Fixing A Cotton Candy Vending Machine

May 16, 2026 by Maya Posch 7 Comments

Cotton candy is probably the best way to eat pure sugar, which makes having your very own cotton candy vending machine to automate making it a bit of a dream. The machine that [Block’s Retro Repairs] got should therefore make him very happy, but unfortunately it was bought as defective. After digging into the machine in an earlier video, this time around there’s some actual success and proper cotton candy to enjoy.

The PCB with the rather frayed temperature sensor. (Credit: Block's Retro Repairs, YouTube) — The PCB with the rather frayed temperature sensor. (Credit: Block’s Retro Repairs, YouTube)

The way that cotton candy is made involves spinning thin threads of sugar, which are created by the heating and rapid crystallization of the sweet stuff. Unfortunately this machine wasn’t even really extruding sugar any more, so it had to get a deep clean to remove probably years of crusty buildup. After this things still weren’t working right, although cranking up the temperature on the induction heated head improved the results somewhat.

To really fix the machine, this head with its clearly dodgy thermocouple had to be disassembled. This revealed that said sensor was looking rather frayed, potentially shorting out against the aluminium head and likely not in the entirely right position any more. After adding some insulation back and making sure that the thermocouple was located closer to the top of the head, it was time for more testing.

Repairing the thermocouple seems to have fixed most ills, with still some calibration of the temperature required, but finally resulting in fancy shaped cotton candy in its myriad of colors. Along with the looming hazard of potentially acquiring Type II diabetes from all the testing, there was still a problem involving the remote management feature of this Red Rabbit machine.

These $6,000 vending machines do feature an Android 7-based software with a Rockchip SoC and access to a lot of settings via its large touch screen, but features such as setting prices for the products are locked away via a remote account. The machine was sadly still linked to someone else’s account, and so far Red Rabbit support had not responded to any documentation, repair help or account unlinking requests. This has left the machine in somewhat of a pickle.

It was possible to dump the software of the machine, which can be fetched from Archive.org, so if anyone would like to pitch in and break this remote lock, that would be very welcome. It’s also considered to replace the cash reader with a simple button or so, but where’s the fun in that?

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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.

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Debugging A Stopped Foucault Pendulum’s Electronics

May 2, 2026 by Maya Posch 17 Comments

After the Foucault pendulum at the Houston Museum of Natural Science stopped working a while back after maintenance on the building, workers set out to determine what was wrong with the mechanism that normally keeps it in motion. Fortunately, it turned out that all they had to do was fiddle with some knobs to get everything dialed back in proper-like.

When we previously covered this dire event, it was claimed that this was a one-off system, hacked together by some random bloke. But as can be seen in the video and further detailed in the comments to the video the reality is far more interesting.

This particular Foucault pendulum is one of many that were created by the California Academy of Sciences, with hundreds of them installed throughout the US and possibly elsewhere. That said, since a pendulum of any description will never be a perpetual motion device, the electromagnet installed near the top of the installation has to carefully add some kinetic energy back that was lost due to friction as the pendulum moves around.

Sadly the video doesn’t go into much detail on what exactly was wrongly configured with this particular pendulum. Keeping a weight at the end of a long cable moving around at a set velocity is a tricky business, so it’s little wonder that getting some parameters wrong would engage and disengage the electromagnets at the wrong times and making the pendulum stop swinging.

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Dyson Vacuums And The Curse Of Cooked Capacitors

April 26, 2026 by Maya Posch 44 Comments

It seems to be becoming a bit of a theme that consumer electronics are dying not due to some critical fault, but due to Cooked Capacitor Syndrome (CCS). Case in point, Dyson handheld vacuums and the capacitors on its driver board. After having his $800 Dyson V15 handheld vacuum die after two and a half years of regular use, [LeftyMaker] found himself elbows-deep in the dusty innards of the vacuum just to replace some capacitors.

