Serious Repair Work On The Amiga 600

February 5, 2020 by Lewin Day 4 Comments

The Amiga will be forever loved for bringing serious multimedia capabilities to the home computer market. However, these machines are now showing their age, and keeping them running can take a bit of work. [Drygol] isn’t one to shy away from the task, however, and set about repairing a few Amiga 600s that came his way.

First up on the docket is replacing the many electrolytic capacitors that tend to leak over the years. They can cause corrosion, destroying traces and other components, as well as failing themselves. [Drygol] is an old hand at this now, whipping out the hot air station and some copper shielding to protect delicate connectors from melting. A simple recap was enough to get one machine up and running, but the other was more recalcitrant. When swapping a dud CPU out, a pad was destroyed on the PCB. This necessitated some careful tracing, followed by a drill hole through the PCB to allow a bodge wire to run the signal from the other side of the board.

There’s also plenty of upgrades to be done; S-Video outputs instead of the crummy old RF modulator, and special interrupt switches that help when cracking games and doing assembly programming. Thanks to a rich aftermarket and vivid community, researching and performing mods is easy thanks to writeups and parts available online.

It’s a great example of the basic techniques one must master to keep old hardware on the boil. Learn to recap, refit, and hunt for problems, and you’ll be well on your way to maintaining your retro fleet for years to come. We’ve seen [Drygol]’s work before too – this vampiric A500 is a particular treat!

Lathe And 3D Printer Help Repair Buried Buttons

February 3, 2020 by Tom Nardi 24 Comments

Usually corroded buttons on a piece of electronic equipment wouldn’t be that big a deal to repair, but as [Haris Andrianakis] recently found out, things can get a little tricky when they are sealed inside a device meant to operate in a marine environment. Figuring out how to get into the case to clean the buttons up is only half the battle, when you’re done you still need to close it back well enough that the elements can’t get in.

The device in question is a tachometer intended for a Yamaha outboard motor, and the buttons are sealed between the guage’s face and the compartment in the rear that holds the electronics. Pulling the guts out of the back was no problem, but that didn’t get [Haris] any closer to the defective buttons. In light of the cylindrical design of the gauge, he decided to liberate the front panel from the rest of the unit with his lathe.

Removing the face was a delicate operation, to put it mildly. The first challenge was getting the device mounted securely in the chuck, but then the cutting had to be done very carefully so as not to damage the housing. Once he cut through the side far enough to get the face off, the actual repair of the buttons was fairly straightforward. But how to get it back together?

After a few missteps, [Haris] finally found a solution that have him the results he was looking for. He 3D printed a ring that fit the front of the gauge tightly, hot glued it into place, and used it as a mould to pour in black epoxy resin. Once the epoxy had cured, the mould was cut off and the gauge went back on the lathe so he could trim away the excess. He had to do some hand sanding and filing to smooth out the bezel, but overall the end result looks very close to factory.

We get it, there’s a lot to consider when you add a lathe to your workshop. But hacks like these are wonderful reminders of how many tricks these versatile machines are really capable of.

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Tidy Board Rework Uses Flex PCBs, No Wires

December 17, 2019 by Donald Papp 26 Comments

PCB rework for the purpose of fixing unfortunate design problems tends to involve certain things: thin wires (probably blue) to taped or glued down components, and maybe some areas of scraped-off soldermask. What are not usually involved are flexible PCBs, but [Paul Bryson] shows us exactly how flex PCBs can be used to pull off tricky rework tasks.

It all started when [Paul] had a run of expensive PCBs with a repeated error; a design mistake that occurred in several places in the board. Fixing with a bunch of flying wires leading to some glued-on components just wasn’t his idea of tidy. A more attractive fix would be to make a small PCB that could be soldered in place of several of the ICs on the board, but this idea had a few problems: the space available into which to cram a fix wasn’t always the same, and the footprints of the ICs to be replaced were too small to accommodate a PCB with castellated mounting holes as pads anyway.

It’s about then that he got a visit from the Good Idea Fairy, recalling that fab houses have recently offered “flex” PCBs at a reasonable cost. By mounting the replacement parts on a flex PCB, the board-level connection could reside on the other end of an extension. Solder one end directly to the board, and the whole flexible thing could be bent around or under on a case-by-case basis, and secured in whatever way made sense. Soldering the pads of the flex board to the pads on the PCB was a bit tricky, but easy enough to pull off reliably with a bit of practice. A bonus was that the flex PCB is transparent, so solder bridges are easy to spot. He even mocked up a solution for QFP packages that allows easy pin access.

Flex PCBs being available to hobbyists and individuals brings out fresh ideas and new twists on old ones, which is why we held a Flexible PCB Design Contest earlier this year. Repairs were definitely represented as applications, but not to the extent that [Paul] has shown. Nice work!

Rescue An Expensive Servo With Some Reverse Engineering

December 11, 2019 by Donald Papp 9 Comments

[Andrew] had a servo damaged by someone connecting the power supply to the wrong pins (whoops) which fried the microcontroller and a logic level shifter. With a bit of reverse engineering, he successfully restored basic servo functionality by writing some new code. The new code implements only basic features, but that’s enough to save the device from the junk bin.

FAULHABER 2232DBHHO ring any bells? Google came up empty.

