heathkit

34 Articles

’75 Nixie Multimeter As Digital Dice

January 20, 2020 by 10 Comments

For the casual Monopoly or Risk player, using plain six-sided dice is probably fine. For other games you may need dice with much more than six sides, and if you really want to go overboard you can do what [John] did and build electronic dice with a random number generator if you really need to remove the pesky practice of rolling physical dice during your games of chance.

The “digital dice” he built are based on a multimeter from 1975 which has some hardware in it that was worth preserving, including a high quality set of nixie tubes. Nixies can be a little hard to come by these days, but are interesting pieces of hardware in their own right. [John] added some modern hardware to it as well, including an AVR microcontroller that handles the (pseudo) random number generation. A hardware switch tells the microcontroller how many sides the “die” to be emulated will need, and then a button generates the result of the roll.

This is a pretty great use for an old piece of hardware which would otherwise be obsolete by now. [John] considers this a “Resto-Mod” and the finish and quality of the build almost makes it look all original. It’s certainly a conversation piece at the D&D sessions he frequents.

Heathkit’s New RF Meter: Who Is It For?

June 23, 2017 by 25 Comments

Electronic hackers and ham radio operators of a certain age have a soft spot for the Heathkit brand. Maybe that’s why we had a rush of nostalgia when we saw the Heathkit site had a new product. You may recall that Heathkit had gone the way of the dodo until a few years ago when the brand started to resurface. Their latest kit is a precision RF meter which is available on preorder.

Before there were websites and hacker spaces and all the modern push to “do it yourself,” Heathkit was teaching people electronics through kit building. Sure, they were known for ham radio and test equipment, but many people built stereos (hi-fi), TVs, radio control gear, computers, and even robots. All with manuals that are hard to imagine if you haven’t seen one. They were world-class.

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Measuring Capacitors At The Birth Of Rock And Roll

April 15, 2017 by 3 Comments

The late 1950s [Bill Haley], [Elvis Presley], and [Little Richard] were building a new kind of music. Meanwhile, electronic hobbyists were building their own gear from Heathkit. A lot of that gear shows you how far we’ve come in less than a century. [Jeff Tranter’s] YouTube channel is a great way to look at a lot of old Heathkit gear, including this really interesting “direct reading capacity meter.” You can see the video, below.

Measuring capacitance these days is easy. Many digital multimeters have that function. However, those didn’t exist in the 1950s–at least, not in the way we know them. The CM-1 weighed 5 pounds, had several tubes, and cost what would equate to $250 in today’s prices. Unlike other instruments of the day, though, the capacitance was read directly off a large analog meter (hence, the name). You didn’t have to interpret readings using a nomograph or move a knob to balance a bridge and read the knob’s position.

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Raspberry Pi Hitches Ride Inside Vintage Terminal

March 13, 2017 by 41 Comments

When a dumpster dive yielded a vintage video display terminal, [dennis1a4] knew just what to do — bring the Heathkit H19 back to life and stuff a Raspberry Pi inside.

The early days of the personal computer era were a time of great market diversity. Everyone was making stuff needed to cobble together your perfect computer, and terminals were among the most important pieces of gear. Lear Siegler, DEC, Wyse — everyone was in on the game. Even Heathkit competed with its H19 serial terminal, which would have set you back a thousand or so early-1980s dollars.

The terminal [dennis1a4] found was DOA, but he quickly determined that a bad cap was shorting out the -12VDC rail. A little extra detective work was needed to get the terminal to both echo characters locally and output them over the RS-232 port, and bam, working terminal. But then what? Raspberry Pi to the rescue! But those old school +/-12 volts swings would give a Pi a bad case of Blue Smoke Disease. After a little voltmeter poking, and through the magic of socketed driver chips, the Pi was talking right to the terminal at a screaming 9600 baud and accessing the Hackaday Retro site on the 80-by-24 mono display.

All in all, a nice hack on a piece of computer history. But just one question: Can it play Doom Flappy Bird?

Decimal Oscilloclock Harks Back To 1927 Movie

February 21, 2017 by 25 Comments

Metropolis is a classic, silent film produced in 1927 and was one of the very first full length feature films of the science fiction genre, and very influential. (C-3PO was inspired by Maria, the “Machine human” in Metropolis.) Within the first couple of minutes in the film, we get to see two clocks — one with a 24-hour dial and another larger one with a 10-hour dial. The human overlords of Metropolis lived a utopian 24 hour day, while the worker scum who were forced to live and work underground, were subjected to work in two ten-hour shifts during the same period.

[Aaron]’s client was setting up a Metropolis themed man-cave and commissioned him to build a Metropolis Oscilloclock which would not only show the 24 hour and 10 hour clocks from the film, but also accurately reproduce the clock movements and its fonts. [Aaron]’s Oscilloclock is his latest project in the series of bespoke CRT clocks which he has been building since he was a teen.

