Repairing An Old Heathkit ‘Scope

February 8, 2025 by Al Williams 8 Comments

With so many cheap oscilloscopes out there, the market for old units isn’t what it used to be. But if you have a really old scope, like the Heathkit O-10 that [Ken] found in his basement, there is vintage cred to having one. [Ken’s] didn’t work, so a repair session ensued. You can see the results in the video below.

You can tell this is in an old scope — probably from the mid 1950s — because of its round tube with no graticle. Like many period scopes, the test probe input was just 5-way binding posts. The O-10 was the first Heathkit “O-series” scope that used printed circuit boards.

The device looked pretty good inside, except for a few dents. Of course, the box has tubes in it, so every power up test involves waiting for the tubes to warm up. [Ken] was very excited when he finally got a single green dot on the screen. That did, however, require a new CRT.

It wasn’t long after that he was able to put a waveform in and the scope did a good job of reproducing it. The unit would look good in an old movie, but might not be the most practical bench instrument these days.

These Heathkit scopes and their cousins were very popular in their day. The $70 price tag sounds cheap, but in the mid-1950s, that was about a month’s rent in a four-room house. While primitive by today’s standards, scopes had come a long way in 9 or 10 years.

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Your Favorite Basic Oscilloscope Operation Guide?

February 8, 2025 by Maya Posch 9 Comments

Like many pieces of lab equipment, oscilloscopes are both extremely useful and rather intimidating to a fledgling user. Unlike a digital multimeter with its point-and-measure functionality, digital storage oscilloscopes (DSOs) require fundamental knowledge before they can be used properly. Yet at the same time nobody likes reading manuals, so what is one to do? Try the Absolute Beginner’s Guide to DSOs by [Arthur Pini]

[Pini’s] Cliff’s Notes version of your scope’s manual isn’t half bad. It covers the basic user interface and usage of a (stand-alone) DSO. Unfortunately, it focuses a bit too much on a fancy touch-screen Teledyne LeCroy MSO rather than something the average hobbyist is likely to have lying around.

We rather like the PSA-type videos such as the classic ‘“How not to blow up your oscilloscope” video by [Dave] over at EEVBlog. Many guides and introductions cover “what to do,” but covering common safety issues like improper grounding, isolation, or voltages might be a better place to start.

What tutorial or reference work would you hand to an oscilloscope newbie? We can endorse a hands-on approach with a suitable test board. We also enjoyed [Alan’s] video on the topic. Even if you are an old hand, do you know how to use all those strange trigger modes?

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Turn Your Phone Into A POV Hologram Display

February 8, 2025 by Al Williams 17 Comments

It seems obvious once you think about it, but if you can spin your cell phone and coordinate the display with the motion, you can create a 3D display. [Action Lab] had used such a setup to make a display that you could view from any angle. After he showed it, a viewer wrote him to mention that if you spin the picture at the same rate, it will appear in 3D. The results look great, as you can see in the video below.

The spinning mechanism in this case is an inexpensive pottery wheel. Whatever you use, though, you need a way to match the speed of the graphics to the speed of the phone’s rotation. For this example, there are just a few pre-spun 3D models on a website. However, creating your own viewer like this wouldn’t be that hard. Even more interesting would be to read the phone sensors and spin the image in sync with the phone’s motion.

We keep hearing about awesome commercial 3D stuff coming out “any day now.” Meanwhile, you can always settle for Pepper’s Cone.

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Jeff Dunham next to a Philco Predicta TV

Jeff Dunham Finds A NOS 1958 Philco Predicta

February 8, 2025 by Heidi Ulrich 14 Comments

When you see a ventriloquist like [Jeff Dunham], you probably expect to see him with a puppet. This time – spoilers ahead – you won’t. Besides his fame on stage, [Dunham] is also a collector of vintage tech and a die-hard television enthusiast. In the video below, [Dunham] has gotten his hands on a rarity: an unboxed 1958 Philco Predicta TV. The original tape was still on the box. We get to follow along on his adventure to restore this sleek, retro-futuristic relic!

[Dunham]’s fascination with the Predicta stems from its historical significance and bold design. At a time when television was making its way into American homes, the Predicta dared to be different with its swivel-mounted picture tube and early printed circuit boards. Despite its brave aesthetics, the Predicta’s ambition led to notorious reliability issues. Yet, finding one in pristine condition, sealed and untouched for over six decades, is like unearthing a technological time capsule.

What makes this story unique is [Dunham]’s connection to both broadcasting and his craft. As a ventriloquist inspired by Edgar Bergen — whose radio shows captivated America — [Dunham] delights in restoring a TV from the same brand that first brought his idol’s voice to airwaves. His love for storytelling seamlessly translates into this restoration adventure.

After unboxing, [Dunham’s] team faces several challenges: navigating fragile components, securing the original shipping brace, and cautiously ramping up voltage to breathe life into the Predicta. The suspense peaks in the satisfying crackle of static, and the flicker of a 65-year-old screen finally awakened from slumber.

