PCB Solder Pad Repair & Cleanup

What do you do when your motherboard is covered in electrolytic grime, has damaged pads and traces that are falling apart? You call [RetroGameModz] to work their magic with epoxy and solder.

While this video is a bit old, involved repair videos never go out of style. What makes this video really special is that it breaks from the common trend of “watch me solder in silence” (or it’s close cousin, “watch me solder to loud music”). Instead, [RetroGameModz] walks you through what they’re doing, step by step in their repair of a motherboard. And boy do they have their work cut out for them: the motherboard they’re working on has definitely seen better days. Specifically, it was better before corrosion from a leaking electrolytic capacitor and the well-meaning touch of its owner.

After a quick review of the damage, all of the components are removed from the battle zone. Then the cleaning begins, taking special precautions not to rip pads up. After everything’s cleaned up, things get really interesting. [RetroGameModz] starts to make their own pads from raw copper using the old pads as templates to replace the missing ones on the motherboard. After a bit of epoxy, it’s hard to tell that the pads were handmade, they fit in so well.

This epoxy trick is also used to deal with some heavily damaged traces, cool! During this repair, [RetroGameModz] used an epoxy that is heat resistant up to 315°C for 60 seconds. If you ever find any kind of epoxy on the market that is specified to be heat resistant up to more than 315°C, [RetroGameModz] would be quite happy if you could leave some info in the comment section, as they’ve found high-temperature epoxies quite difficult to source.

This goes to show that some repairs really should be done by professionals. [RetroGameModz] surely agrees, stating that “If you are not a repair technician and your motherboard has stopped working, it would be in the best of your own interest not to attempt a repair that you really cannot handle.” Good advice. But, we can never resist trying to fix things ourselves before handing things off to the more experienced. Call it a vice, or a virtue; we’ll call it fun.

What do you think? Are there some repairs you rely on technicians for? Or do you fix everything yourself? Let us know in the comments.

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Hacked Sea Scooter Lives Another Day

The Seadoo GTI Sea Scooter is a simple conveyance, consisting of a DC motor and a big prop in a waterproof casing. By grabbing on and firing the motor, it can be used to propel oneself underwater. However, [ReSearchITEng] had problems with their unit, and did what hackers do best – cracked it open to solve the problem.

Investigation seemed to suggest there were issues with the logic of the motor controller. The original circuit had a single FET, potentially controlled through PWM.  The user interfaced with the controller through a reed switch, which operates magnetically. Using reed switches is very common in these applications as it is a cheap, effective way to make a waterproof switch.

It was decided to simplify things – the original FET was replaced with a higher-rated replacement, and it was switched hard on and off directly by the original reed switch. The logic circuitry was bypassed by cutting traces on the original board. [ReSearchITEng] also goes to the trouble of highlighting potential pitfalls of the repair – if the proper care isn’t taken during the reassembly, the water seals may leak and damage the electronics inside.

Overall it’s a solid repair that could be tackled by any experienced wielder of a soldering iron, and it keeps good hardware out of the landfill. For another take on a modified DC motor controller, check out the scooter project of yours truly.

 

Restoring a Retro 747 Control Display Unit

Anyone who’s into retro aviation gear falls in love with those mysterious displays, dials, keypads, banks of knife switches. There’s a lot of sexy in those devices, built with high standards in a time when a lot of it was assembled by hand.

[Jeremy Gilbert] bought a 747-200’s Control Display Unit (CDU)– the interface with the late ’70s in-flight computer–and is bringing it back to life in a Hackaday.io project. His goal is to get it to light up and operate just as if it were installed in a 747.

Of particular interest is the display, which turned out to consist of a series of 5×7 matrices (seen on the right) controlled by chips no one uses any more. However, [Jeremy] found a blog post where someone had hacked out Arduino code for a cousin of the chip, saving him a lot of time. However, he’s got a lot more sleuthing yet to do.

If you’re into retro displays, we’ve mentioned a number of good ones, including the legendary Apollo DSKY and an awesome retrocomputer.

 

 

 

Unlikely Cascade of Failures Leads to Microwave’s Demise

Surely a blown light bulb can’t kill a microwave oven, right? You might not expect it to, but that was indeed the root cause of a problem that [mikeselecticstuff] recently investigated; the cascade of failures is instructive to say the least.

While the microwave that made its way to [mike]’s bench wasn’t exactly engineered to fail, it surely was not designed to succeed. We won’t spoil the surprise, but suffice it to say that his hopes for a quick repair after the owner reported a bang before it died were dashed by an arc across the interior light bulb that put a pulse of mains voltage in places it didn’t belong. That the cascade of failures killed the appliance is a testament to how designing to a price point limits how thoroughly devices can be tested before production runs in the millions are stuffed into containers for trips to overseas markets.

Even though [mike] made his best effort to adhere to the Repair Manifesto, the end result was a scrapped microwave. It wasn’t a total loss given the interesting parts inside, but a disappointment nonetheless unless it forces us to keep in mind edge-case failure modes in our designs.

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Hand-Wound Brushless Motors Revive Grounded Quad

You’re happily FPVing through the wild blue yonder, dodging and jinking through the obstacles of your favorite quadcopter racing course. You get a shade too close to a branch and suddenly the picture in your goggles gets the shakes and your bird hits the dirt. Then you smell the smoke and you know what happened – a broken blade put a motor off-balance and burned out a winding in the stator.

