Fail of the Week: Project Frosty Mug is Merely Chilly

Like many of us, [C] enjoys an ice-cold, refreshing soda while coding. Driven by a strong desire to keep a soda ice-cold indefinitely without using ice, [C] started Project Frosty Mug.

[C]’s stated goal is to keep a 20oz plastic bottle of soda at ~35F indefinitely while it sits in a room temperature environment. He started with a thermoelectric unit to cool an aluminium disc, like a cold coaster. Builds one and two made him realize that dealing with the generated heat was a big issue: it got so hot that it deformed the PLA frame. [C] also realized that bottom-only cooling wasn’t going to get the job done.

This project is now in its third build, which is pictured above. As you can see, it’s more koozie than coaster. That 3-D printed holster is lined with aluminium sheeting. Another flat piece covers the opening and attaches to the cooling element. A beefy CPU heat sink does its best, and a couple of U-brackets hold it all together.

[C]’s tested it with a glass bottle of Diet Sun Drop chilled to 38F. After 30 minutes in an ambient temperature of ~70F, the soda measured 45F. [C] lamented having not used a control bottle for comparison and reports that the power supply became quite warm. [C] isn’t going to give up that easily. Do you have any ideas for the fourth build?

Editor’s Note: This is one of the last Fail of the Week tips we have stored up. If you want to see the series continue on a weekly basis, we need help finding more documented fails! Please look back through your projects and document the ones that didn’t go quite right. We also encourage you to send in links to other fails you’ve found. Just drop the links in our tips line. Thanks!

2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which runs every Thursday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.


Welcome to the Old School: Restoring Antique Radios

Before the second world war Radio was a revolution in mass-communication much like the internet today. Fortunes were made and lost, empires built, epic patent battles ensued, all of which resulted in the world being more connected than ever before, which makes for a really great story (and a great Ken Burns documentary).

Last month we showed you how to modify a vintage radio to play your own audio source through it while re-using the existing electronics and maintaining its functionality. In this post we will show you how to restore any vacuum tube radio. You will learn basic repair/restoration procedures from a different era when it was actually worth repairing consumer electronics. Plug into history and get your hands on the most influential technology of the first-half of the 20th century!

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SMT and Thru-Hole Desoldering

My introduction to electronic manufacturing was as a production technician at Pennsylvania Scale Company in Leola PA in the early 1980’s. I learned that to work on what I wanted to work on I had to get my assigned duties done by noon or thereabouts. The most important lesson I had learned as a TV repairman, other than not to chew on the high voltage cable, was to use your eyes first. I would take a box of bad PCB’s that were essentially 6502 based computers that could count and weigh, and first go through inspecting them; usually the contents were reduced 50% right off by doing this. Then it was a race to identify and fix the remaining units and to keep my pace up I had to do my own desoldering.

Desoldering with IR System
Desoldering with IR System

It worked like this; you could set units aside with instructions and the production people would at some point go through changing components etc. for you or you could desolder yourself. I was pretty good at hand de-soldering 28 and 40 pin chips using a venerable Soldapulit manual solder sucker (as they were known). But to really cook I would wait for a moment when the production de-soldering machine was available. There was one simple rule for using the desoldering station: clean it when done! Failure to do so would result in your access to the station being suspended and then you might also incur the “wrath of production” which was not limited to your lunch bag being found frozen solid or your chair soaked in defluxing chemicals.

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Reverse Engineering a NAND Flash Device Management Algorithm

unsoldered flash chip

Put your hand under you chin as here comes a 6 months long jaw-dropping reverse engineering work: getting the data back from a (not so) broken SD card. As you can guess from the picture above, [Joshua]’s first step was to desolder the card’s Flash chip as the tear-down revealed that only the integrated SD-to-NAND Flash controller was damaged. The flash was then soldered on a breadboard so it could be connected to a Digilent Nexys-2 FPGA board. [Joshua] managed to find a similar Flash datasheet, checked that his wire-made bus was reliable and generated two 12GiB dump files on his computer.

