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.

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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.

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Tiny Arcade Uses Tiny CRT

July 27, 2022 by Bryan Cockfield 16 Comments

Restoring vintage electronics is a difficult hobby to tackle. Even the most practical builds often have to use some form of modern technology to work properly, or many different versions of the machine need to be disassembled to get a single working version. Either way, in the end someone will be deeply hurt by the destruction of anything antique, except perhaps with [Marco]’s recent tiny arcade with a unique CRT display.

The CRT is a now-obsolete technology, but Arcade and MAME purists often seek them out because of the rounded screen and vintage feel these devices have when compared to modern LCD or LED displays. For a build this small, though, [Marco] couldn’t just use parts from an old TV set as there wouldn’t be clearance in the back of the cabinet. An outdated video conferencing system turned out to have just the part he needed, though. It has a CRT mounted perpendicularly to a curved screen in order to reduce the depth needed dramatically.

The final build uses a tiny Namco system meant to plug into the RCA jack on a standard TV, but put in a custom case that makes it look like an antique video game cabinet. It’s an interesting build that doesn’t destroy any valuable antique electronics, while still maintaining a classic arcade feel. If you’re building a larger arcade cabinet which will still satisfy the purists out there, make sure you’re using a CRT with the right kind of control system.

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Restoring $5 Busted Synthesizer Made Easy, Thanks To Thermal

July 16, 2022 by Donald Papp 19 Comments

[D. Scott Williamson] paid $5 for a Roland JV-30 synthesizer at a garage sale. Score! There was only one catch: it didn’t work and didn’t include the power supply. Luckily, restoring it was made easier by breaking out a thermal camera.

As mentioned, the keyboard was missing a 9 VDC power supply (rated 800 mA) with a center-negative barrel connector. Slightly oddball, but nothing an enterprising hacker can’t deal with. After supplying power with a bench supply, not only did the keyboard not come to life, but the power supply clamped the current draw at 1.5 A! Something was definitely not right.

This shorted glass-bodied diode might look normal to the naked eye, but thermal imaging makes it clear something’s amiss.

Inside, there was no visible (or olfactory) sign of damage, but looking closer revealed that a little SMT capacitor by the power connector was cracked in two. Fixing that didn’t bring the keyboard to life, so it was time to break out the thermal imager. Something was soaking up all that current, and it’s a fair bet that something is getting hot in the process.

The culprit? The reverse polarity protection diode was shorted, probably as a result of damage by an inappropriate power supply or a surge of some kind. Replacing it resulted in a working keyboard! Not bad at all for $5, a diode, an SMT cap, and a little workbench time. The finishing touch was replacing a missing slider knob, which took some work in OpenSCAD and a 3D printer. Overall, not bad!

Thermal imaging used to be the stuff of staggering price tags, but it’s downright accessible these days, and makes it easy to spot things that are hot when they shouldn’t be. And if a thermal camera’s lens isn’t what you think it should be? It’s even possible for a sufficiently motivated and knowledgeable hacker to modify those.

Reverse-Engineering Forgotten Konami Arcade Hardware

June 28, 2022 by Bryan Cockfield 4 Comments

When fully-3D video games started arriving in the early 90s, some companies were more prepared for the change than others. Indeed, it would take nearly a decade of experimentation before 3D virtual spaces felt natural. Even then, Konami seems to have shot themselves in the foot at the beginning of this era with their first foray into 3D arcade games. [Mog] shows us the ins-and-outs of these platforms while trying to bring them back to life via MAME.

These arcade machines were among the first available with fully-3D environments, but compared to offerings from other companies are curiously underpowered, even for the time. They include only a single digital signal processor which is tasked with calculating all of the scene geometry while competing machines would use multiple DSP chips to do the same job. As a result the resolution and frame rate are very low. Nonetheless, [Mog] set out to get it working in MAME.

To accomplish this task, [Mog] turned to a set of development tools provided to developers for Konami in the early 90s which would emulate the system on the PCs of the time. It surprisingly still worked on Windows 10 with minor tweaking, and with some other tools provided over the decades of others working on MAME these old Konami machines have some new life with this emulator support.

Not everything works perfectly, but [Mog] reports that most of the bugs and other issues were recently worked out or are being actively worked on by other experts in the field. If you remember these games from the arcade era of the 80s and early 90s, it might be time to grab an old CRT and fire this one up again.

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TRS-80 Luggable Gets Fresh Face, New Gear

June 16, 2022 by Tom Nardi 10 Comments

It’s true that this TRS-80 Model 4P “luggable” was in better shape than many of the vintage machines that pass through the hands of [Drygol], but that doesn’t make the end result of its refurbishment and upgrade process any less impressive. After all, not every rebuild has to be a once-in-a-lifetime achievement.

No, the case didn’t have to get pieced back together by hand, and the board didn’t need to have half of its traces recreated. But the outer plastic was certainly in need of a good retrobright treatment, the keyboard was overdue for a cleaning, and the capacitors in the PSU were predictably due for retirement. After [Drygol] got through with it, the machine was back in like-new condition. But then, we can do a little better than that…

So into the refreshed computer went several community-developed modifications, including a M3SE expander that adds Compact Flash and Ethernet support to the TRS-80 and a high-resolution Grafyx video board. In classic [Drygol] style, every effort was made to integrate these upgrades as seamlessly as possible. After struggling for a bit to find a 5.25″ drive that would write a disk the TRS-80 would actually read, all the necessary files to get the upgrades working were transferred over, and the system was booting into TRSDOS.

We’ve covered a lot of [Drygol]’s restorations, and never get tired of seeing how these old and broken machines get a new lease on life once they come out the other end. Whether it’s a relatively easy task of swapping out some dud chips, or using every trick in the book to piece together what’s left of a computer’s case, they always show an incredible level of dedication and attention to detail that you can’t help but admire.

The hairclip-embedded tool being used on a Tiger 99x game console, clipped onto a spot where the plastic ribbon meets the LCD panel itself, heating it up

World’s Smallest Hair Straightener For Fixing Old LCD Ribbons

March 19, 2022 by Arya Voronova 8 Comments

[Stephen] writes to us about an LCD repair tool he has created. We’ve all seen old devices with monochrome LCDs connected by thin film, where connections between the PCB and the LCD have deteriorated and the LCD would no longer show parts of the picture. This is a connection heating gadget, that [Stephen] affectionately dubs as World’s Smallest Hair Straightener, made specifically to bring cool old tech back to life.

A resin-printed mold houses a coil of Kanthal wire, easy to source and simple to make. He reuses a hair clip as a housing for the heating element, which also provides pressure needed to squish the film-printed conductive traces into the LCD as the adhesive melts. High-temperature epoxy brings the two together, and with a variable power supply, this tool successfully brought an old Tiger 99x handheld back to life.

This hack was made possible, in part, because of [JohnDevin Duncan] in Hackaday comment section sharing his experience on repairing LCD ribbons back in 2015, giving valuable insights on the problem that we initially thought would be solve-able with a soldering iron. The knowledge shared was distilled by [Stephen] into a tool that we all can now use when we encounter a device we really, really want to revive.

Last time we covered this topic, quite a few hackers popped up with their stories and suggestions. Old game console fix stories are a staple here on Hackaday, a few pop to mind – this high-effort trace repair of a water-damaged GameBoy cartridge, a badly designed NES cartridge socket reinvention, and this GameBoy LCD sunburn damage restoration guide.