Why bother reverse engineering a servo? Well, if dollars are reasons then there are many for saving a HerkuleX DRS-0602 from the junk heap; they cost around 320 USD before shipping. Another reason to try is that the microcontroller turned out to be an AVR XMega, which gave [Andrew] confidence in writing some new code.

If you want to understand more about how these servos work, [Andrew] provides good photos of the insides and identifies the major components and their connections and functions. There are some mysteries (such as details of the motor and embedded encoder, which are FAULHABER 2232DBHHO) but [Andrew] figured out enough to write some basic code to allow the servo to work as a standard servo with a UART interface.

Sometimes curiosity drives reverse engineering and repair efforts, sometimes it’s cost, and sometimes it’s both. A $320 servo is certainly worth trying to save, and so are huge observatory telescopes with obsolete servo amps.

Restoring A Dead Commodore 128DCR

December 4, 2019 by Tom Nardi 11 Comments

Another day, another retro computer lovingly restored to like-new condition by [Drygol]. This time, the subject of his attention is a Commodore 128DCR that earned every bit of the “For Parts, Not Working” condition it was listed under. From a spider infestation to a cracked power supply PCB, this computer was in quite a state. But in the end he got the three decade old machine back in working condition and even managed to teach it a few new tricks along the way.

Obviously the shattered PSU was the most pressing issue with the Commodore. Interestingly, the machine still had its warranty seal in place on the back, so whatever happened to this PSU seems to have occurred without human intervention.

Rather than just replacing the PSU, [Drygol] first pieced the board back together with the help of cyanoacrylate glue, and then coated the top with an epoxy resin to give it some mechanical strength. On the back side the traces were either repaired or replaced entirely with jumper wires where the damage was too severe.

With the PSU repaired and tested, he moved on to cleaning the computer’s main board and whitening all the plastic external components. Even the individual keycaps took a bath to get them looking like new again. This put the computer in about as close to like-new condition as it could get.

But why stop there? He next installed the JiffyDOS modification to improve system performance, and wired in an adapter that lets the computer output a crisp 80 columns over S-Video. It’s safe to say this particular Commodore is in better shape now than it was when it rolled off the assembly line.

While an impressive enough final result, this is still fairly tame for [Drygol]. If you want to see a real challenge, take a look at the insane amount of work that went into recreating this smashed Atari 800XL case.

Considering The Originality Question

November 9, 2019 by Jenny List 37 Comments

Many Hackaday readers have an interest in older technologies, and from antique motorcycles to tube radios to retrocomputers, you own, conserve and restore them. Sometimes you do so using new parts because the originals are either unavailable or downright awful, but as you do so are you really restoring the item or creating a composite fake without the soul of the original? It’s a question the railway film and documentary maker [Chris Eden-Green] considers with respect to steam locomotives, and as a topic for debate we think it has an interest to a much wider community concerned with older tech.

Along the way the film serves as a fascinating insight for the non railway cognoscenti into the overhaul schedule for a working steam locomotive, for which the mainline railways had huge workshops but which presents a much more significant challenge to a small preserved railway. We wrote a year or two ago about the world’s first preserved railway, the Welsh Tal-y-Llyn narrow gauge line, and as an example the surprise in the video below is just how little original metal was left in its two earliest locomotives after their rebuilding in the 1950s.

The film should provoke some thought and debate among rail enthusiasts, and no doubt among Hackaday readers too. We’re inclined to agree with his conclusion that the machines were made to run rather than gather dust in a museum, and there is no harm in a majorly-restored or even replica locomotive. After all, just as a retrocomputer is as much distinguished by the software it runs, riding a steam train is far more a case of sights and smells than it is of knowing exactly which metal makes up the locomotive.

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Restoring A Rusty Rebar Cutter

October 27, 2019 by Dan Maloney 16 Comments

We’ve all probably come across hunks of junk that used to be tools, long-neglected and chemically welded into a useless mass of solid rust. Such items are available for a pittance at the local flea market, or more likely found in an old barn or rotting on a junk pile. They appear to be far beyond salvage, but with the proper application of elbow grease and penetrating lubricants, even a nasty old seized-up rebar cutter can live again.

We honestly almost passed up on the video below when it came across our feed. After all, a rebar cutter is a dead-simple device, and half the fun of restoration videos like those made by [my mechanics] is seeing all the parts removed, restored, and replaced. But it ended up being far more interesting than we expected, and far more challenging too.

The cutter was missing its original handle and looked for all the world like it had been cast from a solid piece of iron oxide. [my mechanics] was able to get the main pivot bolts free with a combination of leverage, liberal application of penetrating oil, drilling, and the gentle persuasion of a hydraulic press.

These efforts proved destructive to both bolts, so new ones were made on the lathe, as were a number of other parts beyond saving. New cutters were fabricated from tool steel and a new handle was built; before anyone comments on anyone’s welding skills, please read [Jenny]’s recent article on the subject.

The finished product is strikingly dissimilar to the starting lump of oxidized junk, so there’s going to to be some debate in calling this a “restoration” in the classical sense. The end result of a [my mechanics] video is invariably a tool or piece of gear that looks far better than it did the day it was made, and any one of them would get a place of honor on our shelf. That said, he’d probably be swiftly shown the door if he worked at the Smithsonian.

Whatever you want to call these sort of videos, there are tons of them out there. We’ve featured a few examples of the genre, from the loving rehabilitation of classic Matchbox cars to rebuilding an antique saw set. They’re enough to make us start trolling garage sales. Or scrap yards.

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