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Repairing A Mercedes EQC 300 BEV Battery

April 22, 2026 by Maya Posch 15 Comments

When [OGS Mechanics] got a Mercedes EQC 300 battery-electric car in for repair, it was found to have a bit of a weird issue: after sitting in a garage for a while, its range on battery had suddenly reduced significantly without clear cause. Although the typical response here is to just mark the battery pack as ‘faulty’ and replace the whole unit, [OGS] decided to dig into the pack to see what was going on.

The short version is that this particular battery pack consists of two individual batteries, each with its own BMS, one of which had reported a condition to the master BMS that triggered the ‘replace battery module’ error observed with the scan tool. From this it could also be seen that the first battery was at a 10% state-of-charge (SoC), and the second at 95%, making them incredibly unbalanced. Unfortunately the dealer procedure to rebalance did not work here, with only the second battery wanting to charge even after draining both to the same initial level.

To diagnose the underlying issue in earnest required gently prying open the battery pack like a massive glued-shut smartphone. Going by the theory that it is a software glitch, since the first battery was still at a healthy voltage level, it was decided to manually charge it. With both batteries now fully charged, the BMS for the first battery was then removed to have its memory overwritten with that of a known good BMS module, clearing the ‘replace battery module’ error.

Although in the preview for the next video it’s hinted that there’s also an internal balancing issue in the first battery pack, this could be another symptom of its BMS glitching out. Either way, it would seem that BEVs battery modules are both heavily dependent on software, as well as afflicted by the same throw-away culture that has people just buying a new smartphone when the battery fails.

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Fixing A GameCube’s Dodgy Optical Drive With Fresh Capacitors

April 17, 2026 by Maya Posch 3 Comments

Generally when a game console with an optical drive stops reading discs the first thing that people do is crank on the potentiometer that controls the power to the laser diode to ramp up its output. While this can be a necessary solution to eke out a bit more life out of a clearly dying laser diode, this can actually massively shorten the lifespan of a good diode that’s just held back by bad capacitors. This is demonstrated by [Skawo] with a fix on a GameCube that stopped reading discs.

While it’s absolutely true that laser diodes have a limited lifespan, so do the capacitors and other components in the system. Thus, after tearing down this Japanese GameCube, [Skawo] accesses the optical PCB for some delicate plier-based capacitor surgery. One can absolutely question such violence, as well as the replacement mix of MLCC ceramics and a stray THT electrolytic capacitor, but the results after reassembly are obvious.

Without having to adjust the laser diode’s potentiometer, the game console now happily reads the game disc while the laser diode breathes a sigh of relief. Although all GameCube consoles will face the inevitable demise of their optical drives – barring a replacement optical pickup solution appearing – with this capacitor replacement solution it’s at least possible to stave off that undesirable time for a bit longer.

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Heathkit Tuner Saved From Junk Pile

April 4, 2026 by Al Williams 4 Comments

We miss the old Heathkit. You could build equipment that rivaled or even surpassed commercial devices. The cost was usually reasonable and, even if you could get by with less, the satisfaction of using gear you built yourself was worth a lot. Not to mention the knowledge you’d gain and your confidence in troubleshooting should the need arise. So we were jealous of [RCD66] when he found a Heathkit AJ-43C stereo tuner in the recycle bin.

As you can see in the video below, it needed a lot of love to get back to its former self. The device dates from around 1965, when the kit cost $130. In 1965, that was a lot of money. Back then, that would have bought you about four ounces of gold and would have been a great down payment on a $1,500 VW bug.

Things were a bit of a mess, so he removed all the parts and replaced most of them. Unsurprisingly, the electrolytic capacitors all tested bad. The transistors were all germanium, but if they tested good, his plan was to reuse them. There were several PCBs inside, and he made some changes, such as replacing the zener diode power supply with something more modern.

How did it sound? Watch the video and see for yourself. We usually like troubleshooting specific problems on gear like this, but in this case, it was probably smart to just do a total rework.

Heathkit had quite an origin story. This isn’t the first time we’ve seen someone strip and rebuild a Heathkit.

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