Chip decapping videos are a staple of the hacking world, and few things compare to the beauty of a silicon die stripped of its protective epoxy and photographed through a good microscope. But the process of actually opening that black resin treasure chest seems elusive, requiring as it does a witch’s brew of solvents and acids.
Or does it? As [Curious Marc] documents in the video below, a little heat and some finesse are all it takes, at least for some chips. The method is demonstrated by [Antoine Bercovici], a paleobotanist who sidelines as a collector of old chips. After removing chips from a PCB — he harvested these chips from an old PlayStation — he uses hot air to soften the epoxy, and then flexes the chip with a couple of pairs of pliers. It’s a bit brutal, but in most of the Sony chips he tried for the video, the epoxy broke cleanly over the die and formed a cleavage plane that allowed the die to be slipped out cleanly. The process is not unlike revealing fossils in sedimentary rocks, a process that he’s familiar with from his day job.
He does warn that certain manufacturers, like Motorola and National, use resins that tend to stick to the die more. It’s also clear that a hairdryer doesn’t deliver enough heat; when they switched to a hot air rework station, the success rate went way up.
The simplicity of this method should open the decapping hobby up to more people. Whether you just want to take pretty pictures or if reverse engineering is on your mind, put the white fuming nitric acid down and grab the heat gun instead.
[Voltlog] has had a 952 hot air rework station for a long time. You’ll recognize it when you see it — they are the ubiquitous soldering iron and hot air gun combination from China sold under numerous brand names. He didn’t think the old station was as good as some of the newer devices available, and did a teardown and review of the BST-863 station that can be had for well under $200. You can see the video below.
He was impressed with the build quality of the workpiece holder. It lets you store the hot air gun and keep it in standby mode. He liked the touchscreen, too, although the beeping seemed a bit annoying. However, in general, the operating noise was less than the older unit it replaced.
We all have that friend who brings us their sad busted electronics. In [Leo’s] case, he had a MIDI sequencer from a musician friend. It had a dead display and the manufacturer advised that a driver IC was probably bad, even sending a replacement surface mount part.
[Leo] wasn’t convinced though. He knew that people were always pushing on the switches that were mounted on the board and he speculated that it might just be a bad solder joint. As you can see in the video below, that didn’t prove out.
The next step was to fire up a hot air gun. Instead of removing the chip, he wanted to reflow the solder anyway. He was a little worried about melting the 7-segment LEDs so he built a little foil shield to protect it. That didn’t get things working, either.
If your workshop has ceilings as high as [Niklas Roy]’s 3.6 meters (11.8 feet), then you’re familiar with his problem. Hot air rises, and there it usually stays until the heat is transferred outdoors. But in the winter time we need that heat indoors and down low. One solution is to install ceiling fans that blow that hot air back down. However, [Niklas] often builds tall things that would collide with those fans. And so he had to hack together some wall hugging fans which will be both high up and out of the way.
For the fans he’s using six of those ubiquitous standing fans, the ones that normally sit on a post a few feet off the ground and swivel back and forth. Discarding the posts, he mounted the fan bodies to a horizontal wooden frame with a wheel attached to one end, one that he’d made for another project. A rope around the wheel, and hanging down, makes it easy to tilt the fans. For controlling the fans, a friend had given him an old industrial controller, and opening it up, all he saw was corrosion. Cleaning it all out he installed an old Russian 3-position switch from his collection.
In the future he’d like to add a closed-loop control system that would not only turn the fans on and off but also adjusting their speed. For now, however, he reports that it works really well. Check out his page for build photos and more details.
Meanwhile, winter really is coming to these northern latitudes and so here are more hacks to prepare you. For automated shovelling snow, how about an RC controlled 3D printed snow blower. And while you’re snug and warm inside remotely controlling your snow blower, you can still be getting exercise using a DIY bicycle roller. But if you do venture outside, perhaps you’d want to zip around on a dogless dog sleigh.
If you’ve ever cringed over throwing away any printer filament you know wouldn’t cover your next small part — let alone an overnight print — you may appreciate [starlino]’s method for joining two spools of filament together.
While there are other methods to track how much filament you’re using, this method removes some of the guesswork. First, snip the ends of the filament on a diagonal — as close to the same angle as possible. Cover both ends with shrink wrap tubing — 2mm tubing for 1.75mm filament for example — ensuring that the two ends overlap inside the wrap. Tape the filament to a heat resistant mat with Kapton tape, leaving exposed the joint between the two filaments. A temperature sensor may help you to find your filament’s melting point, or you can experiment as necessary to get a feel for it.
Melt the filament inside the tubing with a hot air soldering station or heat gun and cool it down promptly with a few blasts from an air duster. All that’s left is to cut the filament free of the tape and shrink wrap, scraping away any excess so as to prevent printer jams. Done! Now, back to printing! Check out the tutorial video after the break.nning
Halloween is coming, and that means dressing children up as pirates, fairies, characters from the latest Marvel and Disney movies, and electrolytic capacitors.
There’s a new movie on [Steve Jobs]. It’s called the Jobs S. It’s a major upgrade of the previous release, featuring a faster processor and more retinas. One more thing. Someone is trying to cash in on [Woz]’s work. This time it’s an auction for a complete Apple I that’s expected to go for $770,000 USD.
Microcontroller Dev Boards have the main hardware choices already made for you so you can jump right into the prototyping by adding peripherals and writing code. Some of the time they have everything you need, other times you can find your own workarounds, but did you ever try just swapping out components to suit? [Andy Brown] documented his process of transplanting the clock crystal on an STM32F4 Discovery board.
Even if you don’t need to do this for yourself, the rework process he documented in the clip after the break is fun to watch. He starts by cleaning the through-hole joints of the crystal oscillator with isopropyl alcohol and then applies some flux paste to each. From there the rest is all hot air. The crystal nearly falls out due to gravity but at the end he needs to pluck it out with his fingers. We’re happy to see others using this “method” as we always feel like it’s a kludge when we do it. Next he grabs the load caps with a pair of tweezers after the briefest of time under the heat.
We’d like to have a little bit of insight on the parts he replaces and we’re hoping there are a few crystal oscillator experts who can leave a comment below. [Andy] calculates a pair of 30pf load caps for this crystal. We understand the math but he mentions a common value for board and uC input capacitance:
assuming the commonly quoted CP + CI = 6pF
So we asked and [Andy] was kind enough to share his background on the topic:
It’s a general “rule of thumb” for FR4 that the stray capacitance due to the traces on the board and the input (lead) capacitance of the the MCU is in in the range of 4-8pF. I’m used to quoting the two separately (CP,CI) but if you look around you’ll see that most people will combine the two and call it just “CP” and quote a value somewhere between 4 and 8pF. It’s all very “finger in the air” and for general purpose MCU clocks you can get away picking the mid-value and be done with it.
That leaves just one other question; the original discovery board had an in-line resistor on one of the crystal traces which he replaces with a zero ohm jumper. Is it common to include a resistor and what is the purpose for it?