[Ctrl-Alt-Rees] bought something strange on an auction site: a Japanese Cefucom-21 from 1983. No? Didn’t ring a bell for us either. The legend on the front boldly proclaims: “CCI Multipurpose SLAP Computer,” so maybe it is some kind of computer, but it is definitely strange. For one thing, the “screen” isn’t a screen at all. [Rees] has found that it has something to do with teaching English. You can see the odd beast in the video below.
We don’t know how common these were in Japan, but they appear to be virtually unknown everywhere else. Inside is a Z80 computer based on a Sanyo PHC-25, which is a little better known.
As hackers, we’re always pulling stuff apart—sometimes just to see what it’s like inside. Most of us have seen the inside of a computer, television, and phone. These are all common items that we come into contact with every day. Fewer of us have dived inside real spacey satellite hardware, if only for the lack of opportunity. Some good gear has landed on [Don]’s desk over the years though, so he got to pulling it apart and peering inside.
[Don] starts us off with a gorgeous… box… of some sort from Hughes Aircraft. He believes it to be from their Space & Communications group, and it seems to have something to do with satellite communications work. Externally, he gleans that it takes power and data hookups and outputs RF to, something… but he’s not entirely sure. Inside, we get a look at the old 90s electronics — lots of through hole, lots of big chunky components, and plenty of gold plating. [Don] breaks down the circuitry into various chunks and tries to make sense of it, determining that it’s got some high frequency RF generators in the 20 to 40 GHz range.
Scroll through the rest of [Don]’s thread and you’ll find more gems. He pulls apart a microwave transmitter from Space Micro — a much newer unit built somewhere around 2008-2011. Then he dives into a mysterious I/O board from Broad Reach, and a very old Hughes travelling wave tube from the 1970s. The latter even has a loose link to the Ford Motor Company, believe it or not.
Remember Duracell’s PowerCheck? The idea was that a strip built into the battery would show if the battery was good or not. Sure, you could always get a meter or a dedicated battery tester — but PowerCheck put the tester right in the battery. [Technology Connections] has an interesting video on how these worked and why you don’t see them today. You can see it below.
Duracell didn’t invent the technology. The patent belonged to Kodak, and there were some patent issues, too, but the ones on the Duracell batteries used the Kodak system. In practice, you pushed two dots on the battery, and you could see a color strip that showed how much capacity the battery had left. It did this by measuring the voltage and assuming that the cell’s voltage would track its health. It also assumed — as is clearly printed on the battery — that you were testing at 70 degrees F.
The temperature was important because the secret to the PowerCheck is a liquid crystal that turns color as it gets hot. When you press the dots, the label connects a little resistor, causing the crystals to get warm. The video shows the label taken apart so you can see what’s inside of it. The resistor isn’t linear so that’s how it changes only part of the bar to change color when the battery is weak but not dead.
It is a genius design that is simple enough to print on a label for an extremely low cost and has virtually no components. PowerCheck vanished from batteries almost as suddenly as it appeared. Some of it was due to patent disputes. But the video purports that normal people don’t really test batteries.
If you’re a fan of vintage electronics and DIY tinkering, you’ll find this teardown by [Thomas Scherrer] fascinating. In a recent video, he delves into a rare piece of equipment: the Data Lab Transient Recorder DL 901. This device looks like a classic one-channel oscilloscope, complete with all the knobs and settings you’d expect.
The DL 901, made by Data Laboratories Ltd., is a mystery even to [Thomas], who couldn’t find any documentation online. From the DC offset and trigger settings to the sweep time controls, the DL 901 is equipped to handle slow, high-resolution analog-to-digital conversion. The circuitry includes TTL chips and a PMI DAAC 100, a 10-bit digital-to-analog converter. [Thomas] speculates it uses a successive approximation technique for analog-to-digital conversion—a perfect blend of analog finesse and digital processing for its time.
Despite its intriguing features, the DL 901 suffers from a non-responsive analog input system, limiting the teardown to a partial exploration. For those who enjoyed past Hackaday articles on oscilloscope teardowns and analog tech, this one is a treat. Watch the video to see more details and the full process of uncovering this vintage device’s secrets.
