The Mystery Of The Clacking Clanking Scraping Sound

January 4, 2019 by Lewin Day 47 Comments

Hackers tend to face household problems a little differently than ordinary folk. Where the average person sees a painful repair bill or a replacement appliance, the hacker sees a difficult troubleshooting job and the opportunity to save some cash. [trochilidae] was woken one day by the dreaded Clacking Clanking Scraping Sound, or CCSS, and knew that something had to be done.

[trochilidae] reports that usually, the CCSS is due to the child of the house destroying his lodgings, but in this case, the source was laundry based. The Miele tumble dryer was acting up, and in need of some attention. What follows is a troubleshooting process [AvE] would be proud of – careful disassembly to investigate the source of the problem. Initial efforts found a loose bulb that was unrelated, before landing on a mysterious spring that wouldn’t fit back into place. In the end, that’s because it had no right to be there at all – an underwire had escaped from a bra, before becoming entangled in the dryer’s bearing. With the culprit identified and removed, it was a simple reassembly job with some attention also paid to the condenser and filters to keep things in ship-shape.

It just goes to show – a bad noise, if properly investigated in a prompt manner, doesn’t have to be the end of the world. A bit of investigation goes a long way, and can save you a lot of money and heartache.

We’ve seen appliances giving hackers trouble before – like this aging washing machine that got its mechanical brain replaced with an Arduino.

A Daring Search For Answers In Soyuz Mystery

December 26, 2018 by Tom Nardi 67 Comments

If you happened to tune into NASA TV on December 11th, you’d have been treated to a sight perhaps best described as “unprecedented”: Russian cosmonauts roughly cutting away the thermal insulation of a docked Soyuz spacecraft with a knife and makeshift pair of shears. Working in a cloud of material ripped loose during the highly unusual procedure, cosmonauts Oleg Kononenko and Sergey Prokopyev were effectively carving out their own unique place in space history. Their mission was to investigate the external side of the suspicious hole in the Soyuz MS-09 capsule which caused a loss of air pressure on the International Space Station earlier in the year.

That astronauts don’t generally climb out the hatch and use a knife to hack away at the outside of their spacecraft probably goes without saying. Such an event has never happened before, and while nobody can predict the future, odds are it’s not something we’re likely to see again. Keep in mind that this wasn’t some test capsule or a derelict, but a vehicle slated to return three human occupants to Earth in a matter of days. Cutting open a spacecraft in which human lives will shortly be entrusted is not a risk taken likely, and shows how truly desperate the Russian space agency Roscosmos is to find out just who or what put a hole in the side of one of their spacecraft.

Close inspection from the inside of the spacecraft confirmed the hole wasn’t made by an impact with a micrometeorite or tiny piece of space junk as was originally assumed. It appears to have been made with a drill, which really only allows for two possible scenarios: intentional sabotage or a mistake and subsequent cover-up. In either event, a truly heinous crime has been committed and those responsible must be found. As luck would have it the slow leak of air pressure was detected early and the hole was patched before any damage was done, but what if it hadn’t?

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Vintage IBM 1403 Printer Problem Evades An Easy Fix

December 20, 2018 by Donald Papp 15 Comments

The Computer History Museum in Mountain View has two operational IBM 1401 mainframes, which use IBM 1403 high-speed printers. They aren’t some decades-old notion of “high speed” that barely looks sluggish today, either. These monsters slam out ten lines per second thanks to a rotating chain of type slugs and an array of electromagnetic hammers. Every 11.1 microseconds, a character in the chain would be lined up with a hammer, and if the control circuitry identified it as a character that needed to be printed, the hammer behind the paper would drive the paper into the print ribbon and the slug, putting an imprint of the character onto the paper. When one of these printers failed with a sync error, it kicked off some serious troubleshooting to diagnose the problem.

The IBM 1403’s type chain has a repeating set of characters that spins around at high speed. Unlike a typewriter or label maker, the hammers are not inside this unit. The hammers are on the outside, and work by pressing the paper onto the type slugs as the required characters line up.

Investigation of the problem ultimately led to an intermittent connection in a driver card due to a broken PCB trace, but by then some fuses had been blown as well. In the end the printer was brought back online, but possibly with a slightly damaged coil on one of the hammers.

[Ken]’s writeup on the repair process is highly detailed and walks through the kind of troubleshooting and repairs involved when solving problems with vintage electronics. Electrical fundamentals might be the same, but a deep understanding of not only the architecture but also the failure modes of vintage hardware is needed in order to troubleshoot effectively.

If IBM 1401 mainframes and fixing 1403 printers sounds familiar, it’s because a printer fix has been done before. That was due to a different problem, but still a challenging task to narrow down and fix.

