A Failed SwitchBot Plug Mini And Cooking Electrolytics

February 7, 2026 by Maya Posch No comments

Poorly designed PCBs and enclosures that slowly cook the electrolytic capacitors within are a common failure scenario in general, but they seem especially prevalent in so-called Internet-of-Things devices. The SwitchBot Plug Mini that [Denki Otaku] took a look at after many reports of them failing is one such example.

The location of the failed electrolytic cap in the SwitchBot Plug Mini. (Credit: Denki Otaku, YouTube)

These Mini Plugs are ‘smart’ plugs that fit into a regular outlet and then allow you to control them remotely, albeit not integrated into a wall or such like the Shelly 2.5 smart relay that also began dying in droves. Yet whereas with the Shelly relays this always seemed to take a few years to show up, generally in the form of WiFi connectivity issues, these SwitchBot plugs sometimes failed within weeks or start constantly switching the relay on and off.

After SwitchBot started an exchange program for these plugs, [Denki Otaku] decided to examine these failed devices from affected users. Inside a dead unit the secondary side’s 680 µF capacitor was clearly bulging and had cooked off its electrolyte as a teardown of a dead capacitor confirmed. After replacing this one capacitor a formerly unresponsive plug sprung back to life.

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Fixing Sony And Philips’ Doomed CD-i Console

February 1, 2026 by Maya Posch 12 Comments

Although not intended to be a game console, the CD-i would see a a couple of games released for it that would cement its position in gaming history as the butt of countless jokes, some of which still make Nintendo upset to this day. That aside, it’s still a fascinating glimpse at the CD-based multimedia future envisioned in the early 90s, starting with its release in 1990. Recently [MattKC] decided to purchase another CD-i in a fit of nostalgic rage, and repair it to show the world what the future could have been like.

Although Sony and Philips co-developed the device, Sony would go on to release the PlayStation a few years later, which made the CD-i’s life and expectations for it that much harder, leading to it slowly fading into history. The Magnavox one that [MattKC] got is one of the later models, based on the CD-i 450 that was introduced in 1994 as one of the more gaming-oriented models.

As is typical with older devices that use optical media, it would not read discs. It also would sometimes boot up with a ‘Memory Full’ error. This is a common fault due to the built-in battery having run out, erasing RAM-stored values and causing random glitches like this when garbage values were read in on boot.

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Servicing The ‘Not Serviceable’ Bearings On A Vacuum Power Head

January 27, 2026 by Maya Posch 12 Comments

Everyone knows that bearings are a consumable wear item, and that the power head of a vacuum likely contains bearings that will eventually need to be replaced. Yet when the manufacturer wants you to toss out the entire roller and pay $80 for the privilege, that feels rather steep and unnecessary. In the case of [Mark Furneaux], the roller in the power head of his Filter Queen brand vacuum felt particularly over the top to toss, since it’s all fancy wood with very durable brushes.

One of the bearings had stopped being a bearing, resulting in the plastic that held it in place beginning to melt. Fortunately the damage hadn’t progressed to the point where printing a replacement was necessary, so instead it was time to figure out how to remove the bearings without permanent damage. The trick that the manufacturer used was to peen the ends of the metal shafts that the bearings fit onto, requiring some Dremel action to convince them to come off.

After some careful modifications like this, the remnants of the old bearings came off and their replacements could go on. Due to the metal shaft modifications, it is now mostly the plastic caps on either end which grip the bearings, but it seems to work well enough. For $2 in bearings and some labor on [Mark]’s end, he managed to keep a perfectly good roller brush out of the landfill, and future bearing replacements should be much easier.

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Restoring A 1924 Frigidaire B-9 Refrigerator Back To Working Condition

January 26, 2026 by Maya Posch 13 Comments

Before the refrigerator became a normal part of any kitchen, those with enough money to throw around could get an icebox, which used melting ice to cool food and drinks in a second compartment. As refrigerators became available for sale in the 1920s, this created somewhat awkward transition models, like the 1924 Frigidaire B-9 that [David Allen] recently got offered for a restoration. This was part of the restoration of a 1926 house, which foresaw putting this venerable unit back into operation.

As [David] explains, this refrigerator was still in use until about 1970 when it broke down, and repairs proved tricky. Clearly, the fault wasn’t that severe as [David] got it working again after a number of small repairs and a lot of maintenance. The running unit with its basic elements can be seen purring away in the completion video, with the journey to get there covered in a video series starting with the first episode.