The back of the 2View VHS box. The instructions are all in Dutch, as its (sole) launch market. (Credit: Techmoan, YouTube)
Over the decades the video and music industries have tried a wide range of ways to get consumers to buy ‘cheaper’ versions of albums and music, but then limit the playback in some way. Perhaps one of the most fascinating ones is the 2View, as recently featured by [Matt] over at Techmoan on Youtube. This is a VHS tape which works in standard VHS players and offers you all the goodness that VHS offers, like up to 512 lines of PAL video and hard-coded ads and subtitles, but also is restricted to just playing twice. After this second playback and rewinding, the tape self-erases and is blank, leaving you with just an empty VHS tape you can use for your own recordings.
As a form of analog restrictions management (ARM) it’s pretty simple in how it works, with [Matt] taking the now thankfully erased Coyote Ugly tape apart for a demonstration of the inside mechanism. This consists out of effectively just two parts: one plastic, spring-loaded shape that moves against one of the tape spools and follows the amount of tape, meaning minutes watched, and a second arm featuring a permanent magnet that is retained by an inner track inside the first shape until after rewinding twice it is released and ends up against the second spool, erasing the tape until rewound, after which it catches in a neutral position. This then left an erased tape that could be safely recorded on again.
Although cheaper than a comparable VHS tape without this limit, 2View was released in 2001, when in the Netherlands and elsewhere DVDs were demolishing the VHS market. This, combined with the fact that a simple bent paperclip could be stuck inside to retain the erase arm in place to make it a regular VHS tape, meant that it was really a desperate attempt that quickly vanished off the market
[Ken] recently obtained an attitude indicator—sometimes called an artificial horizon—from an F-4 fighter jet. Unlike some indicators, the F-4’s can rotate to show pitch, roll, and yaw, so it moves in three different directions. [Ken] wondered how that could work, so, like any of us, he took it apart to find out.
With the cover off, the device is a marvel of compact design. Then you realize that some of the circuit is inside the ball, so there’s even more than it appears at a quick glance. As you might have guessed, there are two separate slip rings that allow the ball to turn freely without tangling wires. Of course, even if you don’t tangle wires, getting the ball to reflect the aircraft’s orientation is an exercise in control theory, and [Ken] shows us the servo loop that makes it happen. There’s a gyroscope and synchros—sometimes known by the trade name selsyn—to keep everything in the same position.
You have to be amazed by the designers of things like this. Sophisticated both electrically and mechanically, rugged, compact, and able to handle a lot of stress. Good thing it didn’t have to be cheap.
Structure of the Ramtron FeRAM. The image is focus-stacked for clarity. (Credit: Ken Shirriff)
Although not as prevalent as Flash memory storage, ferroelectric RAM (FeRAM) offers a range of benefits over the former, mostly in terms of endurance and durability, which makes it popular for a range of (niche) applications. Recently [Ken Shirriff] had a look inside a Ramtron FM24C64 FeRAM IC from 1999, to get an idea of how it works. The full die photo can be seen above, and it can store a total of 64 kilobit.
One way to think of FeRAM is as a very small version of magnetic core memory, with lead-zirconate-titanate (PZT) ferroelectric elements making up the individual bits. These PZT elements are used as ferroelectric capacitors, i.e. the ferroelectric material is the dielectric between the two plates, with a positive voltage storing a ‘1’, and vice-versa.
In this particular FeRAM chip, there are two capacitors per bit, which makes it easier to distinguish the polarization state and thus the stored value. Since the distinction between a 0 and a 1 is relatively minor, the sense amplifiers are required to boost the signal. After a read action, the stored value will have been destroyed, necessitating a write-after-read action to restore the value, all of which adds to the required logic to manage the FeRAM. Together with the complexity of integrating these PZT elements into the circuitry this makes these chips relatively hard to produce and scale down.
You can purchase FeRAM off-the-shelf and research is ongoing, but it looks to remain a cool niche technology barring any kind of major breakthrough. That said, the Sega Sonic the Hedgehog 3 cartridges which used an FeRAM chip for save data are probably quite indestructible due to this technology.
