of all this surgery is another rare console rescued from e-waste, and an opportunity for the rest of us to take a look too. The PC engine is a relative rarity here, but we’ve had a few hacks over the years. This converter for its American cousin is one.

An Unlikely Host For An 8080 Emulator

June 6, 2026 by Jenny List 10 Comments

To emulate vintage microprocessor hardware, it’s normal to find a modern host that provides alongside the number-crunching grunt, sufficient physical connections to interface with its support hardware. Thus if you were shopping around it might be reasonable to pick something with a powerful core and plenty of pins. Yet to emulate an 8080, [Ted Fried] has eschewed both of these — opting for an ATtiny85, a microcontroller deficient in both pins and processing power.

This seemingly impossible feat is achieved by reducing the physical connection to an SPI bus and offloading the support functions to a Teensy. The emulation code is significantly optimized C, and includes a 128 byte cache to speed up matters. This delivers a speed claimed to be only very slightly slower than a real 8080 when booting CP/M, which is quite a feat.

We’re sure that CP/M enthusiasts will have fun with this project, and we especially like the full write-up. Going to the effort of making fake 1975 electronics magazine covers for the project really is going the extra mile, and we appreciate that. Meanwhile if you’d like one of your own, the whole thing can be found in a GitHub project.

If you’re not familiar with the 8080, maybe we can get you started.

Using Windows 11 On An LGA 775 PC With AGP Videocard

June 5, 2026 by Maya Posch 15 Comments

Although the thought of installing a modern operating system like Windows 11 on something as archaic as a Core 2 Quad Q6600 Intel CPU may seem ridiculous, it being the flagship CPU of the time means that it still chews up low-end Celeron systems that are on the supported hardware list like the N4020. Hence [Omores] commencing on this latest adventure, with the snag being that the chosen mainboard features an AGP bus that Windows 11 no longer supports.

A GPU box from the related HD 4670 PCIe card, not the used HD 4650 AGP card with 1 GB of DDR2. (Credit: Omores, YouTube) — A GPU box from the related HD 4670 PCIe card, not the used HD 4650 AGP card with 1 GB of DDR2.

This system is intended to multi-boot a range of Windows OSes starting with Windows 98, while also playing nice with DOS and even Windows 11. In addition to the quad-core, 2.4 GHz Q6600 there’s also an amazing 3 GB of DDR1 RAM in the system.

The mainboard is the 2003-era Asrock 865PE, with the GPU being the highest-end GPU that still came in AGP flavor: the Radeon HD 4650 from 2009. Since the sole reason that Windows 11 doesn’t support AGP any more is due to the supporting files not being included with Windows 11, hence you can track it down on a Windows 10 1507 release install – such as the Intel AGP440.sys driver here – and install them with some file editing.

Since Windows 11 still supports the WDDM driver model from Windows Vista and 7 you can then install the Catalyst drivers from 2012 and be up and running. You only get 1 GB of VRAM for this card, but you probably don’t need much more on this level of hardware.

One major stumbling block remains, however, as Windows 11 24H2 enforces SSE4.2 instructions which the CPU doesn’t support. Ergo 23H2 is the newest Windows 11 version that can run on this system, with only the Education and Enterprise still receiving security updates, making it a bit of a pyrrhic victory, especially as Windows 7 benchmarks a fair bit faster on the same hardware.

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The World’s First GPIB Speech Synthesizer, And It’s For A GRiD Compass

June 4, 2026 by Jenny List 2 Comments

The GRiD Compass is a legendary portable computer — a taste of an early-80s future with bubble memory, tough enough for NASA to take them into space, and one of the machines which defined the beginnings of the form factor we know today as a laptop. They’re not easy to come by, but [Scott M. Baker] got his hands on one. As well as nursing it back to health, he’s made an unusual peripheral, a GPIB speech synthesizer.

The GRiD arrived in one piece despite sketchy packaging, and after a little confusion over its line voltage it ran as well as the day it was made. It was designed to use GPIB as its interface for large peripherals such as printers or disk drives, so it was that interface picked for the speech synthesizer. It emulates a GPIB printer, and bytes are sent to the synthesizer chip by printing to LPT1, making driving it an easy process.

The synth itself is a clever design that allows the use of all the various speech chips of the day. It achieves this using a GPIB carrier board holding the interfacing, and a set of plug-in modules, one for each different chip. It’s certainly an unusual peripheral.

You can see more details in the video below the break, meanwhile if you can’t get the real thing there’s a cyberdeck tribute you can make.

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Restoring Apple’s Terrible But Awesome IBook Laptop

June 1, 2026 by Maya Posch 17 Comments

Before the Apple MacBook there was the Apple iBook, fruity 1999 colors included. These PowerPC-based laptops targeted low-cost PC-compatible laptops much like the iMac did, albeit it the latter with more success. That said, these laptops are said to be a nightmare to repair, so when [This Does Not Compute] got his hands on a shiny first generation, 300 MHz PowerPC powered, tangerine-colored one, he somewhat dreaded trying to fix it.

Aside from some relatively minor cosmetic issues such as typical cracks in the plastic and a missing optical drive door it seemed in good condition. The first issue came on boot, when MacOS 9.0 would throw up an error message about an issue with cache memory. After booting into the OS this cache memory did indeed show up as missing. Next issue was the optical drive doing absolutely nothing and restarting leading to the system locking up and not starting until plugging in the power adapter.

Fortunately the optical drive started working after addressing a software issue, but the power and cache issues were concerning. Cue a long troubleshooting and repair session that involved purchasing a ‘parts unit’ from Japan to merge both into a single iBook with hopefully a working system at the end.

Along the way the reason why people dislike maintaining these systems, as to do something like getting to the hard drive requires removing the entire display. The cause for the first iBook’s problems also seemed to be due to a liquid spill of some type, as on boot there was no chime either, indicating a wider board-level issue. Unfortunately this was left further undiagnosed and the Japanese mainboard used instead. It’d be interesting to see the deeper cause, but most likely the mainboard will be used for components.

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A Camera Viewfinder Makes A Great TV

May 31, 2026 by Jenny List 2 Comments

When we think of CRT camera viewfinders, most of us probably imagine the tiny CRTs you’d find in a 1980s camcorder. They’re super cute and a load of fun to play with, but they’re very much a consumer device. Professional cameras of the type you’d find in a studio had their own viewfinders, which were a lot closer to a small TV. They’re about as high quality as it gets for a monochrome CRT, and [Evan Monsma] has done the conversion to a general-purpose monitor.

On one side, this is a very straightforward hack, simply a case of tracing wires to identify the power and video pins. Given a tool battery, the monitor fires up and gives a super-sharp picture. What we like about this is the wooden base he’s made for the thing, at the same time rough-and-ready, and professional-looking from the outside. It has a routed space for the cables, and once mounted flush with the monitor base and given a bit of wood stain, it looks almost as though it was manufactured that way.

It’s likely most of us won’t find a broadcast viewfinder in the trash, instead settling at best for a little Chinese portable TV. But it’s still interesting to see these unusual devices. Perhaps it might make a good cyberdeck.

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