Do Not Attempt Disassembly: Analog Wizardry In A 1960s Counter

June 12, 2023 by Jonathan Bennett 22 Comments

[CuriousMarc] is back with more vintage HP hardware repair. This time it’s the HP 5245L, a digital nixie-display frequency counter from 1963. This unit is old enough to be entirely made of discrete components, but has a real trick up its sleeve, with add-on components pushing the frequency range all the way up to 18 GHz. But this poor machine was in rough shape. There were previous repair attempts, some of which had to be re-fixed with proper components. When it hit [Marc]’s shop, the oscillator was working, as well as the frequency divider, but the device wasn’t counting, and the reference frequencies weren’t testing good at the front of the machine. There were some of the usual suspects, like blown transistors. But things got really interesting when one of the boards had a couple of tarnished transistors, and a handful of nice shiny new ones — but maybe not all the right transistors. Continue reading “Do Not Attempt Disassembly: Analog Wizardry In A 1960s Counter” →

Hackaday Links: May 28, 2023

May 28, 2023 by Dan Maloney 20 Comments

The Great Automotive AM Radio War of 2023 rages on, with the news this week that Ford has capitulated, at least for now. You’ll recall that the opening salvo came when the US automaker declared that AM radio was unusable in their EV offerings thanks to interference generated by the motor controller. Rather than fixing the root problem, Ford decided to delete the AM option from their EV infotainment systems, while letting their rolling EMI generators just keep blasting out interference for everyone to enjoy. Lawmakers began rattling their sabers in response, threatening legislation to include AM radio in every vehicle as a matter of public safety. Ford saw the writing on the wall and reversed course, saying that AM is back for at least the 2024 model year, and that vehicles already delivered without it will get a fix via software update.

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Hackaday Links: March 12, 2023

March 12, 2023 by Dan Maloney 38 Comments

With a long history of nearly universal hate for their products, you’d think printer manufacturers would by now have found ways to back off from the policies that only seem to keep aggravating customers. But rather than make it a financially wiser decision to throw out a printer and buy a new one than to buy new ink cartridges or toners, manufacturers keep coming up with new and devious ways to piss customers off. Case in point: Hewlett-Packard now seems to be bricking printers with third-party ink cartridges. Reports from users say that a new error message has popped up on screens of printers with non-HP cartridges installed warning that further use of the printer has been blocked. Previously, printers just warned about potential quality issues from non-HP consumables, but now they’re essentially bricked until you cough up the money for legit HP cartridges. Users who have contacted HP support say that they were told the change occurred because of a recent firmware update sent to the printer, so that’s comforting.

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Classic Calculators Emulated In Browser

January 30, 2023 by Bryan Cockfield 24 Comments

The Multiple Arcade Machine Emulator, now known simply as MAME, started off as a project to emulate various arcade games. The project is still adding new games to its library, but the framework around MAME makes it capable of emulating pretty much any older computer. The computer doesn’t even need to be a gaming-specific machine as the latest batch of retro hardware they’ve added support for is a number of calculators from the 90s and early 00s including a few classics from Texas Instruments.

Since no one is likely to build an arcade cabinet version of a TI-89, all of these retro calculators are instead emulated entirely within a browser. This includes working buttons and functions on an overlay of each of these calculators but also pixel-accurate screen outputs for each of these. The graphing calculators have more of what we would consider a standard computer screen, but even the unique LCDs of some of the more esoteric calculators are accurately replicated as well thanks to the MAME artwork system.

There are a number of calculators implemented under this project with a full list found at this page, and the MAME team has plans to implement more in the future. If you’re looking for something fun to do on a more modern calculator, though, take a look at this build which implements ray tracing on a TI-84 Plus CE.

Thanks to [J. Peterson] for the tip!

Fixing An HP 54542C With An FPGA And VGA Display

January 13, 2023 by Maya Posch 11 Comments

Although the HP 54542C oscilloscope and its siblings are getting on in years, they’re still very useful today. Unfortunately, as some of the first oscilloscopes to switch from a CRT display to an LCD they are starting to suffer from degradation. This has led to otherwise perfectly functional examples being discarded or sold for cheap, when all they need is just an LCD swap. This is what happened to [Alexander Huemer] with an eBay-bought 54542C.

