Transistor Radio Repair, More Complex Than It Seems

September 7, 2023 by 48 Comments

The humble transistor radio is one of those consumer devices that stubbornly refuses to go away, but it’s fair to say that it’s not the mover and shaker in the world of electronics it might once have been. Thus it’s also not a staple of the repair bench anymore, where fixing a pocket radio might have been all in a day’s work decades ago now they’re a rare sight. [David Tipton] has a Philips radio from we’re guessing the later half of the 1960s which didn’t work, and we’re along for the ride as he takes us through its repair.

It’s an extremely conventional design of the era, with a self-oscillating mixer, 455 kHz IF amplifier, and class AB audio amplifier. The devices are a little archaic by today’s standards, with comically low-gain germanium transistors and passives from the Ark. Injecting a signal reveals that the various stages all work, but that mixer isn’t oscillating. A lot of fault-finding ensues, and perhaps with a little bit of embarrassment, he eventually discovers a blob of solder shorting a collector resistor to ground. All isn’t over though, for the volume pot is also kaput. Who knew that the track from a modern component could be transplanted into one from the 1960s?

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The McDonald’s Ice Cream Machine Saga And Calls For Right To Repair

August 30, 2023 by 45 Comments
The inside of a Taylor C709 ice cream machine, as seen from the back with the cover on the electronics removed. (Credit: iFixit)
The inside of a Taylor C709 ice cream machine, as seen from the back with the cover over the electronics removed. (Credit: iFixit)

Raising a likely somewhat contentious topic, iFixit and Public Knowledge have challenged the manufacturer behind McDonald’s ice cream machines to make them easy to diagnose and repair. This is a subject that’s probably familiar to anyone who is vaguely familiar with US news and the importance of ice cream at McDonald’s locations to the point that a live tracker was set up so that furtive customers can catch a glimpse at said tracker before finding themselves staring in dismay at an ‘Out of Order’ sign on one of these Taylor ice cream machines.

The story is more complex than just a machine being “broken”, however. The maintenance contracts are lucrative, the instruction manual is long, and the error codes are cryptic. When you add to that the complexity of cleaning and maintaining the machines, it’s tempting to just claim the machine is out of order. These Taylor machines (the C602 and the C709 from the iFixit video) are a bit more complex than your usual ice cream maker in that they also have a pasteurization element that’s supposed to keep already poured mix safe to use the next day.

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Off-Grid Radio Also Repairable Off-Grid

August 19, 2023 by 30 Comments

Low-power radios, often referred to in the amateur radio community as QRP radios, have experienced a resurgence in popularity lately. Blame it on certain parts of the hobby become more popular, like Parks on the Air (POTA) or Summits on the Air (SOTA). These are events where a radio operator operates off-grid at remote parks or mountaintops. These QRP rigs are a practical and portable way to make contacts. You would think that a five- or ten-watt rig running on batteries would be simple. Surprisingly, they can be enormously complex and expensive. That’s why [Dr. Daniel Marks] built the RFBitBanger, a QRP radio designed to not only be usable off-grid but to be built and maintained off-grid as well.

The radio accomplishes this goal by being built out of as many standard off-the-shelf components as possible. It eschews modern surface-mount components in favor of the much more accessible through-hole parts, including the ATMEGA328P at the center of the build. A PCB design is also available, but it can be built on perf board nearly as easily. The radio supports any mode a QRP operator might use, including CW, SSB, RTTY, and a new mode designed explicitly for this radio called SCAMP which is a low bandwidth, low SNR digital mode built into the Arduino-based firmware. It’s a single-band radio, but any band between 20 and 80 meters can be selected with pluggable filters.

As far as bomb-proof radios go, we can’t imagine a better way to live out an apocalypse than with a radio like this. As long as there’s a well-stocked parts drawer around, this radio could theoretically reach around the world without worrying about warranty claims, expensive parts, or even a company going out of business or not stocking parts for old radios anymore. There’s also more information about this build at the Open Research Institute for those interested. And, if you’re wondering how useful any radio could be using only five watts of transmitter power, take a look at this in-depth look at QRP radio operation.

Thanks to [Stephen Walters] for the tip.

Repairing A Home Injection Molding Machine

August 5, 2023 by 10 Comments

When [Michael] over at the Teaching Tech YouTube channel bought a hobby injection molding machine a long time ago, one of the plans he had with it was to use it for grinding up waste bits of PLA filament for injection molding. Since the machine was bought from a US shop and [Michael] is based in Australia it required some modifications to adapt it to the local 220+ VAC mains, followed by adding a PID temperature controller and a small compressor to provide the compressed air rather than from a large shop compressor.

Although [Michael] had discussed using the machine for PLA with the seller to confirm that this would work, a user error meant that the now defective unit had been sitting idly for many years, until recently.

Since the machine had been gathering dust and rust in the garage, fixing the machine up took a complete teardown to remove corrosion and resolve other issues. After this the original fault was identified, which turned out to be a shorted wire near the heater which had been turned up to a too high temperature, leading to the release of magic smoke and banishment of the machine to the Pit of Despair, AKA the shadowy depths of one’s garage.