In order to extract meaningful data from the dumps he first had to understand how SD-to-NAND controllers work. In his great write-up he provides us with a background of the Flash technology, so our readers can better understand the challenges we face with today’s chips. As flash memories integrate more storage space while keeping the same size, they become less reliable and have nifty problems that should be taken care of. Controllers therefore have to perform data whitening (so neighboring blocks of data don’t have similar content), spread data writes uniformly around the flash (so physical blocks have the same life expectancy) and finally support error correcting codes (so damaged bits can still be recovered). We’ll let our users imagine how complex reverse engineering the implementation of such techniques is when you don’t know anything about the controller. [Joshua] therefore had to do a lot of research, perform a lot of statistical analysis on the data he extracted and when nothing else was possible, use bruteforce…

Fixing A BASIC Calculator

HPThe early days of modern computing were downright weird, and the HP 9830B is a strange one indeed: it’s a gigantic calculator, running BASIC, on a CPU implemented over a dozen cards using discrete logic. In 2014 dollars, this calculator cost somewhere in the neighborhood of $50,000. [Mattis] runs a retrocomputer museum and recently acquired one of these ancient machines, and the walkthrough of what it took to get this old machine running is a great read.

There were several things wrong with this old computer when it arrived: the keyboard had both missing key caps and broken switches. The switches were made by Cherry, but no one at Cherry – or any of the mechanical keyboard forums around the Internet – have ever seen these switches. Luckily, the key cap connector isn’t that complex, and a little bit of bent wire brings the switches back up to spec. The key caps were replaced from a few collectors around the globe.

Getting as far as booting the machine, [Mattis] found some weirdness when using this old calculator: the result of 2+2 was 8.4444444, and 3+1 was 6.4444444. Simply pressing the number 0 and pressing execute resulted in 2 being displayed. With a little bit of guesswork, [Mattis] figured this was a problem with the ALU, and inspecting the ROM on that board proved to be correct: the first 128 nibbles of the ROM were what they were supposed to be, and the last 128 nibbles were the OR of the last half. A strange error, but something that could be fixed with a new replacement ROM.

After hunting down errors with the printer and the disk drive, [Mattis] eventually got this old calculator working again. For such an astonishingly complex piece of equipment, the errors were relatively easy to hunt down, once [Mattis] had the schematics for everything. You can’t say that about many machines only 10 years younger than this old calculator, but then again, they didn’t cost as much as a house.

Finding And Repairing Microscopes From The Trash

scope We’re not quite sure where [Andy] hangs out, but he recently found a pile of broken microscopes in a dumpster. They’re old and obsolete microscopes made for biological specimens and not inspecting surface mount devices and electronic components, but the quality of the optics is outstanding and hey, free microscope.

There was a problem with these old scopes – the bulb used to illuminate specimens was made out of pure unobtainium, meaning [Andy] would have to rig up his own fix. The easiest way to do that? Some LEDs made for car headlights, of course.

The maker of these scopes did produce a few for export to be used in rural areas all across the globe. These models had a 12 Volt input to allow the use of a car battery to light the bulb. A LED headlight also runs off 12 Volts, so it was easy for [Andy] to choose a light source for this repair.

A little bit of dremeling later, and [Andy] had the new bulb in place. An off the shelf PWM controller can vary the brightness of the LED, controlled with the original Bakelite knob. The completed scope can easily inspect human hairs, the dust mites, blood cells, and just about anything down to the limits of optical microscopy. Future plans for this microscope might include another project on, a stage automator that will allow the imaging of huge fields at very high magnification – not bad for something pulled out of the trash.

Dodgy Hotel, Beer and A WWII Era Tube Receiver

bc-22e ww2 reciever operating in a hotel

In the luxurious accommodations provided by Motel 8 and armed only with a few tools and a six pack – a pair of amateur radio enthusiasts attempted the repair of an old WWII era BC-224E receiver. They picked up the boat anchor antique receiver, which was in unknown condition, from a flea market while in town for the Dayton Hamvention, brought it back to their hotel and got to work.

The BC-224E came in two parts – the receiver and the power supply. The speaker for the system, which is actually located in the power supply, is driven by a large inductor.  Apparently when the receiver was constructed, the permanent magnets of the day were not powerful enough to drive a speaker.

Fortunately, the receiver also came with some schematics, allowing [Gregory] and his fellow radio enthusiast to reverse engineer the power supply. After a few tweaks and cap swaps, they crossed their fingers and plugged it in. Stay tuned to see what happened next.

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