Broken Plastic? No Problem!

March 17, 2017 by Jenny List 34 Comments

When a computer case has survived several decades from being a new toy through being an unloved relic to being rediscovered and finding its way into the hands of an enthusiast, it is inevitable that it will have picked up some damage along the way. It will be scuffed, maybe cracked, and often broken. If it has faced the ordeal of an international courier after an eBay sale then the likelihood of a break increases significantly.

If you receive a vintage computer in the post and find it cracked or broken, never fear. [Drygol] has a solution, a guide to plastic welding with a soldering iron.

After a thorough cleaning, the technique is to hold the sides of the break together, run the iron along it to melt the plastic together, and scrape the overflowed plastic back into the resulting trench before it solidifies. With careful sanding, a spot of polyester putty, and some spray paint, the broken case can be returned to new condition.

There is a video showing the process, in this case repairing a crack on a Commodore 64 case.

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Das Fix

March 9, 2017 by Jenny List 35 Comments

There was a time when the desktop peripherals such as your keyboard and mouse were expensive items that you hung on to and cared for. But several decades of PC commoditization and ever-cheaper manufacturing have rendered each of them to an almost throwaway level, they are so cheap that when one breaks you can simply reach for another without thought.

This is not to say that there is no longer a space for a more costly specialist keyboard. You’ll find enthusiasts still clinging to their treasured vintage IBM Model Ms and Model Fs, or typing on a range of competing high end ‘boards. You might say that a cheap keyboard is pretty high quality these days, but for some people only the feel of a quality switch will do.

[Mac2612] was given a particularly nice example of this class of peripheral, a Das Keyboard 4C complete with trademark missing key decals. There was a snag though, it has suffered a spill at some time in its life, and would issue random keypresses which rendered it useless. His marathon investigation and repair of the fault makes for an interesting read, and gives us some insight into why these keyboards cost the extra money.

“To my dismay, I quickly realized that this was probably an unnecessary endeavor…”

At first it seemed as though corrosion on the board might be the issue, so he gave it a clean with IPA. All to no avail, and so began a succession of further dismantlings and cleanups which culminated in the desoldering of all the key switches. This lengthy task shows us in detail the construction of a high-end ‘board, but sadly it didn’t reveal the fault, and phantom keypresses kept appearing.

Following the board traces back to the microcontroller, he eventually found that moisture had corroded the end of a 10K surface mount resistor, leaving it with a resistance in the MOhms. Since it was a pulldown for one of the keyboard rows, he’d found the source of the problem. Having spent a long time fault-finding a board with an SMD part with a mechanical failure, we feel his pain.

Replacing the SMD parts and reassembly gave him a rather sweet keyboard, albeit for a lot of work.

This is the first Das Keyboard teardown we’ve brought you, but not the first keyboard hack. There are the people remanufacturing the Model F, for example, or the most minimalist keyboard possible.

[Thanks Graham Heath, via /r/MechanicalKeyboards]

Fixing Fake FTDIs

March 7, 2017 by Brian Benchoff 129 Comments

If you know where to go on the Internet, you can pick up an FTDI USB to Serial adapter for one dollar and sixty-seven cents, with free shipping worldwide. The chip on this board is an FTDI FT232RL, and costs about two dollars in quantity. This means the chips on the cheap adapters are counterfeit. While you can buy a USB to serial adapter with a legitimate chip, [Syonyk] found a cheaper solution: buy the counterfeit adapters, a few genuine chips, and rework the PCB. It’s brilliant, and an excellent display of desoldering prowess.

Why is [Syonyk] replacing non-genuine chips with the real FTDI? The best reason is FTDIgate Mk. 1, where the official FTDI driver for Windows detected non-genuine chips and set the USB PID to zero. This bricked a whole bunch of devices, and was generally regarded as a bad move. FTDIgate Mk. 2 was a variation on a theme where the FTDI driver would inject garbage data into a circuit if a non-genuine part was found. This could also brick devices. Notwithstanding driver issues, the best reason for swapping out fake chips for real ones is the performance at higher bit rates; [Syonyk] is doing work at 3 Mbps, and the fake chips just don’t work that fast.

To replace the counterfeit chip, [Syonyk] covered the pins in a nice big glob of solder, carefully heated both sides of the chip, and slid the offending chip off when everything was molten. A bit of solder braid, and the board was ready for the genuine chip.