Have you ever come across an opportunity like this? Tell us about your favorite new old stock find in the comments. Buying these can be a risk, since components have a shelf life. We appreciate when these old TVs play period-appropriate shows. Who wants to watch Game of Thrones on a Predicta?

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Freed At Last From Patents, Does Anyone Still Care About MP3?

February 8, 2025 by Maya Posch 99 Comments

The MP3 file format was always encumbered with patents, but as of 2017, the last patent finally expired. Although the format became synonymous with the digital music revolution that started in the late 90s, as an audio compression format there is an argument to be made that it has long since been superseded by better formats and other changes. [Ibrahim Diallo] makes that very argument in a recent blog post. In a world with super fast Internet speeds and the abstracting away of music formats behind streaming services, few people still care about MP3.

The last patents for the MP3 format expired in 2012 in the EU and 2017 in the US, ending many years of incessant legal sniping. For those of us learning of the wonders of MP3 back around ’98 through services like Napster or Limewire, MP3s meant downloading music on 56k dialup in a matter of minutes to hours rather than days to weeks with WAV, and with generally better quality than Microsoft’s WMA format at lower bitrates. When portable media players came onto the scene, they were called ‘MP3 players’, a name that stuck around.

But is MP3 really obsolete and best forgotten in the dustbin of history at this point? Would anyone care if computers dropped support for MP3 tomorrow?

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Software In Progress

February 8, 2025 by Elliot Williams 69 Comments

Open source software can be fantastic. I run almost exclusively open software, and have for longer than I care to admit. And although I’m not a serious coder by an stretch, I fill out bug reports when I find them, and poke at edge cases to help the people who do the real work.

For 3D modeling, I’ve been bouncing back and forth between OpenSCAD and FreeCAD. OpenSCAD is basic, extensible, and extremely powerful in the way that a programming language is, and consequently it’s reliably bug-free. But it also isn’t exactly user friendly, unless you’re a user who likes to code, in which case it’s marvelous. FreeCAD is much more of a software tool than a programming language, and is a lot more ambitious than OpenSCAD. FreeCAD is also a program in a different stage of development, and given its very broad scope, it has got a lot of bugs.

I kept running into some really serious bugs in a particular function – thickness for what it’s worth – which is known to be glitchy in the FreeCAD community. Indeed, the last time I kicked the tires on thickness, it was almost entirely useless, and there’s been real progress in the past couple years. It works at least sometimes now, on super-simple geometries, and this promise lead me to find out where it still doesn’t work. So I went through the forums to see what I could do to help, and it struck me that some people, mostly those who come to FreeCAD from commercial programs that were essentially finished a decade ago, have different expectations about the state of the software than I do, and are a lot grumpier.

Open source software is working out its bugs in public. Most open source is software in development. It’s growing, and changing, and you can help it grow or just hang on for the ride. Some open-source userland projects are mature enough that they’re pretty much finished, but the vast majority of open-source projects are coding in public and software in progress.

It seems to me that people who expect software to be done already are frustrated by this, and that when we promote super-star open projects like Inkscape or Blender, which are essentially finished, we are doing a disservice to the vast majority of useful, but still in progress applications out there that can get the job done anyway, but might require some workarounds. It’s exactly these projects that need our help and our bug-hunting, but if you go into them with the “finished” mentality, you’re setting yourself up for frustration.

A Programming Language For Building NES Games

February 8, 2025 by Tom Nardi 27 Comments

Generally speaking, writing your own games for retro consoles starts with C code. You’ll need to feed that through a console-specific tool-chain, and there’s certainly going to be some hoops to jump through, but if everything goes as expected, you should end up with a ROM file that can be run in an emulator or played on real hardware if you’ve got the necessary gadgetry to load it.

But NESFab takes things in a slightly different direction. While the code might look like C, it’s actually a language specifically tailored for developing games on the Nintendo Entertainment System (NES). The documentation claims that this targeted language not only compiles into considerably faster 6502 assembly than plain C on GCC or LLVM, but is designed to work around the strengths (and weaknesses) of the NES hardware.

Looking deeper into the example programs and documentation, NESFab offers quite a few quality of life features that should make developing NES games easier. For one thing, there’s integrated asset loading which automatically converts your image files into something the console can understand. One just needs to drop the image file into the source directory, open it in the code with the file function, and the build system will take care of converting it on the fly as the ROM is built. The nuances of bank switching — the organization of code and assets so they fit onto the physical ROM chips on the NES cartridge — are similarly abstracted away.

The obvious downside of NESFab is that, as with something like GB Studio, you’re going to end up putting effort into learning a programming environment that works for just one system. So before you get started, you really need to decide what your goals are. If you’re a diehard NES fan that has no interest in working on other systems, learning a language and build environment specifically geared to that console might make a certain degree of sense. But if you’d like to see your masterpiece running on more than just one system, working in straight C is still going to be your best bet.