The clock is built around a Toshiba ST-1248D vintage oscilloscope that has been beautifully restored. There are some modern additions – such as LED glow indicators for the various valves and an external X-Y input to allow rendering Lissajous figures on the CRT. He’s also added some animations derived from the original poster of the film. Doing a project of this magnitude is not trivial and its taken him almost eight months to bring it from concept to reality. We recommend looking through some of his other blog posts too, where he describes how oscilloclocks work, how he builds the HV power supplies needed to drive the CRT’s, and how he ensures vibration and noise damping for the cooling fans used for the HV power supplies. It’s this attention to detail which results in such well-built clocks. Check out some of [Aaron]’s other awesome Oscilloclock builds that we have featured over the years.

The film itself has undergone several restoration attempts, with most of it being recovered from prints which were discovered in old archives. If you wish to go down that rabbit hole, check out Wikipedia for more details and then head over to YouTube where several versions appear to be hosted.

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Heathkit: Getting Closer This Time?

November 21, 2016 by 81 Comments

We’ve been following the Heathkit reboot for a while now, and it looks like the storied brand is finally getting a little closer to its glory days. I was thumbing through the new issue of QST magazine while I was listening in on a teleconference for the day job – hey, a guy can multitask, can’t he? – when I spied an ad for the Heathkit GC-1006 digital clock, which they brand the “Most Reliable Clock”. As soon as the meeting was over, I headed over to the Heathkit website to check out this latest offering.

I had cautiously high hopes. After the ridiculous, feature-poor, no-solder AM radio kit (although they sensibly followed up with a solder version of that kit) and an overpriced 2-meter ham antenna, I figured there was nowhere for Heathkit to go but up. And the fact that the new kit was a clock was encouraging. I have fond memories of Heathkit clocks from the 80s when I worked in a public service dispatch center; Heathkit clocks were about the only clocks you could get that would display 24-hour time. Could this actually be a kit worth building?

Alas, the advertisement was another one of those wall-of-text things that the new Heathkit seems so enamored of. And like the previous two kits offered, the ad copy is full of superlatives and cutesy little phrases that really turn me off. Then again, most advertising turns me off, so I’m probably not a good gauge of such things. Nor am I sure I’m in the target demographic for this product – in fact, I’m not even sure to whom this product is being marketed. Is it the younger crowd of the maker movement? Or is it the old-timers who want to relive the glory days of Heathkit builds? Given the $100 price, I’d have to say the nostalgia market is the most likely buyer of this one.

To be fair, $100 might not be that much to spend on a decent clock. I’m a bit of a clock snob, and I’ve gotten to the point where I can almost tell which chip is in a clock just by looking at the controls. The feature set of a modern digital clock has converged to a point where every clock has almost exactly the same deficiencies. The GC-1006 claims to address a few of my hot button issues, like not being able to set the time to the exact second – I hate that! An auto-dimming display is nice, as is a 12- or 24-hour display, a 10-minute timer (nice for hams, who are required to ID their station every 10 minutes), and a battery backup that claims to last for 4 weeks.

Is this worth buying? At this point, I’m on the fence. Looking at an unboxing video, it appears to be a high-quality kit, and it would be fun to build. But spending $100 on a clock might be a tough sell to my loan officer.

Still, I think I might take one for the team here so we have a first-hand report of what the new Heathkit is all about. And it would be nice to build another Heathkit product. I’ll let you know how it goes.

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Building Better Tube Amps With Heathkit Parts

August 29, 2016 by 14 Comments

[Justin] had been trying to find a good tube amp for years, but all the best examples were either expensive or a complete basket case. Instead of buying a vintage stereo tube amp, he decided to build his own using the guts of a Heathkit AA-100, a popular tube amp from the 60s and 70s that doesn’t have a great reputation for sound quality.

This project was based on an earlier project from a decade ago that replicated the very popular Dynaco ST-70 tube amp from parts taken from the Heathkit AA-100. The schematic for this conversion was readily available on the usual tube head message boards, and a few PCBs were available for the input stage.

With the schematic in hand, the next thing for [Justin] to do was get a nice enclosure. High quality tube amps are valued as much for their appearance as they are for their sound quality, and after giving his father-in-law a few sketches, a cherry hardwood chassis stained in a beautiful golden brown appeared on [Justin]’s workbench.

The big iron for this new tube amp was taken directly from the old Heathkit, and a few hours in front of a mill netted [Justin] a chassis panel drilled out for the transformers and tube sockets. The rest of the project was a bit of assembly, point-to-point wiring, and wire management giving [Justin] a fantastic amplifier that will last for another fifty years until someone decides to reuse the transformers.