Learning About Ground Loop Isolators Thanks To A Scam Product

June 15, 2026 by Maya Posch 35 Comments

When [Denki Otaku] bought a ¥1,200 (roughly €6.5) XLR ground loop isolator off Japanese Amazon, he initially didn’t suspect that anything was off. Since they’re fairly simple devices, with basically a 1:1 transformer per channel in some kind of enclosure, the price wasn’t unreasonable.

That’s before a teardown showed that this ‘ground loop isolator’ actually contains direct wiring between the XLR sockets, but that doesn’t mean that you cannot still make an educational video about the real devices.

First the basic theory is explained, before the fake ground loop isolator is subjected to an analysis, showing why you’d want to use the real deal. Of course, detecting a fake one is pretty easy, as a simple continuity test with a multimeter or similar will show that DC passes right through the fake isolator.

Next a real ground loop isolator was designed with a custom PCB and a high-pass filter added to the feature list. Here rather than a very basic filter with cheapo parts there was definitely some gold-plating going on, but it does show what you can do in addition to just adding a few simple transformers for ground isolation purposes.

The finished ground loop isolator device is pretty large, and would definitely require a larger enclosure than the homeopathic device, but it makes for an easy test bed with convenient access during the subsequent analysis.

Here each of the two channels has its own transformer and filter, with an initial test just by ear making the injected 2 kHz noise signal appear to go completely away.

Next, an oscilloscope is used to visualize the functionality, with the non-isolated 440 Hz test signal first shown with and without the injected noise, showing the clear impact of the noise and subsequently the isolator.

Of course, high-frequency noises will still pass through the transformer via parasitic capacitance leakage between the windings, so it’s not a silver bullet. Here the analysis at the end of the video shows the noise-rejection characteristics of these isolators, and why adding a high-pass filter makes a lot of sense. Finally, the scam device’s XLR connectors were reused in an enclosure for this custom board, giving it some purpose after all.

Continue reading “Learning About Ground Loop Isolators Thanks To A Scam Product” →

The Air Position Indicator For The B-29

June 12, 2026 by Al Williams 25 Comments

When you think of a computer, you probably don’t think of a tube full of motors and mechanics. However, as [Our Own Devices] shows, the Bendix AN5841 API Computer, an air position indicator computer, is exactly that. Using mechanical integrators and data from other analog systems on an airplane to provide key flight data to a pilot. You can see the video below.

These devices were made for military aircraft, including the B-29. It is odd that speed data can be derived from a pump that balances pressures using a fan. The video does a good job of explaining exactly how that works.

Continue reading “The Air Position Indicator For The B-29” →

As It Turns Out, There’s More Than One Cassette Mechanism Being Made After All

June 5, 2026 by Tyler August 8 Comments

It’s become an accepted truth amongst tapeheads that there’s no point looking at new hardware, because there’s only one tape mechanism being made anywhere in the world anymore, and that it sucks. [VWestlife] may enjoy German automobiles, based on the name, but he’s also a tapehead– and he took the time to demonstrate on YouTube that the accepted truth just ain’t so.

The supposed One Mechanism to Rule Them All in Lo-Fi is designed or made by Chinese company Tanishin. Certainly Tanishin does make a tape mechanism, but as [VWestlife] demonstrates with a few teardowns, there’s absolutely more than one on the market. That doesn’t mean any of the new offerings will out-compete your vintage Sony Walkman, but it does mean there are differences worth considering if you were to buy new.

Note that it is handhelds like the Walkman being talked about– it must be, since there are both slot-loading and flip-loading decks still being made, and even if you’re not a tapehead you should be able to tell that those won’t share the same part on the BOM.

With a few teardowns, he finds three separate mechanisms, followed by a deep-dive into the Tanishin. If you’re looking to buy a new walkman– or perhaps use its guts to build a mass storage device-– you might want to watch the whole thing to help you pick. On the other hand, the mechanism doesn’t matter that much, as he points out. It brings the tape over the head, but that’s not difficult. Everything else– from the motor that needs to draw the tape out evenly, to the pickup and the preamps and amplifiers–is where noise and poor quality sound tends to creep in, especially when something’s built to a budget.

Overall, [VWestlife] takes pains to point out that these ‘crappy’ new players aren’t any worse than the original Sony Walkman– we’ve just been spoiled by decades of better media than the humble compact cassette. That’s no slight against the cassette– people are still pushing its limits to this day, like this insanely fast vacuum-driven mechanism we featured.

Thanks to [Stephen Walters] for the tip!

Continue reading “As It Turns Out, There’s More Than One Cassette Mechanism Being Made After All” →

Inside Dyson’s Over-Engineered ₤1000 Hand Dryer

May 27, 2026 by Maya Posch 56 Comments

It seems fair to say that Dyson sits at the intersection of impressive engineering and borderline ridiculous products. The Dyson Airblade 9KJ hand dryer that [ElectrArc240] recently took to bits would definitely seem to fall under the latter, combining an incredible amount of engineering all for the simple task of drying wet hands.

