classic hacks

2658 Articles

Hacking A Very Special 486

July 21, 2018 by 23 Comments

It’s fair to say that Moore’s Law is not delivering on its promise of advancing semiconductor capabilities as fast as it used to, as the limits of current fabrication techniques are being met. Where this is being written for example there are two laptops, one from the last year and one that is 11 years old, and while the new one is undeniably faster it has not overtaken the other by as much as a ten year gap between 1990s machines would have revealed.

So with older laptops being still so relatively quick, what possible attraction could there be for working on a machine from the 1990s, when the Moore’s Law curve was steeper? It’s something [Jim W] is doing, with his HP Internet Advisor (J2522B), and when you see the machine in question perhaps you’ll understand why. The J2522B is a laptop, but it’s no ordinary ’90s road warrior’s status symbol. This 486-powered beast is a piece of test equipment, specifically one for examining Ethernet ports, thus it’s built like a tank and is mains powered only. It boasts a 486DX4, 16 MB of memory, a then-colossal 1.3 GB hard drive, and an ISA Fast Ethernet card. Oh, and WIndows 95, which with a couple of decades’ hindsight seems an amusing choice to power a piece of security test equipment.  Impressive specs for the day, but the $20,000 price tag would still have been steep compared to a comparable laptop.

[Jim]’s machine is destined for classic gaming, though with only the little HP pop-out mouse you saw on their Omnibook range at the time, he needed a PS/2 port. Some chipset hunting found that, but at the cost of accidentally frying a MOSFET when a screen connector was incorrectly re-inserted. We’re then treated to a guide to substituting older MOSFETs with modern parts, useful in itself, but followed by a marvelous piece of bodge work as an SOIC-8 part is placed on a DPAK footprint.

This is an interesting series of posts, partly from a retro angle as they deal with an interesting machine, but also from a hacking angle as he’s getting closer to the vintage PC hardware than most of us to. Keep an eye on it, there is sure to be more in the pipeline.

A Tale Of More Than One Amiga 1500

July 14, 2018 by 32 Comments

If you were an Amiga enthusiast back in the day, the chances are you had an Amiga 500, and lusted after a 2000 or maybe later a 3000. Later still perhaps you had a 600 or a 1200, and your object of desire became the 4000. The amusingly inept Commodore marketing department repackaged what was essentially the same 68000-based Amiga at the bottom end of the range through the platform’s entire lifetime under their ownership, with a few minor hardware upgrades in the form of chipset revisions that added a relatively small number of features.

We’ve probably listed above all the various Amigas you’ll be familiar with, with a few exceptions you either didn’t have or only saw in magazines. The original A1000, the chipset-upgraded A500+, the CDTV multimedia  platform, or the CD32 games console as examples. But there’s one we haven’t listed which you may never have seen unless you hail from the United Kingdom, and it’s an Amiga behind which lies a fascinating tale that has been unearthed by [RetroManCave].

In the late 1980s, Commodore sold the A500 all-in-one cased Amiga to consumers with marketing based heavily upon gaming, and the A2000 desktop Amiga to businesses with the promise of productivity software. Both machines had a 16-bit Motorola 68000 running at the same speed, with the A2000 having a lot of extra memory and a hard drive lurking within that case. The price difference between the two was inordinately high, creating a niche for an enterprising British company called Checkmate Computers to fill with their provocatively named A1500, a clever case for an A500 mainboard that gave it an expansion slot and space for that hard drive and memory.

This machine’s existence angered Commodore, to the extent that they vowed to eradicate the upstart by releasing their own UK-only A1500. The result, a comically badly concealed rebadge of an A2000 with two floppies and no hard drive, is something we remember seeing at the time, and dare we admit it, even lusting after. But the full story in the video below is well worth a watch for an engrossing insight into a little-known saga in one corner of the computing world during the 16-bt era. Towards the end it becomes a plug for the Checkmate Computers co-founder’s current Kickstarter project, but if that holds no interest for you then you are at least forewarned.

Of course, if you have either A1500 today, you might want an up-to-date graphics card for it.

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Old Time Traffic Signal Revived With A Raspberry Pi Controller

July 12, 2018 by 28 Comments

Anyone with even a passing familiarity with the classic animated shorts of the 1940s will recognize the traffic signal in the image above. Yes, such things actually existed in the real world, not just in the Looney world of [Bugs Bunny] et al. As sturdy as such devices were, they don’t last forever, though, which is why a restoration of this classic Acme traffic signal was necessary for a California museum. Yes, that Acme.

