repair

284 Articles

The scope, with new knobs and stickers on it, front panel renovated

Explosion-Scarred Scope Gets Plastic Surgery Hackerspace Style

January 2, 2024 by 9 Comments

Some equipment comes with a backstory so impressive, you can’t help but treat it with reverence. For instance, this Hantek scope’s front panel and knobs have melted when a battery pack went up in flames right next to it. Then, it got donated to the CADR hackerspace, who have in turn given us a scope front panel refurbishing master class (translated, original), demonstrating just how well a typical hackerspace is prepared for performing plastic surgery like this.

All of the tools they used are commonplace hackerspace stuff, and if you ever wanted to learn about a workflow for repairs like these, their wiki post is a model example, described from start to end. They show how they could use a lasercutter to iterate through figuring out mechanical dimensions of the labels, cutting the silhouette out of cardboard as they tweaked the offsets. Then, they designed and printed out the new front panel stickers, putting them through a generic laminator to make them last. An FDM printer helped with encoder and button knob test fits, with the final version knobs made using a resin printer.

Everything is open-source – FreeCAD knob designs, SVG stickers, and their CorelDraw sources are linked in the post. With the open-source nature, there’s plenty of room to improvement – for instance, you can easily put these SVGs through KiCad and then adorn your scope with panels made out of PCBs! With this visual overhaul, the Hantek DSO5102P in question has gained a whole lot more character. It’s a comprehensive build, and it’s just one of the many ways you can compensate for a damaged or missing shell – check out our comprehensive DIY shell guide to learn more, and when you get to designing the front panel, we’ve highlighted a few lessons on that too.

Saving A Scope From The Dumpster

September 24, 2023 by 9 Comments

If you read Hackaday, you probably get the title of [SunEstra’s] post: A Casual Date with the Dumpster. Many great hacking projects start with finding one man’s trash. This June, [SunEstra] rescued an old Tektronix 2465B oscilloscope, which appeared to be in good shape. Why we never find four-channel 400 MHz scopes in the dumpster is hard to explain, but we are still happy for him, if not a little jealous.

As you might expect, powering up the scope was a disappointment. Relays clicked. Lights flashed. But no display. Adjusting the grid bias on the CRT brought up the display, but it also brought up something else: an error message.

The scope was complaining of “test failure 05-40.” A look through the manual reveals that is “positive level too positive.” Huh. Too much of a good thing, we guess. The test checks the A5 board, so a visual inspection there was the first step.

Unsurprisingly, there were electrolytic capacitors leaking electrolyte. This is, apparently, a well-known problem with this scope. Replacing the electrolytics with some similar tantalum capacitors. In a few cases, the corrosion had eaten pads off the PCB, and some were damaged during the removal. It took a little ingenuity to connect the new parts on the board.

The result? A working scope. Maybe the scope will help repair the next thing that comes out of the dumpster. Sometimes, the best dumpster dives involve intercepting the gear before it hits the dumpster. We keep hoping to run into one of these on the curb (the linked post seems dead, but the video is still there).

Putting The Magic Smoke Back Into A Dodgy Spectrum Analyzer

September 12, 2023 by 3 Comments

The trouble with fixing electronics is that most devices are just black boxes — literally. Tear it down, look inside, but it usually doesn’t matter — all you see are black epoxy blobs, taunting you with the fact that one or more of them are dead with no external indication of the culprit.

Sometimes, though, you get lucky, as [FeedbackLoop] did with this Rigol spectrum analyzer fix. The instrument powered up and sort of worked, but the noise floor was unacceptably high. Even before opening it up, there was clearly a problem; in general, spectrum analyzers shouldn’t rattle. Upon teardown, it was clear that someone had been inside before and got reassembly wrong, with a loose fastener and some obviously shorted components to show for it. But while the scorched remains of components made a great place to start diagnosis, it doesn’t mean the fix was going to be easy.

