Reviving A Cursed Sun SPARCstation IPX

March 21, 2026 by Maya Posch No comments

SPARCstation IPX running Solaris 2.6. (Credit: This Does Not Compute, YouTube)

The best part about retro computing is the idea that you’ll save some poor system from being scrapped and revive it to a working state, at which point you can bask in the glory of a job well done. That’s when reality often strikes hard, and you find yourself troubleshooting a maddening list of issues as you question everything about your life choices. Such was the case with [This Does Not Compute] over at YouTube with a Sun SPARCstation IPX that decided to put up a big fight.

This is the second video of a series. In the first installment, the PSU was repaired, and a boot failure was diagnosed. The system’s onboard diagnostic led to the assumption that one of the 8 kB SRAM ICs was defective. You can readily get SRAM replacements, so it seemed to be an easy fix. Unfortunately, the fun was only beginning as the system reported the exact same error after the SRAM was replaced.

After flipping a virtual table, the mainboard was swapped with a donor one from a scrapped laptop system. With this, it booted, but the video output showed only vertical lines. Obviously, the solution here was to insert a replacement video card, which not only fixed the display output but also demonstrates once again that you can fix many vintage computing issues by simply replacing hardware.

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ESP32: When Is A P4 A P4, But Not The P4 You Thought It Was

March 21, 2026 by Jenny List 4 Comments

We’re used to electronic parts of the same type staying predictably the same, sometimes over many years. An early Z80 from the mid 1970s can be exchanged with one from the end of production a few years ago, for example. This week, we’ve had DMs from several readers who’ve found that this is not always the case, and the culprit is surprising. Espressif has released a new revision of their P4 application processor, and though it’s ostensibly the same, there are a couple of changes that have been catching people out.

The changes lie in both hardware and software, in that there’s a pin that’s changed from NC to a power rail, a few extra passives are needed, and firmware must be compiled separately for either revision. The problem is that they are being sold as the same device and appear in some places under the same SKU! This is leading to uncertainty as to which P4 revision is in stock at wholesalers. We’ve been told about boards designed for the old revision being assembled with the new one, a situation difficult to rework your way out of. Designers are also left uncertain as to which firmware build is needed for boards assembled in remote factories.

The ESP32-P4 is an impressive part for its price, and we’re sure that we’ll be seeing plenty of projects using this new revision over the coming years. We’re surprised that it doesn’t have a different enough part number and that the wholesalers have seemingly been caught napping by the change. We’re told that some of the well-known Chinese assembly houses are now carrying the two chips as separate SKUs, but that’s scant consolation for a designer with a pile of boards carrying the wrong part. If you’re working with the P4, watch out, make sure your board is designed for the latest revision, and ask your supplier to check which chips you’ll get.

If the P4 is new to you, we’ve already seen a few projects using it.

Analog Siren For Psychedelic Soundscapes

March 21, 2026 by Bryan Cockfield 1 Comment

For better or worse, there are a few instruments that have been pigeonholed into specific genres of popular music. For example, banjos are often heard in bluegrass or folk, harmonicas in blues, and a sick horn section will take many of us immediately to third wave ska. Similarly, there are certain styles of synthesizers tied to various genres and if you’re a fan a certain sub-genre of reggae you’ll be familiar with the dub siren. This unique analog synth has a few tricks up its sleeve and [Jakub] shows us how he built his.

He’s calling this build the Sirenotron, and its based on the venerable 555 timer It also features an LFO built on an LM358, with triangle and square wave modes, plus an additional “acid mode” for the square wave which adds a single capacitor to the circuit but makes a big difference in the sound. Like any siren synth, there are potentiometers to control pitch and the pulse rate of the siren as well and another switch controls whether it is outputting sound or not. He’s also included the ability to control it with a foot pedal so he can use it while playing the bass guitar during live shows.

[Jakub] has gone through several prototypes before getting to this stage, and not only uses it when playing dub but also creates psychedelic soundscapes in a side project of his where it also fits right in. He’s also made the schematics available for anyone who wants to reproduce it or build on his design.

We’re always interested in a unique synthesizer build around here, and some of our favorites include this synth built from Sega Genesis parts and this one controlled more like a woodwind instrument.

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The Unreasonable Power Density Of Lithium-Ion

March 21, 2026 by Elliot Williams 31 Comments

We’re all used to it by now, but I’d just like to reflect on how insanely power-packed lithium ion batteries are, and everything that’s afforded us. I’m trying to think of a gadget, a hobby, or nearly anything in my house that’s not touched by the battery chemistry.

I’m looking at my portable wireless keyboard in front of me, with a LiPo pack inside. Oddly enough, I’m charging it with a LiPo-based power bank, simply because the cable to the nearest USB-C adapter is too short. A gaming console, cell phone, and a DSLR camera are all within arms reach and powered with lithium.

It’s not just consumer stuff either. I fly FPV quads and airplanes for fun when I can, and of course those are made entirely possible by the combination of smaller brushless DC motors and their drivers, and the high-power-density LiPo packs that power them. For field recharging, I have a huge self-made LiIon pack that can keep them all in the air all day. These days, LiPo and LiIon tech is the heart of hacker projects big and small. Heck, we even powered this year’s Hackaday Supercon badge with a LiPo that allowed it to run all weekend on a charge for many folks, where in the past swapping out AAs during the event was commonplace.

The application that still blows my mind is that we recently got a solar installation on our roof, which means a huge LiFePo battery in the basement. And while it’s one thing to power noisy little quads on the battery tech, it somehow seems another to power our entire house, for multiple hours per day, from a battery. Granted it’s not a couple of AAA cells in a little black plastic box, but it’s simply amazing to run a washing machine, the fridge, the stove, and even the heating off of what amounts to a battery pack.

