IBM Selectric Typewriters Finally Get DIY Typeballs

April 11, 2023 by Bryan Cockfield 29 Comments

IBM’s Selectric line of typewriters were quite popular in the 1960s, thanks in part to an innovation called the typeball which allowed for easy font changes on a single machine. Unfortunately, as if often the case when specialized components are involved, it’s an idea that hasn’t aged particularly well. The Selectric typewriters are now around 60 years old and since IBM isn’t making replacement parts, those restoring these machines have had to get somewhat creative like using a 3D printer to build new typeballs.

It sounds like it would be a simple, but much like the frustration caused with modern printers, interfacing automated computer systems with real-world objects like paper and ink is not often as straightforward as we would like. The main problem is getting sharp edges on the printed characters which is easy enough with metal but takes some more finesse with a printed plastic surface. For the print, each character is modelled in OpenSCAD and then an automated process generates the 3D support structure that connects the character to the typeball.

This process was easier for certain characters but got more complicated for characters with interior sections or which had a lot of sharp angles and corners. Testing the new part shows promise, although the plastic components will likely not last as long as their metal counterparts. Still, it’s better than nothing.

Regular Hackaday readers may recall that the ability to 3D print replacement Selectric typeballs has been on the community’s mind for years. When we last covered the concept in 2020 we reasoned that producing them on resin printers might be a viable option, and in the end, that does indeed seem to have been the missing element. In fact, this design is based on that same one we covered previously — it’s just taken this long for desktop resin 3D printing technology to mature enough.

How To Restore A Musical Amiga

December 24, 2022 by Bryan Cockfield 21 Comments

Despite the huge strides in computing power and functionality that have been achieved in the past few decades, there are still some things that older computers can do which are basically impossible on modern machines. This doesn’t just include the ability to use older hardware that’s now obsolete, either, although that is certainly a perk. In this two-part restoration of an Amiga 500, [Jeremy] shows us some of these features like the ability to directly modify the audio capabilities of this retro machine.

The restoration starts by fixing some damage and cleaning up the rest of the machine so it could be powered up for the first time in 30 years. Since it was in fairly good shape he then started on the fun part, which was working with this computer’s audio capabilities. It includes a number of amplifiers and filters in hardware that can be switched on or off, so he rebuilt these with new op-amps and added some new controls so that while he is using his MIDI software he can easily change how it sounds. He also restored the floppy disk drives and cleaned up the yellowing on the plastic parts to improve the overall appearance, as well as some other general improvements.

These old Amigas have a lot going for them, but since [Jeremy] is a musician he mostly focused on bringing back some of the musical functionality of his childhood computer, although he did build up a lot of extra features in this machine as well. These types of audio circuits are not something found in modern computers, though, so to get a similar sound without using original hardware you’ll need to build something like this NES audio processing unit programmed in Verilog.

Continue reading “How To Restore A Musical Amiga” →

Closeup of a film restorer's hand holding a 35mm film print to check for defects as it goes into a film scanner

35mm Film Restoration Process Explained

December 19, 2022 by Dave Walker 9 Comments

For a large part of the 20th century, motion pictures were distributed on nitrate film. Although cheaper for the studios, this film was highly flammable and prone to decay. On top of that, most film prints were simply discarded once they had been through their run at the cinema, so a lot of film history has been lost.

Sometimes, the rolls of projected film would be kept by the projectionist and eventually found by a collector. If the film was too badly damaged to project again, it might still get tossed. Pushing against this tide of decay and destruction are small groups of experts who scan and restore these films for the digital age.

still showing the difference in quality between a 16mm print of a 35mm animated movie and a new scan of the 35mm original — The quality difference between a smaller-format print and the original restored negative can be startling

The process is quite involved – starting with checking every single frame of film by hand and repairing any damaged perforations or splices that could come apart in the scanner. Each frame is then automatically scanned at up to 10K resolution to future-proof the process before being painstakingly digitally cleaned.

The real expertise is in knowing what is damage or dirt, and what is the character of the original film. Especially in stop-motion movies, the subtle changes between frames are really part of the original, so the automatic clean-up tools need to be selectively reined in so as not to lose the charm and art of the film-makers.

The results are quite astonishing and we all have teams like this to thank for protecting our cultural heritage.

If you’re interested in watching the process, then check out the video after the break. If you fancy a go at automatic film digitising yourself (preferably not on unique historical prints!) then we’ve shown projects to do just that in the past.

Thanks to [Cliff Claven] for the tip.

Continue reading “35mm Film Restoration Process Explained” →

Hackaday Links: November 13, 2022

November 13, 2022 by Dan Maloney 6 Comments

Talk about playing on hard mode! The news this week was rife with stories about Palmer Luckey’s murder-modified VR headset, which ostensibly kills the wearer if their character dies in-game. The headset appears to have three shaped charges in the visor pointing right at the wearer’s frontal lobe, and would certainly do a dandy job of executing someone. In a blog post that we suspect was written with tongue planted firmly in cheek, Luckey, the co-founder of Oculus, describes that the interface from the helmet to the game is via optical sensors that watch the proceeding on the screen, and fire when a certain frequency of flashing red light is detected. He’s also talking about ways to prevent the removal of the headset once donned, in case someone wants to tickle the dragon’s tail and try to quickly rip off the headset as in-game death approaches. We’re pretty sure this isn’t serious, as Luckey himself suggested that it was more of an office art thing, but you never know what extremes a “three commas” net worth can push someone to.

