Fault Analysis Of A 120W Anker GaNPrime Charger

May 21, 2025 by Maya Posch 39 Comments

Taking a break from his usual prodding at suspicious AliExpress USB chargers, [DiodeGoneWild] recently had a gander at what used to be a good USB charger.

The Anker 737 USB charger prior to its autopsy. (Credit: DiodeGoneWild, YouTube) — The Anker 737 USB charger prior to its autopsy.

Before it went completely dead, the Anker 737 GaNPrime USB charger which a viewer sent him was capable of up to 120 Watts combined across its two USB-C and one USB-A outputs. Naturally the charger’s enclosure couldn’t be opened non-destructively, and it turned out to have (soft) potting compound filling up the voids, making it a treat to diagnose. Suffice it to say that these devices are not designed to be repaired.

With it being an autopsy, the unit got broken down into the individual PCBs, with a short detected that eventually got traced down to an IC marked ‘SW3536’, which is one of the ICs that communicates with the connected USB device to negotiate the voltage. With the one IC having shorted, it appears that it rendered the entire charger into an expensive paperweight.

Since the charger was already in pieces, the rest of the circuit and its ICs were also analyzed. Here the gallium nitride (GaN) part was found in the Navitas GaNFast NV6136A FET with integrated gate driver, along with an Infineon CoolGaN IGI60F1414A1L integrated power stage. Unfortunately all of the cool technology was rendered useless by one component developing a short, even if it made for a fascinating look inside one of these very chonky USB chargers.

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Plugging Plasma Leaks In Magnetic Confinement With New Guiding Center Model

May 20, 2025 by Maya Posch 8 Comments

Although the idea of containing a plasma within a magnetic field seems straightforward at first, plasmas are highly dynamic systems that will happily escape magnetic confinement if given half a chance. This poses a major problem in nuclear fusion reactors and similar, where escaping particles like alpha (helium) particles from the magnetic containment will erode the reactor wall, among other issues. For stellarators in particular the plasma dynamics are calculated as precisely as possible so that the magnetic field works with rather than against the plasma motion, with so far pretty good results.

Now researchers at the University of Texas reckon that they can improve on these plasma system calculations with a new, more precise and efficient method. Their suggested non-perturbative guiding center model is published in (paywalled) Physical Review Letters, with a preprint available on Arxiv.

The current perturbative guiding center model admittedly works well enough that even the article authors admit to e.g. Wendelstein 7-X being within a few % of being perfectly optimized. While we wouldn’t dare to take a poke at what exactly this ‘data-driven symmetry theory’ approach exactly does differently, it suggests the use machine-learning based on simulation data, which then presumably does a better job at describing the movement of alpha particles through the magnetic field than traditional simulations.

Top image: Interior of the Wendelstein 7-X stellarator during maintenance.

The World Wide Web And The Death Of Graceful Degradation

May 20, 2025 by Maya Posch 76 Comments

In the early days of the World Wide Web – with the Year 2000 and the threat of a global collapse of society were still years away – the crafting of a website on the WWW was both special and increasingly more common. Courtesy of free hosting services popping up left and right in a landscape still mercifully devoid of today’s ‘social media’, the WWW’s democratizing influence allowed anyone to try their hands at web design. With varying results, as those of us who ventured into the Geocities wilds can attest to.

Back then we naturally had web standards, courtesy of the W3C, though Microsoft, Netscape, etc. tried to upstage each other with varying implementation levels (e.g. no iframes in Netscape 4.7) and various proprietary HTML and CSS tags. Most people were on dial-up or equivalently anemic internet connections, so designing a website could be a painful lesson in optimization and targeting the lowest common denominator.

This was also the era of graceful degradation, where us web designers had it hammered into our skulls that using and navigating a website should be possible even in a text-only browser like Lynx, w3m or antique browsers like IE 3.x. Fast-forward a few decades and today the inverse is true, where it is your responsibility as a website visitor to have the latest browser and fastest internet connection, or you may even be denied access.

What exactly happened to flip everything upside-down, and is this truly the WWW that we want?

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3D Printing Uranium-Carbide Structures For Nuclear Applications

May 19, 2025 by Maya Posch 11 Comments

Fabrication of uranium-based components via DLP. (Zanini et al., Advanced Functional Materials, 2024)

Within the nuclear sciences, including fuel production and nuclear medicine (radiopharmaceuticals), often specific isotopes have to be produced as efficiently as possible, or allow for the formation of (gaseous) fission products and improved cooling without compromising the fuel. Here having the target material possess an optimized 3D shape to increase surface area and safely expel gases during nuclear fission can be hugely beneficial, but producing these shapes in an efficient way is complicated. Here using photopolymer-based stereolithography (SLA) as recently demonstrated by [Alice Zanini] et al. with a research article in Advanced Functional Materials provides an interesting new method to accomplish these goals.

In what is essentially the same as what a hobbyist resin-based SLA printer does, the photopolymer here is composed of uranyl ions as the photoactive component along with carbon precursors, creating solid uranium dicarbide (UC₂) structures upon exposure to UV light with subsequent sintering. Uranium-carbide is one of the alternatives being considered for today’s uranium ceramic fuels in fission reactors, with this method possibly providing a reasonable manufacturing method.

