Teardown Of Casio Credit Card-Sized Radio

March 26, 2025 by Maya Posch 33 Comments

These days we don’t get too fussed about miniaturized electronics, not when you can put an entire processor and analog circuitry on a chip the size of a grain of sand. Things were quite different back in the 1980s, with the idea of a credit card-sized radio almost preposterous. This didn’t stop the engineers over at Casio from having a go at this and many other nutty ideas, with [Matt] from Techmoan having a go at taking one of these miniaturized marvels apart.

The Casio FM Stereo radio in happier days. (Credit: Techmoan, YouTube)

On the chopping block is the FM stereo device that was featured in a previous episode. Out of the four credit card-sized radios in that video, the one with the rechargeable battery (obviously) had ceased to work, so it was the obvious choice for a teardown. This mostly meant peeling off the glued-on top and bottom, after which the circuitry became visible.

In addition to the battery with a heavily corroded contact, the thin PCB contains a grand total of three ICs in addition to the analog circuitry. These were identified by [Spritetm] as an AM/FM tuner system IC (TA7792), an FM PLL MPX (TA7766AF) and a headphone amplifier (TA7767F), all of them manufactured by Toshiba.

Although [Matt] reckons this was a destructive teardown, we’re looking forward to the repair video where a fresh cell is soldered in and the case glued back together. Continue reading “Teardown Of Casio Credit Card-Sized Radio” →

Wire Recording Speaks Again

March 16, 2025 by Al Williams 14 Comments

If you think of old recording technology, you probably think of magnetic tape, either in some kind of cassette or, maybe, on reels. But there’s an even older technology that recorded voice on hair-thin stainless steel wire and [Mr. Carlson] happened upon a recorded reel of wire. Can he extract the audio from it? Of course! You can see and hear the results in the video below.

It didn’t hurt that he had several junk wire recorders handy, although he thought none were working. It was still a good place to start since the heads and the feed are unusual to wire recorders. Since the recorder needed a little work, we also got a nice teardown of that old device. The machine was missing belts, but some rubber bands filled in for a short-term fix.

The tape head has to move to keep the wire spooled properly, and even with no audio, it is fun to watch the mechanism spin both reels and move up and down. But after probing the internal pieces, it turns out there actually was some audio, it just wasn’t making it to the speakers.

The audio was noisy and not the best reproduction, but not bad for a broken recorder that is probably at least 80 years old. We hope he takes the time to fully fix the old beast later, but for now, he did manage to hear what was “on the wire,” even though that has a totally different meaning than it usually does.

It is difficult to recover wire recordings, just as it will be difficult to read modern media one day. If you want to dive deep into the technology, we can help with that, too.

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Inside A “Budget” Current Probe

March 16, 2025 by Al Williams 10 Comments

Current measurements are not as handy as voltage measurements. You typically need to either measure the voltage across something and do some math or break the circuit so a known resistor in your instrument develops a voltage your meter measures and converts for you. However, it is possible to get non-contact current probes. They are generally pricey, but [Kerry Wong] shows us one under $200 and, thus, budget compared to similar probes. Check out the review in the video below.

The OWON unit has three ranges: 4 A, 40 A, and 400 A. It claims a resolution of 10 mA and a bandwidth of 200 kHz. It requires a 9 V battery, which [Kerry] suspects won’t last very long given the rated power consumption number, although the measured draw was not as high as claimed. The specs aren’t great — this seems to be little more than a current probe meter with a connector for an oscilloscope, but if it meets your needs, that could be acceptable.

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Canon Arc Form Drive exploded. Credit: Markus Kohlpaintner

A Deep Dive Into Canon Autofocus Lenses

March 11, 2025 by Maya Posch 7 Comments

Although taken for granted these days, autofocus (AF) used to be a premium feature on film- and digital cameras, with [Markus Kohlpaintner] taking us through an exhaustive overview of Canon’s AF systems and how they work. On Canon cameras AF became a standard feature with the introduction of its EF lenses in 1987, which are found on its EOS SLR (single-lens reflex) series of professional and prosumer cameras.

Over the decades, Canon has used many different AF drive mechanisms within these lenses, all with their own pros and cons. The article goes through each of them, starting with the original Arc-Form Drive (AFD) and ending with the newest Voice Coil Motor (VCM), showing their internal construction. Of note are the USM (ultrasonic motor) types of AF systems that use a piezoelectric motor, the functioning of which using a traveling wave across the stator is also detailed, including the integrated feedback control system.