The Guts Of Switched Mode Power Supplies, Brought To You By Oscilloscope Repair

December 8, 2018 by Brian Benchoff 22 Comments

The Tektronix 2000 series of oscilloscopes are a mainstay for any electronics lab. They work, they’re relatively cheap, they’re good, and they’re available in just about any surplus electronics store. [Mr.RC-Cam] has been hoarding one of these for twenty years, and like any classic piece of equipment, it needs a little refurbishment every now and again. Now, it’s time. Here’s how you repair one of the best values in analog oscilloscopes.

This repair adventure began when the scope died. There were no lights, no screen trace, and a brief hiss sound when it was powered on. (Ten points if you can guess what that hiss sound was!) Armed with a schematic, [Mr.RC-Cam] dove in and pulled the power supply, being careful to discharge the CRT beforehand.

There were no bulging capacitors, no obviously overheated components, and just a little bit of dust. The only solution was to look at the parts with a meter one at a time. Removing the big caps provided access to a row of diodes, which revealed the culprit: a single shorted diode. This part was ordered, and a few other housekeeping tasks were taken care of. The lithium battery on the processor board responsible for storing the calibration constants was replaced, and the new, smaller, caps got lovely 3D printed mounting flange adapters. Now, this old ‘scope works, and we’ve got a lovely story to tell around the electronic campfire.

Teardown And Repair Of A Police Recorder

November 2, 2018 by Al Williams 9 Comments

You should probably hope you haven’t seen [Techmoan’s] cassette recorder before. That’s because it is a Neal interview recorder that was mainly used by police to tape interrogations. This one was apparently used by the Royal Navy and was sold for parts. Turns out, the repair was simple, but the teardown and the analysis of the machine — you can see it in the video below — is pretty interesting if you’ve never seen one of these before.

The unit looks like a heavy-duty piece of industrial electronics from the 1980s. Unlike a commercial tape deck, this one is made to do one thing: record. You can’t even rewind a tape in it. Also unlike a consumer recorder, the Neal has a few special features aimed at making sure you didn’t miss some important confession on tape. First, it beeps if there’s no microphone plugged in. When [Techmoan] showed the recording head, we noticed it looked like it was split in half. Towards the end of the video, we found out why. In addition, the unit records two tracks: one audio track and another with a voice reading the elapsed time every 10 seconds — pretty high tech for its day.

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You’ll Flip For This 7404 IC Motherboard Fix

October 20, 2018 by Tom Nardi 35 Comments

We often lament that the days of repairable electronics are long gone. It used to be you’d get schematics for a piece of gear, and you could just as easily crack it open and fix something as the local repairman — assuming you had the knowledge and tools. But today, everything is built to be thrown away when something goes wrong, and you might as well check at the end of a rainbow if you’re searching for a circuit diagram for a new piece of consumer electronics.

But [Robson] writes in with an interesting story that gives us hope that the “old ways” aren’t gone completely, though they’ve certainly changed for the 21st century. After blowing out his laptop’s USB ports when he connected a suspect circuit, he was desperate for a fix that would fit his student budget (in other words, nearly zero). Only problem was that he had no experience fixing computers. Oh, and it takes months for his online purchases to reach him in Brazil. Off to a rocky start.

His first bit of luck came with the discovery he could purchase schematics for his laptop online. Now, we can’t vouch for the site he used (it sure isn’t direct from Dell), but for under $5 USD [Robson] apparently got complete and accurate schematics that let him figure out what part was blown on the board without even having to open up the computer. All he had to do was order a replacement IC (SY6288DAAC), and solder it on. It took two months for the parts to arrive, and had to do it with an iron instead of a hot air station, but in the end, he got the part installed.

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Damaged Power Cord Repaired With Shop-Made Mold

September 13, 2018 by Dan Maloney 25 Comments

We’ve likely all seen a power tool with a less-than-functional strain relief at one end of the power cord or the other. Fixing the plug end is easy, but at the tool end things are a little harder and often not worth the effort compared to the price of just replacing the tool. There’s no obsolescence like built-in obsolescence.

But in the land of Festo, that high-quality but exorbitantly priced brand of premium tools, the normal cost-benefit relationship of repairs is skewed. That’s what led [Mark Presling] to custom mold a new strain relief for a broken Festool cord. The dodgy tool is an orbital sander with Festool’s interchangeable “Plug It” type power cord, which could have been replaced for the princely sum of $65. Rather than suffer that disgrace, [Mark] built a mold for a new strain relief from two pieces of aluminum. The mold fits around the cord once it has been slathered with Sugru, a moldable adhesive compound. The video below shows the mold build, which has some interesting tips for the lathe, and the molding process itself. The Sugru was a little touchy about curing, but in the end the new strain relief looks almost like an original part.

Hats off to [Presser] for not taking the easy way out, and for showing off some techniques that could really help around the shop. We suppose the mold could have been 3D-printed rather than machined; after all, we’ve seen such molds before, and that 3D-printed dies can be robust enough to punch metal parts.

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