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.

Dead Washer Lives Again With ATTiny

January 11, 2023 by Al Williams 59 Comments

We aren’t saying that appliances are a scam, but we have noticed that when your appliances fail, there’s a good chance it will be some part you can no longer get from the appliance maker. Or in some cases, it’s a garden-variety part that should cost $2, but has been marked up to $40. When [Balakrishnan] had a failure of the timer control board for a Whirlpool washing machine, it was time to reverse engineer the board and replace it with a small microcontroller.

Of course, this kind of hack is one of those that won’t help you unless you need exactly that timer board. However, the process is generally applicable. Luckily, the motherboard chip was documented and the timer control board used a simple ATmega88, so it was easy to see that the devices were communicating via I2C.

Reading the I2C bus is easy with a logic analyzer, and this revealed the faulty device’s I2C address. The board that failed was only for display, so a simple program that does nothing other than accept I2C data put the washer in working order. Once it was working with an Arduino, an ATTiny45 did the work with a lot less space and cost.

If you don’t want to reverse engineer the washing machine, you could just replace all the controls. That even works if the old washer wasn’t electronic to start.

You Can Now Fix Your Deere

January 9, 2023 by Jenny List 29 Comments

Over the last few years we have brought you many stories about John Deere tractors, and how their repair has been locked down such that only manufacturer-authorised technicians can work on them. They’ve become a poster child in the battle for the right to repair, a symbol of the worst practices. Finally now we can bring you some good news of sorts, as the agricultural giant has signed a memorandum of understanding with the American Farm Bureau Federation to ensure that their products will henceforth be repairable by people without Deere approval.

We can’t imagine that Deere will have taken this step willingly, and while we’d like to imagine that consumer protests in favour of right-to-repair have hit their mark, we’re guessing that it’s more of an economic pressure at work alongside the threat of legislation outside their native America. If farmers getting caught out waiting for a Deere van to arrive while their crop withers in the field wasn’t enough, when the price of a second-hand tractor without the DRM outstrips that of a newer one with it, eventually the sales of new tractors will also suffer.

So this is good news, and we’re guessing that other agricultural manufacturers doing the same DMCA practices will now follow suit. But it’s not a complete victory. The problem starts not with the DMCA restriction itself, but with the extension of the machine’s computer system into every part, including those many parts which simply don’t need it. It’s not a complete victory if anyone can now use the software to register a new hydraulic valve with the system; instead that hydraulic valve should not have to be authorised in the first place. It’s this creeping unnecessary complexity which is the true enemy of right-to-repair, and we shouldn’t forget that.

Header image: Dwight Sipler, CC BY 2.0.

Ask Hackaday: What’s Your Worst Repair Win?

January 9, 2023 by Dan Maloney 191 Comments

Like many of you, I’ve become the designated “fix-it” person for my family and friends. While it can be a lot of work — I just finished an oil change that required me to lay in a cold, wet driveway and I can’t mention in polite company the substances I was bathed in while fixing a clogged pipe last week — I generally relish my role. I enjoy solving problems, I love working with my hands and my head, and who doesn’t like saving money and time?

But for me, the best part of being the fix-it guy is the satisfaction that comes from doing something others can’t do. I find this especially true with automotive repairs, which conventional wisdom says is strictly the province of factory-trained experts. A little bit of a hero complex, perhaps? Absolutely! After all, I don’t get paid for my repairs, so I’ve got to get a little something for the effort.

This is why a recent pair of unrelated fixes left me feeling thoroughly unsatisfied. Neither of these jobs was a clear win, at least in terms of getting the rush of being able to do something that nobody else could. At best, these were qualified wins, which both still left me feeling a little defeated. And that got me thinking that I’m probably not the only one who has had marginal repair wins like these.

Continue reading “Ask Hackaday: What’s Your Worst Repair Win?” →

Bypass Defective STDP9320 Video Controller On Wacom Cintiq Companion 2

January 4, 2023 by Maya Posch 8 Comments

Some products seem to have a part of two that’s pretty much guaranteed to end up dying on you. In the case of the 2015-vintage Wacom Cintiq Companion 2, this turns out to be the so-called Athena chip, which switches the display input between the HDMI port and internal display controller. This allows for use in both standalone mode (tablet), as well as companion mode, where it acts as a drawing tablet for a connected PC. When confronted with such a faulty device, [neutrino] found and applied a simple fix: bypassing the Athena chip altogether.

This fix is recommended by the Repair Preservation Group’s wiki page on the topic, noting that this will permanently disable its use as an external display without additional repairs to recreate the functionality of the removed chip. This STDP9320 (PDF) part by ST Microelectronics is described as a ‘Premium high resolution multimedia monitor controller with 3D video’ and contains a wide range of video scalers, a HDMI receiver, DisplayPort (including embedded DP) support. With this fix, the Cintiq Companion 2’s Intel CPU’s graphics core is directly connected to the display’s eDP input, along with a range of voltages and enable pins.

What the exact reason is for the STDP9320 dying after a few years with what appears to be some kind of internal power failure or short, but this bypass fix at least restores standalone functionality. Sourcing a replacement for this obsolete IC seems possible, but a big gamble. Sadly, it would seem that this Wacom device will no longer be a companion for much longer.

HP 33120A Repair: Shutting Down The Eye Of Sauron

January 3, 2023 by Maya Posch 22 Comments

When a friend of [Tom Verbeure] came into possession of two HP 33120A 15 MHz function/arbitrary waveform generators, he could not resist giving them a try. Although not exactly high-end units, the HP 33120A makes for a pretty nice unit for a home lab. During the first test run, however, [Tom] discovered that one of the units had a dead output, which made it rather useless. Undeterred, [Tom] set to work diagnosing it, helped by the repair manual and full schematics.

While the cause was quickly tracked down to the general area around an exploded MLCC, fixing the fried Zener diode that may have initiated the short on the -15V rail revealed an unpleasant surprise. To [Tom]’s horror, he saw a portal to Hell itself open when part of the PCB caught on fire due to an internal short. After making sure to capture a video of this event, he then proceeded to use a thermal camera to track down the hot spot and uses a drill to remove the short.

While one can argue with the use of a drill to remove shorts on inner layers of a PCB, ultimately the fix was effective. A look on the schematic and comparison with the functioning 33120A unit later, all it took was two bodge wires to restore functionality. After this event, [Tom]’s friend gave him the repaired unit as thanks, and definitely not because [Tom] had begun to refer to it as ‘his precious’.

Laser Cut Clips Save A Lamp From The Trash

December 25, 2022 by Jenny List 6 Comments

Ikea have been known for years as a purveyor of inexpensive yet stylish homewares, but it’s fair to say that sometimes their affordability is reflected in their insubstantial construction. Such is the case with the Sjöpenna lamp, whose construction relies on rubber bands. On [Tony]’s lamp these bands degraded with age, causing it to fall apart. The solution? A set of cleverly-designed laser-cut clips to replace them.

The challenge to replacing a stretchy material with a rigid one is that it must have enough ability to bend without snapping as it is put in place. For this he selected PETG, with 0.04″ (about 1 mm thick) hitting the sweet spot. His photos demonstrate with some green tape added for visibility, how the clip bends backwards just far enough to fit over where the rubber band once located, and then flips back neatly to hold it all in place.

If you have a collapsing Ikea lamp then this will be just what you need, but this hack goes further than that. A frequent requirement for repairs is some kind of clip, because clips are always the first to break, This technique for laser cutting them is a handy one to remember, next time your design needs a springy bit of plastic.