With the new chip, the cheap USB to serial adapter board works perfectly, although anyone attempting to duplicate these efforts might want to look into replacing the USB mini port with a USB micro port.

What Does A Hacker Do With A Photocopier?

February 24, 2017 by Lewin Day 130 Comments

The year is 2016. Driving home from a day’s work in the engineering office, I am greeted with a sight familiar to any suburban dwelling Australian — hard rubbish. It’s a time when local councils arrange a pickup service for anything large you don’t want anymore — think sofas, old computers, televisions, and the like. It’s a great way to make any residential area temporarily look like a garbage dump, but there are often diamonds in the rough. That day, I found mine: the Ricoh Aficio 2027 photocopier.

It had spent its days in a local primary school, and had survived fairly well. It looked largely intact with no obvious major damage, and still had its plug attached. Now I needed to get it home. This is where the problems began.

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Repairing Crystal Earpieces

February 7, 2017 by Al Williams 11 Comments

If you make crystal radios, you’ve probably got a few crystal earpieces. The name similarity is a bit coincidental. The crystal in a crystal radio was a rectifier (most often, these days, a germanium diode, which is, a type of crystal). The crystal in a crystal earpiece is a piezoelectric sound transducer.

Back in the 1960s, these were fairly common in cheap transistor radios and hearing aids. Their sound fidelity isn’t very good, but they are very sensitive and have a fairly high impedance, and that’s why they are good for crystal radios.

[Steve1001] had a few of these inexpensive earpieces that either didn’t work or had low sound output. He found the root cause was usually a simple problem and shares how to fix them without much trouble.

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Bringing The Best Laptop Ever Made Back To Life

February 7, 2017 by Brian Benchoff 60 Comments

Eight or nine years ago, Apple was on top of the world. The iPhone just revolutionized phones, Apple was still making computers, and these computers were actually repairable. Of the late 2008/early 2009 MacBook Pro, iFixit said, “What an incredible machine. We are very impressed by the ease with which the new MacBook Pro came apart. This machine should be a joy to work on”. Apple has come a long way since then.

[DocDawning] has a bit of a Mac hoarding problem, and frequently pays $20 for broken laptops of this vintage. Most of the time, the fix is simple: the RAM needs to be reseated, or something like that. Rarely, he comes across a machine that isn’t fixed so easily. The solution, in this case, is a deep dive into heat guns and thermal management. How do you bring a laptop back from the dead? [Dawning] shows you how.

Like the old XBox towel hack, the first thing to look for in dead electronics is broken solder balls. Of course, actually looking at broken solder balls is pretty hard, so you might as well just get out a heat gun and go at it. That’s exactly what [Dawning] did. With the clever application of an aluminum takeout tray to direct the heat flow, he blasted each of these chips with enough heat to hopefully melt all the balls.

With that, a working MacBook Pro was just a liberal application of thermal paste away. From $20 at the scrap heap to a working computer, [Dawning] did it. He successfully resuscitated a broken computer.

$2700 EBay Bet Pays Off For This 14 GHz Spectrum Analyzer Repair

January 29, 2017 by Dan Maloney 75 Comments

The eBay addiction starts small. One night you’re buying $3 buck-boost converters and cheap Chinese USB power packs. The next thing you know you’re spending thousands on dead instruments with no documentation. You’ve got the skills though, and if your bet that you can diagnose and repair a 14 GHz real-time spectrum analyzer is right, you’ll be putting a snazzy instrument on the bench for a fraction of the original $50,000 it cost.

Make some popcorn and get cozy before settling in to watch [Shahriar]’s video below, because it clocks in at just over an hour. But it’s pretty entertaining, and just seeing how Tektronix built the RSA 6114A spectrum analyzer is worth the time. Things are different when you’re piping microwave signals around the chassis of a beast such a this, the interior of which is densely packed with pluggable modules. Tek factory service would no doubt perform a simple module swap to get this machine running again, but [Shahriar] wasn’t having any of that on his $2,700 eBay find. After isolating the problem to the local-oscillator generator module, [Shahriar] takes us on a tour of where the signals go and what they do. We won’t reveal the eventual culprit, but suffice it to say that after a little SMD rework, [Shahriar] has a very fancy new instrument for the shop.

If this repair gives you the itch to get working on microwave circuits, maybe it’s time to build that backyard synthetic aperture radar set you’ve always wanted.

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