Figuring out the values of the nuked components required a little detective work. The blast zone seemed to once hold a couple of resistors, a capacitor, a set of PIN diodes, and a couple of tiny inductors. Also nearby were a pair of chips, sadly with the markings lasered off. With some online snooping and a little bit of common sense, [FeedbackLoop] was able to come up with plausible values for most of these — even the chips, which turned out to be HMC221 RF switches.

Cleaning up the board was a bit of a chore — the shorted components left quite a crater in the board, which was filled with CA glue, and a bunch of missing pads. This called for some SMD soldering heroics, which sadly didn’t fix the noise problem. Replacing the two RF switches and the PIN diodes seemed to fix the problem, albeit at the cost of some loss. Sometimes, good enough is good enough.

This isn’t the first time [FeedbackLoop] has gotten lucky with choice test equipment in need of repairs — this memory module transplant on a scopemeter comes to mind.

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When Tail Lights Lose Touch With Reality

September 9, 2023 by 129 Comments

To study the history of the automobile is to also be a student of technological progress — as with each decade’s models come new innovations to make them better handling, more corrosion-resistant, faster, more efficient, or whatever the needs of the moment dictate. But sometimes that technological advancement goes awry and works against the motorist, making for a vehicle that’s substantially worse than what went before. [FordTechMakuloco] has a video with an example in a Ford pickup, which we believe deserves to be shared.

The problem with the vehicle was simple enough, indeed it’s one we’ve had in the past ourselves. Water got into a tail light, and corroded some connectors. The difference with this Ford though was that such a simple fault took out the whole car, and that the fix for a simple tail light cost $5600. The first was due to a vehicle-wide CAN bus going down due to the electrical short, and the second was due to the assembly containing an assortment of wiring and modules which couldn’t be replaced separately. These included some form of side-facing parking radar, a component unnecessary for operation of the light itself. Some relatively straightforward design and component supply decisions such as separating subsystems across multiple CAN busses, ensuring individual modules are separately available, and even designing connectors to face downwards and self-drain, could have fixed it, but the automaker chose instead to build in some planned obsolescence. Would you buy a Ford truck after seeing the video below the break?

We’ve written here before about how automotive design has taken this wrong path, and even advanced a manifesto as to how they might escape it. This Ford tail light seems to us an egregious example of electronics-as-the-new-rust rendering what should be a good vehicle into a badly designed piece of junk, and honestly it saddens us to see it. Oddly, there was once a time when a Ford truck was about as good as you could get.

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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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Impulse Buying A 3040 CNC Machine, What Could Go Wrong?

August 26, 2023 by 46 Comments

[joekutz] made an impulse purchase of a CNC machine. It was a 3040 CNC that looked reasonably complete and had an attractive price, what could possibly go wrong? As it happens, [joekutz] really didn’t know what he was in for. Sometimes the price is good, but you pay in other ways. But where some would see defeat, [joekutz] sees an opportunity to document the restoration.

Dial indicators are useful tools for measuring how straight some parts aren’t.

The 3040 are relatively cheap and simple CNC machines that have been available from a variety of overseas retailers for years. They have 30 cm by 40 cm beds (hence the name) and while there are many variations, they all work about the same. [joekutz] expected that getting his up and running and converted to open source would be a fun weekend project, but it ended up taking far longer than that. In fact, it turns out that the machine was damaged in surprising and unexpected ways.

[joekutz] has a series of videos demonstrating the process of diagnosing and repairing the various things wrong with this device. In the first video, he dismantles the machine and discusses the next steps. In the second video, he takes some time to repair some dial indicators that will be critical for measuring the various things wrong with the CNC parts. Video number three delves into finding out the horrible things wrong with the machine, and the fourth is where repairs begin, including bending shafts and sanding blocks back into service.

Those videos are embedded below, and while the machine isn’t quite restored yet, progress is promising. We’ve seen easy and effective upgrades for such CNC machines before, but if you happen to be in more of a repair and restore situation, give [joekutz]’s work a look because it might just save you some time and frustration.

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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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