These hand dryers are rated for a cool 900 Watts, with an 0.5 W standby power consumption, though you can also switch it to a 650 W ‘eco mode’ when installing it. The air that gets sucked into the dryer first passes through a HEPA filter before it hits the heating element and then gets blown out of the handles onto one’s hands.

Both of these handles come with a presence sensor in the form of an ST VL53L3CX time-of-flight sensor, along with a path for the heated air towards the thin slits. Returning to the section just past the HEPA filter is the compressor, with a rather fancy airflow path that involves various stacked meshes. As can be seen in the video, where you’d expect basically a simple blower motor or so, there is a truly astounding amount of parts as the teardown progresses.

The motor disassembly is the first part where some desoldering and breaking of glue bonds is really necessary, but it gives full access to the driver board. The circuit used here is your typical IGBT-based driver, though with a mystery PIC MCU to do things. Following this the tear-down turns fully destructive, giving access to the motor internals.

Following an analysis of these internals we marvel at the carbon-fiber rotor that keeps the single magnet in one piece. This is another engineering choice that serves to justify the 1,000 quid price tag. All so that rest room visitors do not have to suffer the humility of using paper towels.

Continue reading “Inside Dyson’s Over-Engineered ₤1000 Hand Dryer” →

Spacelab’s Mitra 125 MS

May 24, 2026 by Al Williams 4 Comments

[Ken Shirriff] does some of the most interesting teardowns. This time, he’s looking at a French-built minicomputer called the Mitra 125 MS from around 1980. In particular, it was the computer inside Spacelab, a European lab that could fit in the back of the Space Shuttle.

As you might expect, the computer doesn’t contain a microprocessor. Instead, it is a series of cards and, in this post, [Ken’s] looking at the ALU that allows the computer to perform math operations.

Continue reading “Spacelab’s Mitra 125 MS” →

Teardown: ChargeTab Emergency Phone Charger

May 14, 2026 by Tom Nardi 58 Comments

If you own a modern smartphone, there’s an excellent chance that its battery has run dangerously low on you at least a few times. Murphy’s Law dictates that this will naturally occur at the worst possible moment, say when you need to make an important phone call or when you’re lost and need to navigate home.

With this in mind, it’s not hard to see how a product like the ChargeTab would have a certain appeal. A small $10 USD device that you can keep in the car or pack in a bag that’s always available to charge your phone in an emergency.

Because it’s not meant to be used regularly — indeed it may never get used at all — it’s not completely unreasonable that such a device would only be good for one or two charges before its spent and must be replaced. It’s a bit like keeping a road flare in the car; it’s unlikely you’ll ever use the thing, but if you do, it only needs to work once.

But then what? According to ChargeTab, once the gadget has depleted its internal ~3,000 mAh battery it cannot be recharged and is no longer usable. Now to be fair, they specifically tell you to not throw it in the trash. They’ll send you a free return label to ship it back to them, at which point it will be refurbished and put back into circulation. The company argues that this recycling program, combined with the fact that the batteries inside the ChargeTabs were supposedly diverted from landfills in the first place, makes their entire operation eco-friendly.

Yet here we have a pair of ChargeTabs that were thrown in the regular garbage and would have taken a one-way trip to the local landfill if it wasn’t for the fact that I habitually dig through garbage cans like a raccoon. So let’s take a look at what’s inside one of these emergency phone chargers and if the idea is as green as the company claims.

Continue reading “Teardown: ChargeTab Emergency Phone Charger” →

Trying To Fix A GoPro Hero 10 With A No Camera Input Issue

May 12, 2026 by Maya Posch 4 Comments

In the search for more exciting broken electronics to repair, [Hugh Jeffreys] bought a GoPro Hero 10 for US$100 with an apparently rather common issue of no camera input, along with a cracked display. This particular camera issue is rather obvious, with just darkness where the camera’s input should appear on the display. Since [Hugh] already needed a spare display, he figured that he might as well get an even more broken GoPro Hero 10 for parts.

Another US$40 later, [Hugh] found himself the proud owner of a second GoPro, this one being water damaged and no longer turning on. Getting to the internals requires removing the glued-in display, which is even trickier than with a smartphone. By inserting a thin blade, adding solvents and not prying, you can slowly work it loose.

With two disassembled GoPros it was now possible to swap modules. After a factory reset and firmware update had failed to fix the first GoPro, the camera module from the donor unit was inserted, but this made no difference. Amusingly, after cleaning the water-damaged unit’s PCBs, it was found to be in good working condition, so ultimately the second GoPro was repaired, leaving the ‘no camera input’ issue undiagnosed.

It’s possible that a board-level repair on the first unit can address the original issue, but without schematics this would likely entail a lot of blindly poking around, in the hope of finding a damaged MLCC or other obvious fault. There is also the possibility that this is a firmware issue, with some reporting luck mashing the record button, but others disagree.

Since [Hugh] did do the firmware reset and updating steps, and even inserted a whole new working camera module, it would seem to narrow the problem down to a board-level issue. Whatever the case may be, it’s a frustrating issue with a rather expensive device.

Continue reading “Trying To Fix A GoPro Hero 10 With A No Camera Input Issue” →