In this first installment, [Michael] cleaned up the machine and restored it to a working state. In the next part injection molding will be attempted again, which should give some idea of the feasibility of turning scraps of PLA and failed 3D prints into smooth injection molded parts, assuming you have the CNC machine or patience to carve out the requisite molds, of course.

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Microsoft Now Offering Parts And Repair Guides For Xbox Controllers

August 2, 2023 by 11 Comments

We’re big fans of repairable hardware here at Hackaday, so much so that when we see a company embracing the idea that their products should actually be serviced rather than thrown in the trash, we like to call attention to it. Yes, that even includes when it’s Microsoft.

This community has had a mixed relationship with the Redmond software giant, to say the least. But we’ve still got to give them credit when they do something positive. Not only are they offering a full selection of replacement parts for both the standard and Elite Xbox controllers, they’ve also provided written instructions and step-by-step video guides on how to install your new parts.

For those of you who stopped playing console games when the controllers still only had two buttons, this might not seem like such a big deal. But considering a new Xbox Elite Wireless Controller will set you back a dizzying $180, it’s not hard to see why some folks would be excited about the possibility of swapping out the guts of the thing for $50.

Of course, these parts were already available from third party sellers, and iFixit naturally has repair guides for all the different flavors of Xbox controllers. Nothing about what Microsoft is doing here makes the Xbox controller fundamentally any easier to repair than it was previously. But the fact that the company isn’t treating their customers like adversaries is a step in the right direction.

Valve has been similarly open about the internals of the Steam Deck, though their presentation was a bit dramatic, and even Sony provided an official teardown video for the PS5. We’re not sure why these companies are willing to pull back the curtain when it comes to gaming hardware. Whatever the reason, we’re certainly not complaining.

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A Vintage Transistor Radio Gets A Repair

July 24, 2023 by 19 Comments

Here in 2023 the field of electronics covers a breathtaking variety of devices and applications, but if we were to go back in time far enough we’d enter an age in which computers were few and far between, and any automated control systems would have been electromechanical at best. Back in the 1950s the semiconductor industry was in relative infancy, and at the consumer end electronics were largely synonymous with radio. [Shango066] brings us a transistor radio from that era, a Jewel TR1 from about 1958, that despite its four-transistor simplicity to our eyes would have been a rare and expensive device when new.

As you’d expect, a transistor radio heading toward its 70th birthday requires a little care to return to its former glory, and while this one is very quiet it does at least work after a fashion. The video below the break is a long one that you might wish to watch at double speed, but it takes us through the now-rare skill of fault-finding and aligning an AM radio receiver. First up are a set of very tired electrolytic capacitors whose replacement restores the volume, and then it’s clear from the lack of stations that the set has a problem at the RF end. We’re treated to the full process of aligning a superhet receiver through the relatively forgiving low-frequency medium of a medium-wave radio. Along the way, he damages one of the IF transformers and has to replace it with a modern equivalent, which we would have concealed under the can from the original.

The video may be long, but it’s worth a look for the vintage parts if not for the quality of radio stations on the air today in California. For many readers, AM broadcast is becoming a thing of the past, so we’re not sure we’ll see this very often.

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A small B/W TV showing a Pong-like game being played on a Soviet-era game console

Soviet-Era Pong Console Is Easy To Repair

July 11, 2023 by 16 Comments

Many early home video game consoles were developed by American and Japanese companies: think Nintendo, Commodore, and Atari. But on the other side of the Iron Curtain, which was still very much in place in the 1980s, an entirely separate industry was built on names like Tesla and Elektronika. As a resident of the republic of Georgia, [Thomas] over at Workshop Nation has built up a sizeable collection of such Soviet-era hardware. A while back, he stumbled upon an Elektronika Video Sport 3, a 1990-vintage Pong-like video game console made in the USSR, and made a delightful video that shows him bringing it back to life.

A circuit board from an Elektronika game consoleLike its Western counterparts, the Video Sport 3 is built around a dedicated chip, in this case a K145IK17. This is a Soviet clone of the GI AY-3-8500 that powered nearly every TV Pong console in the West, allowing it to run several variations of Pong as well as a simple target shooting game. Interestingly, the Video Sport 3 also has a “test” mode in which it outputs a test signal to help you adjust your TV settings — quite useful in the days of analog CRTs. It also came with a comprehensive user manual, as well as full schematics to help you repair it in case anything breaks.

[Thomas]’s device didn’t immediately work, which is why he opened it up and tried to find any errors. The main board he found inside was a beautifully hand-made, single-layer board with around a dozen chips and lots of discrete components. Nothing seemed obviously broken, but [Thomas] decided to replace a few electrolytic capacitors as a precaution. This turned out to be enough to get the console working again — dodgy caps truly are a universal problem with older hardware.

A small Elektronika black-and-white TV that [Thomas] found earlier forms a perfect complement to the Video Sport 3. Together, they give us a glimpse into what a typical video game setup may have looked like in an early 1990s Soviet home. In fact, the Eastern Bloc supplied a reasonably wide selection of home computers, although not many people could actually buy them. Some truly bizarre machines were also produced for professional users.

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