What to do? A sensible pilot might send the quad to the healing bench for a motor replacement. But [BRADtheRipper] prefers to take the opportunity to rewind his burned-out brushless motors by hand, despite the fact that new ones costs all of five bucks. There’s some madness to his method, which he demonstrates in the video below, but there’s also some justification for the effort. [Brad]’s coil transplant recipient, a 2205 racing motor, was originally wound with doubled 28AWG magnet wire of unknown provenance. He chose to rewind it with high-quality 25AWG enameled wire, giving almost the same ampacity in a single, easier to handle and less fragile conductor. Plus, by varying the number of turns on each pole of the stator, he’s able to alter the motor’s performance.

In all, there are a bunch of nice tricks in here to file away for a rainy day. If you need to get up to speed on BLDC motor basics, check out this primer. Or you may just want to start 3D printing your own BLDC motors.

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JB Weld Fixes Cracked Cylinder Heads

There are persistent rumors that the main ingredient in JB Weld is magic. This two-part epoxy that you would normally find on a shelf next to your basic 5-minute epoxy, Titebond, various cyanoacrylates, and Gorilla glue is somehow different. Stories of ‘some guy’ in the Yukon using JB Weld on a cracked engine block abound. These stories are of course met with skepticism.

Now, finally, we have evidence you can use JB Weld to fix an engine. [Project Farm] over on YouTube gave it the ultimate test: he took the cylinder head off a lawnmower, took a grinder to the head, and patched the hole with JB Weld. The head had good compression, and the engine actually ran for 20 minutes before the test was concluded.

If this were a test of a field repair, it would be a test of an extremely crappy field repair. [Project Farm] made no attempt to ensure the piston didn’t make contact with the blob of JB Weld, and in fact, there was some slight knocking from the piston tapping against a blob of epoxy. Still, this repair worked.

While this serves as proof of the feasibility of repairing an engine block with JB Weld, there is one ultimate test of JB Weld epoxy: build an engine out of it. For years, I’ve been casting my leftover JB Weld into a small square plastic container. In a few more years, I’ll have a block of JB Weld ‘stock’, large enough to machine the parts for a small (.049 cc) glow engine, like what you would find in ye olde tymie model planes and cars. Will it work? I have no idea, but now I can’t wait to find out.

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The Princess and the HDD: Poor Design Choices

You’ll all remember my grand adventure in acquiring a photocopier. Well, it’s been a rollercoaster, I tell ya. While I still haven’t found a modification worthy enough to attempt, I have become increasingly frustrated. From time to time, I like to invite my friends and family over for dinner, and conversation naturally turns to things like the art on the walls, the fish in the aquarium, or perhaps the photocopier in the living room. Now, I dearly love to share my passions with others, so it’s pretty darned disappointing when I go to fire off a few copies only to have the machine fail to boot! It was time to tackle this problem once and for all.

When powered up, the photocopier would sit at a “Please Wait…” screen for a very long time, before eventually coughing up an error code — SC990 — and an instruction to call for service. A bunch of other messages would flash up as well; Address Book Data Error, Hard Drive Data Error, and so on. In the end I realized they all centered around data storage.

Pictured: the author, in his happy place, at peace with the copier.

Now, I’d already tried diving into the service menu once before, and selected the option to format the hard drive. That had led to the problem disappearing for a short period, but now it was back. No amount of mashing away at the keypad would work this time. The format commands simply returned “Failed” every time. What to do next? You guessed it, it was time for a teardown!

Thankfully, photocopiers are designed for easy servicing — someone’s paying for all those service calls. A few screws and large panels were simply popping off with ease; completely the opposite of working on cars. Spotting the hard drive was easy, it looked like some sort of laptop IDE unit. With only SATA laptops around the house to salvage parts from, I wasn’t able to come up with something to swap in.

A bit of research (and reading the label) taught me that the drive was a Toshiba MK2023GAS/HDD2187. Replacements were available on eBay, but if I waited two weeks I’d probably be wrist deep in some other abandoned equipment. It had to be sorted on the night. In the words of [AvE], if you can’t fix it… well, you know how it goes. I yanked the drive and, lo and behold – the copier booted straight up! Just to be sure I wasn’t hallucinating, I churned out a few copies, and other than the continued jamming on all-black pages, everything was fine. Literally all it took to get the copier to boot was to remove the ailing drive. Suffice to say, I was kind of dumbfounded.

The hard drive a.k.a. the villain of the piece.

I’m happy to chalk up the win, but I have to draw issue with Ricoh’s design here. The copier is clearly capable of operating perfectly well without a hard drive. It will give up its document server and address book abilities, but it will still make copies and print without a problem.

Yet, when the copier’s drive fails, the unit fails completely and refuses to work. This necessitates a service call for the average user to get anything at all happening again — causing much lost work and productivity. A better design in my eyes would have the copier notify users of the lost functionality due to the failed drive and the need to call service, but let them copy! Any IT administrator will know the value of a bodged work around that keeps the company limping along for the day versus having a room of forty agitated workers with nothing to do. It’s a shame Ricoh chose to have the photocopier shut down completely rather than valiantly fight on.

Feel free to chime in with your own stories of minor failures that caused total shutdowns in the comments. Video below the break.

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