Of course, I’m aware of the costs of producing the cells, both in terms of money and the environmental damage. It’s not a free lunch, and I’m looking forward to both cleaner and cheaper energy storage chemistries in the future. But for now, I’m still in awe of the many options that lithium-based battery chemistry has brought us. May your pillows remain non-spicy!

Resin Injection CRT Cataract Surgery On Macintosh Monitor

March 21, 2026 by Tyler August 6 Comments

Nothing lasts forever, but you’d think the leaded-glass face of a CRT would not be a place you’re likely to see Father Time causing failures. Alas, the particle accelerators we all lovingly stared at were very often not unitary pieces of glass: in case of implosion, safety glass was glued onto the front of the CRT. That glue will inevitably fail, as happened to the 20″ Mac-branded Triniton [Epictronics] had with a PowerPC 6100 that needed a few other repairs.

His version of cataract surgery was the most interesting. Usually cataracts are an issue for much older CRTs than the 90s-era Macintosh display featured here, but this particular display was literally pulled out of the trash and not stored well before that, so that’s probably what accounts for its accelerated aging. Usually what people do with CRT Cataracts is use heat to remove the safety glass and failing adhesive. [Epictronics] has a safer technique, however: inject fresh adhesive into the gap that’s forming around the edge of the display.

With a syringe and UV cure resin, he slowly and laboriously goes around the edge of the display to fill in the bubbles that can be reached. Luckily, the delamination on this CRT doesn’t extend very far beyond the edges, so a standard syringe tip could reach all the problem areas.

It looks good now, but if it doesn’t hold, [Epictronics] points out he can still remove the glass with the traditional hot-air technique. We hope it holds up; this is a nice technique to try if you have a CRT with the early stages of cataract delamination. For future reference, it took about one milliliter of resin to fill each square centimeter of affected area, which implies the cataract gap is quite small indeed.

Having repaired the monitor by about fifteen minutes into the video, [Epictronics] spends the remaining seventeen minutes getting the Mac running with its original CD-ROM drive (that needed recapped) and a DOS compatibility card.

We’ve featured [Epictronics] repairs here before, like when he tore down and rebuilt an IBM Model F keyboard.

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3D Printed Clock Just Taps It In

March 21, 2026 by Bryan Cockfield 2 Comments

The famous cuckoo clock, with its moving, chirping mechanical bird indicating various divisions of time, has been around since at least the 1600s. The most famous of them come from the Black Forest area of Germany, and are still being made worldwide even today. Other clocks with different themes take their inspiration from the standard bird-based clocks from history, and thanks to modern 3D printing and other technologies we can make clocks with almost any type of hour indicator we’d like with relative ease like [Jason]’s golf clock.

While the timekeeping mechanism is a fairly standard analog clock, the hour indicator mechanism in this build is a small figure which putts a golf ball into a hole once every hour. It uses an ESP32-C3 at its core, which controls a pair of servos. One controls the miniature golfer, and the other lifts the ball up into position on the green at the appointed time. Once the ball is in place, the figure rotates, striking the ball towards the hole. Although it looks almost like the ball is guided by a magnet of some sort at first glance, the ball naturally finds its way into the hole by the topography of the green alone.

Almost all of the parts in this build are 3D printed, including the green, the golfer, the frame, and a number of the servo components. There’s also a small sensor that detects if the ball has actually made it into the hole and back to the lifting mechanism, and to that end there’s also a number of configurations that can be made in the software to ensure that the servos controlling everything all work together to putt the ball properly.

While not a cuckoo clock in the strict sense, we always appreciate a unique clock around here, but if you demand your clocks have ideological purity we’ll point you to this cuckoo clock built into a wristwatch.

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Portable CRT TV Becomes Retro Cyberdeck

March 20, 2026 by Lewin Day 3 Comments

These days, it’s pretty easy to slap together a single-board computer and a cheap LCD screen to whip up a cool cyberdeck fast. But what if you wanna go more retro? [Manu] found a portable TV straight out of the original Blade Runner film, and decided this would be the perfect base for a cyberdeck rocking a whole-ass CRT screen.

The build started with a Panasonic TR-545 television. Back in the day, it took many large batteries to power this thing up—no surprise given how power hungry CRTs are. This gave [Manu] a neat opportunity to sneak all the new cyberdeck hardware into the original battery tray, including a new lithium-ion battery pack that is much more compact than the original. A Raspberry Pi 5 is running the show, computer-wise, and it’s hooked up to an HDMI RF modulator that allows the video output signal to be hooked up to the TV’s original antenna input. It’s not the cleanest way to go, but it allowed [Manu] to make the mod entirely reversible. All the new hardware slots neatly into the repurposed battery tray, and can be removed quite easily without damage to this vintage specimen. Even the keyboard fits nicely into the setup, as [Manu] was able to find a suitable 60% layout foldable unit right off the shelf.

Check out the slide deck for more details on the build, but be warned—it’s a 241 MB PDF. Bonus points if you calculate what that would cost to store on a hard drive in 1979 when the Panasonic TR-545 was on the market. We’ve seen a similar build before, too, with a classic black & white Magnavox unit. If you like squinting at a tiny blurry screen, a CRT cyberdeck is absolutely the way to go. Just be warned that the other screenwriters at your local coffee shop will be more interested in your hardware than whatever you’re actually working on. Good luck with your next pitch all the same. Video after the break.

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