Uranium carbide is also used as one of the target materials in ISOL (isotope separation on-line) facilities like CERN’s ISOLDE, where having precise control over the molecular structure of the target could optimize isotope production. Ideally equivalent photocatalysts to uranyl can be found to create other optimized targets made of other isotopes as well, but as a demonstration of how SLA (DLP or otherwise) stands to transform the nuclear sciences and industries.

The Nightmare Of Jailbreaking A ‘Pay-To-Ride’ Gotcha Ebike

May 19, 2025 by Maya Posch 37 Comments

Theoretically bicycle rental services are a great thing, as they give anyone the means to travel around comfortably without immediately having to rent a car, hail a taxi or brave whatever the local public transport options may be. That is until said services go out of business and suddenly thousands of increasingly more proprietary and locked-down e-bikes suddenly are at risk of becoming e-waste. So too with a recent acquisition by [Berm Peak] over at YouTube, featuring a ‘Gotcha’ e-bike by Bolt Mobility, which went AWOL back in 2022, leaving behind thousands of these e-bikes.

So how hard could it be to take one of these proprietary e-bikes and turn it into a run-off-the-mill e-bike for daily use? As it turns out, very hard. While getting the (36V) battery released and recharged was easy enough, the challenge came with the rest of the electronics, with a veritable explosion of wiring, the Tongsheng controller module and the ‘Gotcha’ computer module that locks it all down. While one could rip this all out and replace it, that would make the cost-effectiveness of getting one of these go down the drain.

Sadly, reverse-engineering the existing system proved to be too much of a hassle, so a new controller was installed along with a bunch of hacks to make the lights and new controller work. Still, for $75 for the bike, installing new electronics may be worth it, assuming you can find replacement parts and got some spare hours (or weeks) to spend on rebuilding it. The bike in the video costed less than $200 in total with new parts, albeit with the cheapest controller, but maybe jailbreaking the original controller could knock that down.

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Mainboard with the two 128 kB EPROMs containing the special MacIntosh Plus ROM image. (Credit: Pierre Dandumont)

The Lost 256 KB Japanese ROM For The Macintosh Plus Has Been Found

May 17, 2025 by Maya Posch 15 Comments

The Apple Macintosh Plus was one of the most long-lived Apple computers and saw three revisions of its 128 kB-sized ROMs during its life time, at least officially. There’s a fourth ROM, sized 256 kB, that merges the Western ROMs with Japanese fonts. This would save a user of a Western MacIntosh Plus precious start-up time & RAM when starting software using these fonts. Unfortunately, this particular ROM existed mostly as a kind of myth, until [Pierre Dandumont] uncovered one (machine-translated, French original).

The two 128 kB EPROMs containing the special MacIntosh Plus ROM image. (Credit: Pierre Dandumont)

Since this particular ROM was rumored to exist somewhere in the Japanese market, [Pierre] went hunting for Japanese Macintosh Plus mainboards, hoping to find a board with this ROM. After finally getting lucky, the next task was to dump the two 128 kB EPROMs. An interesting sidenote here is that the MacIntosh Plus’ two ROM sockets use the typical programming voltage pin (Vpp) as an extra address line, enabling 256 kB of capacity across the two sockets.

This detail probably is why this special ROM wasn’t verified before, as people tried to dump them without using that extra address line, i.e. as a typical 27C512 64 kB EPROM instead of this proprietary pinout, which would have resulted in the same 64 kB dump as from a standard ROM. Thanks to [Doc TB]’s help and his UCA device it was possible to dump the whole image, with the images available for download.

Using this ROM image was the next interesting part, as [Pierre] initially didn’t have a system to test it with, and emulators assume the 128 kB ROM format. Fortunately these are all problems that can be solved, allowing the ROM images to be validated on real hardware as well as a modified MAME build. We were informed by [Pierre] that MAME releases will soon be getting support for this ROM as well.

Voyager 1’s Primary Thrusters Revived Before DSN Command Pause

May 15, 2025 by Maya Posch 42 Comments

As with all aging bodies, clogged tubes form an increasing issue. So too with the 47-year old Voyager 1 spacecraft and its hydrazine thrusters. Over the decades silicon dioxide from an aging rubber diaphragm in the fuel tank has been depositing on the inside of fuel tubes. By switching between primary, backup and trajectory thrusters the Voyager team has been managing this issue and kept the spacecraft oriented towards Earth. Now this team has performed another amazing feat by reviving the primary thrusters that had been deemed a loss since a heater failure back in 2004.

Unlike the backup thrusters, the trajectory thrusters do not provide roll control, so reviving the primary thrusters would buy the mission a precious Plan B if the backup thrusters were to fail. Back in 2004 engineers had determined that the heater failure was likely unfixable, but over twenty years later the team was willing to give it another shot. Analyzing the original failure data indicated that a glitch in the heater control circuit was likely to blame, so they might actually still work fine.

To test this theory, the team remotely jiggled the heater controls, enabled the primary thrusters and waited for the spacecraft’s star tracker to drift off course so that the thrusters would be engaged by the onboard computer. Making this extra exciting was scheduled maintenance on the Deep Space Network coming up in a matter of weeks, which would have made troubleshooting impossible for months.

To their relief the changes appears to have worked, with the heaters clearly working again, as are the primary thrusters. With this fix in place, it seems that Voyager 1 will be with us for a while longer, even as we face the inevitable end to the amazing Voyager program.