Vintage Instrument Gets Modern Replacement For Unobtainium Parts

One of the best parts about Hackaday is how much you learn from the projects that people tackle, especially when they are repairs on old gear with unknown failure modes and potentially multiple problems. By the same token, the worst part about Hackaday is seeing what other people are capable of and knowing that you’ve got a long way to go to catch up to them.

A case in point is [Curious Marc]’s recent repair of an old pulse generator. The instrument in question is an H-P 8082A, a device from a time when H-P was a place where “good engineers managed by even better engineers [wanted] to help other engineers,” as [Marc] so eloquently puts it. The instrument was capable of 250 MHz output with complete control over the amplitude, frequency, duty cycle, and rising and falling edge geometry of the pulses, in addition to being able to output double pulses. For an all-analog instrument made in 1974, it was in decent shape, and it still powered up and produced at least the square wave output. But [Marc]’s exploration revealed a few problems, which are detailed and partially addressed in the first video below.

In part two [Marc] goes after the problem behind the pulse delay function. He traced it to a bad IC, which was bad news since it was a custom H-P part using emitter-coupled logic (ECL) to achieve the needed performance that can no longer be sourced. So naturally, [Marc] decided to replace the chip with a custom circuit. The design and simulation of the circuit are detailed in part two, while the non-trivial details of designing a PCB to handle the high-speed signals take up most of part three. We found the details on getting the trace impedance just right fascinating.

In the end, [Marc]’s pulse generator was salvaged. It’ll go into service helping him probe the mysteries of vintage electronics from the Apollo era, so we’re looking forward to seeing more about this great old instrument.

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Vintage Terminal Converted For Galactic Use In Time For May The Fourth

“Not as clumsy or random as Windows. An elegant terminal, for a more civilized age.” [Ben Kenobi] might well have said that about the Hewlett-Packard 264x-series of serial terminals, in use starting at just about the time the original installment of the Star Wars franchise was released.  With their wide-screen CRTs and toaster-oven aesthetic, they were oddballs in the terminal market, and [CuriousMarc] has gone and made one even odder by converting an H-P 2645A to display the Aurebesh character set from the movies.

A look under the hood of this lovely bit of retrocomputing history makes one think the designers almost foresaw the need to add support for a made-up language nearly half a century later. The terminal has a backplane and bus for pluggable cards, one of which carries the ROMs that [Marc] extracted and reprogrammed with the Aurebesh characters. He had a little trouble at first, needing to bodge the chip select and forgetting that he had made other “special modifications” to the terminal. The video below shows the results, along with some fatherly mortification of his daughters and a suitable tribute to the lately late [Peter Mayhew], he who donned the Wookiee suit and made a seven-foot space Sasquatch lovable.

Need more for you “May the Fourth” fix? How about a clumsy and random blaster, a cosplay speeder bike, or a fleet of droids?

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Faded Beauty DMM Gets An OLED Makeover

When a fine piece of lab instrumentation crosses your bench, you’ve got to do your best to put it to work. But even in the highest quality devices no component lasts forever, especially vacuum tubes. For some vintage instruments with vacuum fluorescent displays, that means putting up with less-than-perfect digits in order to get that sweet, sweet precision. Or not – you can always reverse engineer the thing and add a spanking new OLED display.

The Hewlett-Packard 34401A digital multimeter that fell into [qu1ck]’s lap was a beauty, but it had clearly seen better days. The display was full of spuriously illuminated dots and segments, making it hard to use the 6.5 digit DMM. After a futile bit of probing to see if a relatively easy driver fix would help, and with a replacement display being made of solid unobtanium, [qu1ck] settled in for the long process of reverse engineering the front panel protocol. As luck would have it, H-P used the SPI protocol to talk to the display, and it wasn’t long before [qu1ck] had a decent prototype working. The final version is much more polished, with a display sized to fit inside the original space occupied by the VFD. The original digits and annunciator icons are recreated, and he added a USB port and the bargraph display show in the clip below.

We think it looks fabulous, and both the firmware and hardware are on Github if you’d like to rescue a similar meter. You may want to check our guide to buying old test gear first, though, to get the most bang for your buck.

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Old Logic Analyzer Becomes New PC Case

There are a lot of cool ways to wrap a case around your custom PC build. But the off-the-shelf stuff doesn’t really set your machine apart from the herd, no matter how many RGB LEDs you put inside. If you really want to stand out, think out of the box, and build your PC into the case of an old logic analyzer.

Looking for a little retro cool factor, [Bob Alexander] turned to the world’s boneyard, eBay, and rounded up a dead H-P 1653 logic analyzer. State of the art in 1989 but not worth repairing by [Bob]’s lights, so he proceeded to remove the original 10″ CRT to make room for an alternate display. After a bit of experimentation, he settled on an LCD panel mounted behind a sheet of acrylic that he thermoformed to the shape of the CRT face. All the original guts were removed to make way for the motherboard and power supply, and a custom PCB to interface the original keypad and rotary encoder into the PC. The old buttons now launch various programs and the encoder acts as the PC volume control. The floppy drive made way for a USB hub, the BNC connectors became power and reset buttons, and a photo taken through the CRT bezel before the electronics were removed provides a window into the soul of the original instrument. It’s a really nice build, and totally unique.

Need some inspiration for your custom case mod? This wall-mounted render farm is pretty snazzy. Or perhaps you’d prefer something more apocalyptic, like this ammo can PC.