What’s fascinating is that during this aforementioned transition period, the vapor compression electric cooling system was an optional extra, meaning that the basic layout is still that of an icebox. Correspondingly, instead of ice in the ice compartment, you find the low-side float evaporator, with the basement section containing the condensing unit, motor, and compressor. The temperature sensor is also a miracle of simplicity, using bellows that respond to the temperature and thus volume of the evaporator coolant, which trigger a switch that turns on the compressor.

Despite a hundred years having passed since this refrigerator was constructed, at its core it works exactly the same as the unit we have in our kitchens today, albeit with higher efficiency, more electronics, and with the sulfur dioxide refrigerant replaced with something less toxic to us humans.

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Repair And Reverse-Engineering Of Nespresso Vertuo Next Coffee Machines

January 21, 2026 by Maya Posch 34 Comments

Well there’s your problem. (Credit: Mark Funeaux, YouTube)

Akin to the razor-and-blades model, capsule-based coffee machines are an endless grind of overpriced pods and cheaply made machines that you’re supposed to throw out and buy a new one of, just so that you don’t waste all the proprietary pods you still have at home. What this also means is a seemingly endless supply of free broken capsule coffee makers that might be repairable. This is roughly how [Mark Furneaux] got into the habit of obtaining various Nespresso VertuoLine machines for attempted repairs.

The VirtuoLine machines feature the capsule with a bar code printed on the bottom of the lip, requiring the capsule to be spun around so that it can be read by the optical reader. Upon successful reading, the code is passed to the MCU after which the brewing process is either commenced or cruelly halted if the code fails. Two of the Vertuo Next machines that [Mark] got had such capsule reading errors, leading to a full teardown of the first after the scanner board turned out to work fine.

Long story short and many hours of scrubbed footage later, one machine was apparently missing the lens assembly on top of the photo diode and IR LED, while the other simply had these lenses gunked up with spilled coffee. Of course, getting to this lens assembly still required a full machine teardown, making cleaning it an arduous task.

Unfortunately the machine that had the missing lens assembly turned out to have another fault which even after hours of debugging remained elusive, but at least there was one working coffee machine afterwards to make a cup of joe to make [Mark] feel slightly better about his life choices. As for why the lens assembly was missing, it’s quite possible that someone else tried to repair the original fault, didn’t find it, and reassembled the machine without the lens before passing the problem on to the next victim.

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The Shelly 2.5 Smart Relay Design Flaw Killing Capacitors

January 17, 2026 by Maya Posch 32 Comments

Part of any self-respecting Smart Home, smart relays are useful for switching and monitoring loads that do not plug into an outlet. This also makes them a lot more integrated, and thus, a long lifespan is very welcome. Unfortunately, the popular Shelly 2.5 smart relays seem to be having a bit of a design flaw as they’re dying in droves once their 2-year warranty period is up. The cause and repair are covered in a recent [VoltLog] video on YouTube.

As noted in the Shelly documentation for the device, it’s a very compact form factor device, with screw terminals, two relays, and three fairly large electrolytic capacitors sharing very little space with the rest of the components. The apparent flaw comes in the form of these capacitors failing, with the video showing that one 100 µF capacitor has a massively increased ESR, likely due to electrolyte venting. This results in the observed symptoms, such as WiFi connectivity issues and audible hissing, the latter of which is demonstrated in the video.

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A New Life For An Old Amplifier

January 14, 2026 by Jenny List 23 Comments

An audio amplifier was once a fairly simple analogue device, but in recent decades a typical home entertainment amplifier will have expanded to include many digital functions. When these break they are often proprietary and not easy to repair, as was the case with a broken Pioneer surround-sound device given to [Boz]. It sat on the shelf for a few years until he had the idea of a jukebox for his ripped CDs, and his returning it to life with a new main board is something to behold.

Internally it’s a surprisingly modular design, meaning that the front panel with its VFD display and driver were intact and working, as were the class AB amplifier and its power supply. He had the service manual so reverse engineering was straightforward, thus out came the main board in favor of a replacement. He took the original connectors and a few other components, then designed a PCB to take them and a Raspberry Pi Pico and DAC. With appropriate MMBASIC firmware it looks as though it was originally made this way, a sense heightened by a look at the motherboard inside (ignoring a couple of bodges).

We like seeing projects like this one which revive broken devices, and this one is particularly special quality wise. We’re more used to seeing it with gaming hardware though.