Ultimately the end user is mostly concerned with how well the AF works, of course. Here the biggest difference is probably whether manual adjustment is possible, with not all AF systems supporting full-time manual adjustment. With the newer AF systems this manual adjustment is now performed digitally rather than with a direct coupling. Although few people probably give AF much thought, it’s fascinating to see how much engineering went into these complex systems before even touching upon the algorithms that decide what to focus on in a scene.

Tiny Laptop Gets A New Case And An Unlocking

March 11, 2025 by Dan Maloney 21 Comments

Unless you’ve got an especially small lap, calling the Toshiba Libretto a laptop is a bit of a stretch. The diminutive computers from the mid-1990s had a lot of the usual laptop features, but in an especially compact and portable case that made them a great choice for anyone with an on-the-go lifestyle.

Fast-forward thirty years or so, and the remaining Librettos haven’t fared too well. Many of them have cases that crumble at the slightest touch, which is what led [polymatt] to undertake this meticulous case replacement. The effort started with a complete teardown; luckily, the lower aluminum-alloy shell was in fine shape, but the upper case parts were found to be almost too deteriorated to handle. Still, with a little patience and the judicious application of tape, [polymatt] was able to scan the case pieces on a flatbed scanner and import them into his CAD package. Great tip on the blue-tack for leveling the parts for accurate scanning, by the way.

After multiple rounds of printing and tweaking, [polymatt] had a case good enough to reassemble the Libretto. Unfortunately, the previous owner left an unwanted gift: a BIOS password. Disconnecting the CMOS battery didn’t reset it, but a little research told him that shorting a few pins on the parallel port on the machine’s dock should do the trick. It was a bit involved, requiring the design and subsequent bodging of a PCB to fit into the docking port connector, but in the end he was able to wake up a machine to all its Windows 95 glory. Better get patching.

In a time when laptops were more like lap-crushers, the Libretto was an amazing little machine, and thirty years on, they’re well worth saving from the scrap heap. Hats off to [polymatt] for the effort to save this beauty, and if he needs tips on reading data from any PCMCIA cards that may have come with it, we’ve got him covered.

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Red and gold bakelite Philco farm radio on a workbench

Hacking A Heavyweight Philco Radio

March 10, 2025 by Heidi Ulrich 6 Comments

There’s something magical about the clunk of a heavy 1950s portable radio – the solid thunk of Bakelite, the warm hum of tubes glowing to life. This is exactly why [Ken’s Lab] took on the restoration of a Philco 52-664, a portable AC/DC radio originally sold for $45 in 1953 (a small fortune back then!). Despite its beat-up exterior and faulty guts, [Ken] methodically restored it to working condition. His video details every crackling capacitor and crusty resistor he replaced, and it’s pure catnip for any hacker with a soft spot for analog tech. Does the name Philco ring a bell? Lately, we did cover the restoration of a 1958 Philco Predicta television.

What sets this radio hack apart? To begin with, [Ken] kept the restoration authentic, repurposing original capacitor cans and using era-appropriate materials – right down to boiling out old electrolytics in his wife’s discarded cooking pot. But, he went further. Lacking the space for modern components, [Ken] fabbed up a custom mounting solution from stiff styrofoam, fibreboard, and all-purpose glue. He even re-routed the B-wiring with creative terminal hacks. It’s a masterclass in patience, precision, and resourcefulness.

If this tickles your inner tinkerer, don’t miss out on the full video. It’s like stepping into a time machine.

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Transceiver Reveals Unusual Components

March 8, 2025 by Al Williams 22 Comments

[MSylvain59] likes to tear down old surplus, and in the video below, he takes apart a German transceiver known as a U-600M. From the outside, it looks like an unremarkable gray box, especially since it is supposed to work with a remote unit, so there’s very little on the outside other than connectors. Inside, though, there’s plenty to see and even a few surprises.

Inside is a neatly built RF circuit with obviously shielded compartments. In addition to a configurable power supply, the radio has modules that allow configuration to different frequencies. One of the odder components is a large metal cylinder marked MF450-1900. This appears to be a mechanical filter. There are also a number of unusual parts like dogbone capacitors and tons of trimmer capacitors.

The plug-in modules are especially dense and interesting. In particular, some of the boards are different from some of the others. It is an interesting design from a time predating broadband digital synthesis techniques.

While this transceiver is stuffed with parts, it probably performs quite well. However, transceivers can be simple. Even more so if you throw in an SDR chip.

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