Although this was supposed to be a fully working unit, upon receiving it, the display just showed a bright white instead of the more oscilloscope-like picture. A short while later [Alexander] was left with a refund, an apology from the seller and an HP 54542C scope with a very dead LCD. This was when he stumbled over a similar repair by [Adil Malik], right here on Hackaday. The fix? Replace the LCD with an FPGA and VGA-input capable LCD.

While this may seem counter intuitive, the problem with LCD replacements is the lack of standardization. Finding an 8″, 640×480, 60 Hz color LCD with a compatible interface as the one found in this HP scope usually gets you salvaged LCDs from HP scopes, which as [Alexander] discovered can run up to $350 and beyond for second-hand ones. But it turns out that similar 8″ LCDs are found everywhere for use as portable displays, all they need is a VGA input.

Taking [Adil]’s project as the inspiration, [Alexander] used an UPduino v3.1 with ICE40UP5K FPGA as the core LCD-to-VGA translation component, creating a custom PCB for the voltage level translations and connectors. One cool aspect of the whole system is that it is fully reversible, with all of the original wiring on the scope and new LCD side left intact. One niggle was that the scope’s image was upside-down, but this was fixed by putting the new LCD upside-down as well.

After swapping the original cooling fan with a better one, this old HP 545452C is now [Alexander]’s daily scope.

A Modern Tribute To The Classic HP-16C Calculator

December 21, 2022 by Lewin Day 19 Comments

The HP-16C Computer Scientist is much beloved as the only dedicated programmer’s calculator that Hewlett-Packard ever made. Most surviving examples in the world are well-used, and you haven’t been able to order one from HP since 1989. Thus, [K Johansen] set about building a tribute to the HP-16C using modern hardware.

The build relies on a Raspberry Pi Pico as the brains of the operation. As with so many classic HP calculators, it operates in Reverse Polish Notation, and includes the customary stack operations. To serve a programmer well, it’s set up to accept entry in hexadecimal, octal, decimal, and binary formats, and can readily convert between them. Beyond that, it’s equipped with the usual arithmetic operators, as well as bitwise operations like NOT, AND, and so on.

Perhaps what we love most, though, is the keypad. It was all put together with a combination of cheap AliExpress keypads, a label maker, and a laser printer. It’s a wholly DIY job, and a little rough around the edges, but it makes the calculator far easier to use.

It’s not an exact replica of the HP-16C, but the differences in operation are minor.Those wishing to build their own can grab the required files from the project’s Github page. We’ve seen replicas of other classic HP calculators before, too. If you’ve got your own mathematical projects brewing up in the lab, don’t hesitate to send them in to the tipsline!

Frequency Counter Restoration Impeded By Kittens

August 24, 2022 by Al Williams 12 Comments

We think of digital displays as something you see on relatively modern gear. But some old gear had things like nixies or numitrons to get cool-looking retro digital displays. The HP 521A frequency counter, though, uses four columns of ten discrete neon bulbs to make a decidedly low-tech but effective digital display. [Usagi Electric] has been restoring one of these for some time, but there was a gap between the second and third videos as his workshop became a kitten nursery. You can see the last video below.

In previous videos, he had most of the device working, but there were still some odd behavior. This video shows the final steps to success. One thing that was interesting is that since each of the four columns are identical, it was possible to compare readings from one decade to another.

However, in the end, it turned out that the neon bulbs were highly corroded, and replacing all the neon bulbs made things work better. However, the self-check that should read the 60 Hz line frequency was reading 72 Hz, so it needed a realignment. But that was relatively easy with a pot accessible from the back panel. If you want to see more details about the repair, be sure to check out the earlier videos.

We love this old gear and how clever designers did so much with what we consider so little. We hate to encourage your potential addiction, but we’ve given advice on how to acquire old gear before. If you want to see what was possible before WS2812 panels, you could build this neon bulb contraption.

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