When you see a traffic signal from the early days of the automotive age like this one, it becomes quickly apparent how good the modern equivalent has become. Back in the day, with a mix of lights distributed all over the body of the signal, arms that extend out, and bells that ring when the state changes, it’s easy to see how things could get out of hand at an intersection. That complexity made the restoration project by [am1034481] and colleagues at the Southern California Traffic Museum all the more difficult. Each signal has three lights, a motor for the flag, and an annunciator bell, each requiring a relay. What’s more, the motor needs to run in both directions, so a reversing relay is needed, and the arm has a mechanism to keep it in position when motor power is removed, which needs yet another relay. With two signals, everything was doubled, so the new controller used a 16-channel relay board and a Raspberry Pi to run through various demos. To keep induced currents from wreaking havoc, zero-crossing solid state relays were used on the big AC motors and coils in the signal. It looks like a lot of work, but the end results are worth it.

Looking for more information on traffic signal controls? We talked about that a while back.

A Graph Plotting Metal Detector

July 11, 2018 by 31 Comments

Metal detectors can be a great source of fun, and occasionally even found wealth. They allow the detection of metal objects at a distance, enabling hidden treasures to be discovered. They’re also highly critical to the work of minesweepers and unexploded ordnance disposal teams. [Andrius] wanted to add such a device to his kit when motorcycling through the woods of Lithuania, and thus decided to undertake a build of his own. (Editor’s note: original link went bad, this is through the Wayback Machine.)

The detector is a thoroughly modern one – fans of the 555 may want to look away now. A Collpits oscillator, built from two transistors, is used to generate a frequency that is passed through the detection coil. This frequency is measured by an Arduino that plots a graph of the received frequency on an OLED display. As the coil is passed near metal objects, the oscillator frequency changes, and this is visible on the frequency plot on-screen.

Not only is it a quick and easy build that is achievable from what are now junkdraw components, it’s also one that would be readily usable by the hearing-impaired, too. It’s a great project to tackle if you’re looking to get to grips with basic oscillators, frequency measurement, or just microcontroller programming in general.

Still need more inspiration? We’ve seen a similar concept executed before.

An Amiga 600 With An FPGA Inside

July 10, 2018 by 24 Comments

The Amiga is the platform that refuses to die. It must be more than two decades since the debacle surrounding the demise of the original hardware, yet the operating system is still receiving periodic updates, you can still buy Amiga hardware now sporting considerably more powerful silicon than the originals, and its worldwide community is as active as ever.

One of those community projects is the MiSTer FPGA Amiga-on-an-FPGA, and it was this that caught the attention of [Mattsoft]. Impressed with the quality of its recreation of an Amiga, he decided to turn his into a “real” Amiga, so found an Amiga 600 case and keyboard, and set to work. Into the mix went the Terasic DE10-Nano FPGA board, I/O and RAM boards, a Tynemouth Software keyboard interface, a USB hub, and some well-designed 3D-printed parts allow the original Amiga case to be used without modifications.

The Amiga 600 was the base model in the final Amiga range from the early 1990s, and at the time despite its HDD interface and PCMCIA slot it languished in the shadow of its Amiga 1200 sibling. The styling has aged well though, and this upgrade certainly breathes a little life back into the case if not strictly the machine itself. If you want to learn a bit more about MiSTer then a look at the project’s wiki is in order. Perhaps you don’t have an Amiga though and would like to wallow in a bit of nostalgia without splashing out for hardware, in that case, give AROS a look.

Thanks [intric8] for the tip.

Vintage eight transistor stereo amplifier

Eight Transistor Stereo Amplifier From The Days Of Yore

July 9, 2018 by 31 Comments

Reading an article about the first transistorized Hi-Fi amplifier, [Netzener] got the itch to make one. But what to use for the starting point? Enter an old Radio Shack P-Box stereo amplifier kit. After a few modernizations and tweaks, the result is an 8-transistor stereo amplifier that’s aesthetically pleasing, sounds great, and is fully documented.

The Radio Shack kit used germanium transistors, but with their high leakage current and low thermal conductivity, he decided to convert it to work with silicon transistors. He also made some improvements to the push-pull bias circuit and limited the high-frequency response. As for the finished product, in true [Netzener] style, he assembled it all to look like the original completed Radio Shack amplifier. He even wrote up a manual which you’d think, as we did at first, was the original one, giving that old, comfortable feeling of reading quality Radio Shack documentation.

Check out the video below where he uses a 9 V battery and half a watt per channel to fill a room with clear, stereo sound.

This isn’t the first Radio Shack kit that [Netzener] has adapted. Check out his single tube radio and classic neon “Goofy Light” box.

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