A New Life For An Old Amplifier

An audio amplifier was once a fairly simple analogue device, but in recent decades a typical home entertainment amplifier will have expanded to include many digital functions. When these break they are often proprietary and not easy to repair, as was the case with a broken Pioneer surround-sound device given to [Boz]. It sat on the shelf for a few years until he had the idea of a jukebox for his ripped CDs, and his returning it to life with a new main board is something to behold.

Internally it’s a surprisingly modular design, meaning that the front panel with its VFD display and driver were intact and working, as were the class AB amplifier and its power supply. He had the service manual so reverse engineering was straightforward, thus out came the main board in favor of a replacement. He took the original connectors and a few other components, then designed a PCB to take them and a Raspberry Pi Pico and DAC. With appropriate MMBASIC firmware it looks as though it was originally made this way, a sense heightened by a look at the motherboard inside (ignoring a couple of bodges).

We like seeing projects like this one which revive broken devices, and this one is particularly special quality wise. We’re more used to seeing it with gaming hardware though.

Great Trains, Not So Great AI Chatbot Security

A joy of covering the world of the European hackerspace community is that it offers the chance for train travel across the continent using the ever-good-value Interrail pass. For a British traveler such a journey inevitably starts with a Eurostar train that whisks you in comfort through the Channel Tunnel, so a report of an AI vulnerability on the Eurostar website from [Ross Donald] particularly caught our eye. What it reveals goes beyond the train company, and tells us some interesting tidbits about how safeguards in AI chatbots can be circumvented.

The bot sits on the Eurostar website, and is a simple HTML and JavaScript client that talks to the LLM back-end itself through an API. The API queries contain the whole conversation, because as AI toy manufacturers whose products have been persuaded to spout adult context will tell you, large language models (LLM)s as commonly implemented do not have a context memory for the conversation in hand.

The Eurostar developers had not made a bot without guardrails, but the vulnerability lay in those guardrails only being applied to the most recent message. Thus an innocuous or empty message could be sent, with a payload concealed in a previous message in the conversation. He demonstrates the bot returning system information about itself, and embedding injected HTML and JavaScript in its responses.

He notes that the target of the resulting output could only be himself and that he was unable to access any data from other customers, so perhaps in this case the train operator was fortunately spared the risk of a breach. From his description though, we agree they could have responded to the disclosure in a better manner.


Header image: Eriksw, CC BY-SA 4.0.

Chasing The Coca-Cola Recipe

One of the most widely recognised product brands in the world is probably Coca-Cola, and its formula is famously kept a secret through precautions that probably rival those of many nation states. There are other colas, and there are many amateurs who have tried to copy Coke’s flavour, but in well over a century, nobody has managed it. Why does [LabCoatz] think his attempt will be successful where others failed? He has friends with their own mass spectrometers.

Continue reading “Chasing The Coca-Cola Recipe”

A Much Faster Mac On A Microcontroller

Emulating older computers on microcontrollers has been a staple of retrocomputing for many years now, with most 8-bit and some 16-bit machines available on Atmel, ARM, or ESP32 platforms. But there’s always been a horsepower limit, a point beyond which a microcontroller is no longer enough, and a “proper” computer is needed. One of those barriers now appears to have been broken, as microcontroller-based emulation moves into the 32-bit era. [Amcchord] has the Basilisk II emulator ported to the ESP32-P4 platform, providing a 68040 Mac able to run OS8.1. This early-1990s-spec machine might not seem like much in 2026, but it represents a major step forward.

The hardware it uses is the M5Stack Tab5, and it provides an emulated Mac with up to 16 MB of memory. Remember, in 1992 this would have been a high-spec machine. It manages a 15 frames per second refresh rate, which is adequate for productivity applications. The emulator uses the Tab5’s touchscreen to emulate the Mac mouse alongside support for USB input devices. To 1990 hackers, it’s almost the Mac tablet you didn’t know you would want in the future.

We like this project, both because it’s advancing the art of emulation on microcontrollers, and also because it delivers a computer that’s useful for some of the things you might have done with a Mac in 1992 and could even do today. Pulling this out on the train back then would have blown people’s minds. There’s even a chance that MacOS on something like this would turn a few heads in 2026. It’s certainly not the first emulated Mac we’ve seen though.

A 1990s VNA Gets An LCD

A Vector Network Analyser, or VNA, is the ultimate multi-tool of RF test equipment. They can now be had in not very capable form for almost pocket money prices, but the professional-grade ones cost eye-watering sums. Enough to make an older VNA for a few hundred on eBay a steal, and [W3AXL] has just such a device in an HP 8714C. It’s the height of 1990s tech with a floppy drive and a green-screen CRT, but he’s homing right in on the VGA monitor port on the back. Time for a colour LCD upgrade!

There are two videos below the break, posted a year apart, because as we’re sure many of you will know, events have a habit of getting in the way of projects. In the first, we see the removal of the CRT module and safe extraction of its electronics, followed by the crafting of a display bezel for the LCD. Meanwhile, the second video deals with the VNA itself, extracting the VGA signal and routing it forward to the new module. Continue reading “A 1990s VNA Gets An LCD”

It’s Not A Leica, It’s A Lumix

There’s an old adage in photography that the best camera in the world is the one in your hand when the shot presents itself, but there’s no doubt that a better camera makes a difference to the quality of the final image. Among decent quality cameras the Leica rangefinder models have near cult-like status, but the problem is for would-be Leica owners that they carry eye-watering prices. [Cristian Băluță] approached this problem in s special way, by crafting a Leica-style body for a Panasonic Lumix camera. Given the technology relationship between the Japanese and German companies, we can see the appeal.

While the aesthetics of a Leica are an important consideration, the ergonomics such as the position of the lens on the body dictated the design choices. He was fortunate that the internal design of the Lumix gave plenty of scope for re-arrangement of parts, given that cameras are often extremely packed internally. Some rather bold surgery to the Lumix mainboard and a set of redesigned flex PCBs result in all the parts fitting in the CNC machined case, and the resulting camera certainly looks the part.

The write-up is in part a journey through discovering the process of getting parts manufactured, but it contains a lot of impressive work. Does the performance of the final result match up to its looks? We’ll leave you to be the judge of that. Meanwhile, take a look at another Leica clone.

How Do PAL And NTSC Really Work?

Many projects on these pages do clever things with video. Whether it’s digital or analogue, it’s certain our community can push a humble microcontroller to the limit of its capability. But sometimes the terminology is a little casually applied, and in particular with video there’s an obvious example. We say “PAL”, or “NTSC” to refer to any composite video signal, and perhaps it’s time to delve beyond that into the colour systems those letters convey.

Know Your Sub-carriers From Your Sync Pulses

A close-up on a single line of composite video from a Raspberry Pi.
A close-up on a single line of composite video from a Raspberry Pi.

A video system of the type we’re used to is dot-sequential. It splits an image into pixels and transmits them sequentially, pixel by pixel and line by line. This is the same for an analogue video system as it is for many digital bitmap formats. In the case of a fully analogue TV system there is no individual pixel counting, instead the camera scans across each line in a continuous movement to generate an analogue waveform representing the intensity of light. If you add in a synchronisation pulse at the end of each line and another at the end of each frame you have a video signal.

But crucially it’s not a composite video signal, because it contains only luminance information. It’s a black-and-white image. The first broadcast TV systems as for example the British 405 line and American 525 line systems worked in exactly this way, with the addition of a separate carrier for their accompanying sound. Continue reading “How Do PAL And NTSC Really Work?”