There’s light at the end of the Raspberry Pi supply chain tunnel, as CEO Eben Upton announced that he foresees the Pi problems resolving completely by this time next year. Upton explains his position in the video embedded in the linked article, which is basically that the lingering effects of the pandemic should resolve themselves over the next few months, leading to normalization of inventory across all Pi models. That obviously has to be viewed with some skepticism; after all, nobody saw the supply chain issues coming in the first place, and there certainly could be another black swan event waiting for us that might cause a repeat performance. But it’s good to hear his optimism, as well as his vision for the future now that we’re at the ten-year anniversary of the first Pi’s release.

Continue reading “Hackaday Links: November 13, 2022” →

A man removing a module from a 1960s computer

Ancient Nuclear Plant Computer Finds New Home In Bletchley Museum

October 3, 2022 by Robin Kearey 20 Comments

Although technology keeps advancing every year, safety-critical systems in factories and power plants typically stay with the technology that was available when they were built, in the spirit of “don’t fix it if it ain’t broke”. When it comes to safety, there are probably few systems more critical than nuclear power plants, and as a result one power station in Dungeness, in the south-east of England, was controlled by the same Ferranti Argus 500 computer from the early 1970s until the reactor was shut down in 2018.

The national Museum of Computing in Bletchley was lucky enough to be allowed to scavenge the old computer from the decommissioned plant, and volunteers at the museum have managed to get it running again in its new home. They describe the process in the video embedded below, and demonstrate a few features of this rather unique piece of 1970s technology.

The computer consists of several large cabinets that house enormous PCBs full of diode-transistor logic (DTL) chips, made by Ferranti itself. It comes with 32 kilo-words, or 96 kilobytes, of magnetic core memory, and was designed to run programs stored on punched tape. However, the paper tape reader was removed at some point in the computer’s life and replaced with a PC-based system that emulates the tape reader’s output through its parallel port. This was probably sometime during the 1990s, judging from the fact that the https://hackaday.com/tag/magnetic-core-memory/PC runs OS/2.

Setting up the computer in its new home was complicated by the fact that hundred of cables had to be disconnected in order to move the system out of the power plant. With the help of decades-old documentation, and the experience of one volunteer who used to be a Ferranti engineer, they eventually got it into a state where it could run programs again.

Ultimately, the Argus 500 will be turned into a live exhibit that will simulate a power station alongside another computer that was rescued from a different nuclear plant. Depending on the availability of some parts that are still missing, this might happen later this year, or perhaps next year. In any case, the museum already has a collection that’s well worth visiting if you’re in the area. The story of how they rescued a neglected IBM 360 also makes for fascinating reading. Continue reading “Ancient Nuclear Plant Computer Finds New Home In Bletchley Museum” →

Frequency Counter Restoration Impeded By Kittens

August 24, 2022 by Al Williams 12 Comments

We think of digital displays as something you see on relatively modern gear. But some old gear had things like nixies or numitrons to get cool-looking retro digital displays. The HP 521A frequency counter, though, uses four columns of ten discrete neon bulbs to make a decidedly low-tech but effective digital display. [Usagi Electric] has been restoring one of these for some time, but there was a gap between the second and third videos as his workshop became a kitten nursery. You can see the last video below.

In previous videos, he had most of the device working, but there were still some odd behavior. This video shows the final steps to success. One thing that was interesting is that since each of the four columns are identical, it was possible to compare readings from one decade to another.

However, in the end, it turned out that the neon bulbs were highly corroded, and replacing all the neon bulbs made things work better. However, the self-check that should read the 60 Hz line frequency was reading 72 Hz, so it needed a realignment. But that was relatively easy with a pot accessible from the back panel. If you want to see more details about the repair, be sure to check out the earlier videos.

We love this old gear and how clever designers did so much with what we consider so little. We hate to encourage your potential addiction, but we’ve given advice on how to acquire old gear before. If you want to see what was possible before WS2812 panels, you could build this neon bulb contraption.

Continue reading “Frequency Counter Restoration Impeded By Kittens” →

Re-reclaimed From Nature: Resurrecting A DT80 Terminal

July 30, 2022 by Sven Gregori 6 Comments

When Datamedia announced their new DT80 terminal as a VT100 killer back in 1979, they were so confident of its reliability, they threw in a full one-year warranty. Now, decades later, that confidence is once more put to the touch after [RingingResonance] fished one such terminal out of a creek by an old illegal dumping site. Not knowing what to expect from the muck-ridden artifact, his journey of slowly breathing life back into the device began.

Considering the layers of mud and roots already growing all over the main board, one can only assume how long the terminal has actually been in there. But cleaning it from all that was only the beginning: some components were missing, others turned out to be broken, including some of the ROMs, which [RingingResonance] speculates may have been caused by lightning which determined the DT80’s fate in the first place.

That’s when the adventure really started though, digging deep into the terminal’s inner life, eventually writing a debugger and own firmware for it. That code, along with all other research, notes, and links to plenty more pictures can be found in the GitHub repository, and is definitely worth checking out if you’re into the technologies of yesteryear.

Despite the DT80’s claimed superiority, the VT100 prevailed and is the terminal that history remembers — and emulates, whether as tiny wearable or a full look-alike. But this fall into oblivion was also part of [RingingResonance]’s motivation to keep going forward restoring the DT80. Someone had to. So if you happen to have anything to contribute to his endeavours or share with him, we’re sure he will appreciate you reaching out to him.

Continue reading “Re-reclaimed From Nature: Resurrecting A DT80 Terminal” →