Returning To An Obsolete Home Movie Format

September 4, 2025 by Jenny List 7 Comments

A few years ago, I bought an 8 mm home movie camera in a second hand store. I did a teardown on it here and pulled out for your pleasure those parts of it which I considered interesting. My vague plan was to put a Raspberry Pi in it, but instead it provided a gateway into the world of 8mm film technology. Since then I’ve recreated its Single 8 cartridge as a 3D printable model, produced a digital Super 8 cartridge, and had a movie camera with me at summer hacker camps.

When I tore down that Single 8 camera though, I don’t feel I did the subject justice. I concentrated on the lens, light metering, and viewfinder parts of the system, and didn’t bring you the shutter and film advance mechanism. That camera also lacked a couple of common 8 mm camera features; its light metering wasn’t through the lens, and its zoom lens was entirely manual. It’s time to dig out another 8 mm camera for a further teardown.

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Wire Photo Fax Teardown

August 24, 2025 by Al Williams 14 Comments

Fax machines had a moment in the sun, but they are actually much older than you might expect. Before the consumer-grade fax machines arrived, there was a thriving market for “wire photos” used by, for example, news organizations and the weather service. In the United States, the WEFax from Western Electric was fairly common and shows up on the surplus market. [Thomas] has an English unit, a Muirhead K-570B, that is very clearly not a consumer-oriented machine. His unit dates back to 1983, but it reminds us of many older designs. Check out his teardown in the video below.

The phone line connection on this device is a pair of banana jacks! There are even jacks for an external meter. Inside, the device is about what you’d expect for a 1983 build. PCBs with bare tinned conductors and lots of through-hole parts.

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The Oscilloscope From 1943

August 23, 2025 by Al Williams 5 Comments

[Thomas] comes up with some unusual gear. In his latest teardown and repair video, he has a vintage 1943 Danish oscilloscope, a Radiometer OSG32 on the bench. It isn’t lightweight, and it certainly looks its age with a vintage cracked finish on the case. You can check out the tubes and high-voltage circuitry in the video below.

If you’ve only seen the inside of a modern scope, you’ll want to check this out with giant condensers (capacitors) and a slew of tubes. We love seeing the workmanship on these old chassis.

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Silent Speak And Spell Gets Its Voice Back

August 18, 2025 by Al Williams 4 Comments

While talking computers are old hat today, in 1978, a talking toy like the Speak and Spell was the height of novel tech. [Kevin] found a vintage one, but it didn’t work. It looked like someone had plugged in the wrong power adapter, leading to, undoubtedly, one or more unhappy children. There was some damage that suggests someone had already tried to repair it, but without success.

In addition to effecting the repair, [Kevin] took lots of pictures, so if you ever wanted to peek inside one of these, this is your chance. The case had no screws, just clips, although apparently some of the newer models did have some screws.

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Teardown Of A Persil Smartwash Smart Laundry Detergent Ball

August 7, 2025 by Maya Posch 37 Comments

How to make doing laundry more smart, depending on your perspective. (Credit: Zerobrain, YouTube)

Ever since the invention of washing machines, the process of doing laundry has become rather straightforward. Simply toss the dirty laundry into the machine, fill up the detergent, and let the preset program handle the rest. This of course has not prevented companies from coming up with ways to add more complexity to doing laundry, with Henkel’s Smartwash technology the latest example, as demonstrated by German YouTube channel [ZeroBrain] with a complete teardown.

Henkel is the owner of detergent brands like Persil and Somat, with the Smartwash ball supposedly offering ‘smart’ dosing of detergent for washing machines, with naturally a smartphone app with intrusive localization to personalize the laundry experience. Sadly the video is only in German, but the language of teardowns is universal.

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Buying Large LiFePO4 Batteries: How Cheap Is Too Cheap?

August 7, 2025 by Maya Posch 42 Comments

It’s a well-known factoid that batteries keep getting cheaper while capacity increases. That said, as with any market that is full of people who are hunting for that ‘great deal’, there are also many shady sellers who will happily sell you a product that could be very dangerous. Especially in the case of large LiFePO₄ (LFP) batteries, considering the sheer amount of energy they can contain. Recently [Will Prowse] nabbed such a $125, 100 Ah battery off Amazon that carries no recognizable manufacturer or brand name.

If this battery works well, it could be an amazing deal for off-grid and solar-powered applications. Running a battery of tests on the battery, [Will] found that the unit’s BMS featured no over-current protection, happily surging to 400 A, with only over-temperature protection keeping it from melting down during a discharge scenario. Interestingly, under-temperature charge protection also worked on the unit.

After a (safe) teardown of the battery the real discoveries began, with a row of missing cells, the other cells being re-sleeved and thus likely salvaged or rejects. Fascinatingly, another YouTuber did a similar test and found that their (even cheaper) unit was of a much lower capacity (88.9 Ah) than [Will]’s with 98 Ah and featured a completely different BMS to boot. Their unit did however feature something of a brand name, though it’s much more likely that these are all just generic LFP batteries that get re-branded by resellers.

What this means is that these LFP batteries may be cheap, but they come with cells that are likely to be of questionable quality, featuring a BMS that plays it fast and loose with safety. Although [Will] doesn’t outright say that you shouldn’t use these batteries, he does recommend that you install a fuse on it to provide some semblance of over-current protection. Keeping a fire extinguisher at hand might also be a good idea.

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Not Repairing An Old Tape Recorder

July 24, 2025 by Al Williams 13 Comments

When you think of a tape recorder, you might think of a cassette tape. However, [Michael Simpson] has an old Star-Lite small reel-to-reel tape machine. It isn’t a repair so much as a rework to make it work better. These cheap machines were never the best, although a $19 tape player back then was a luxury.

Part of the problem is that the design of the tape player wasn’t all that good to begin with. The motor runs off two C cells in parallel. When these were new in the 1960s, that would have meant conventional carbon-zinc batteries, so the voltage would have varied wildly. That didn’t matter, though, because the drive was directly to the tape reel, so the speed also varied based on how much tape was left on the reel.

The amplifier has four transistors. [Michael] decided to replace the capacitors on the unit. He noticed, too, that the volume control is in line with the microphone when recording, so even though the recording was supposedly in need of repair, it turned out to be simply a case of the volume control being turned down. Pretty impressive for a six-decade-old piece of consumer electronics.

The capacitor change-out was simple enough. Some cleaning and lubing was also in order. Did it help? You’ll have to listen and decide for yourself.

So, no real repair was in the works, but it is an interesting look back at an iconic piece of consumer tech. Tape recorders like this were an early form of social media. No kidding. If you’d rather not buy a tape recorder, you could roll your own.

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