Fixing An Elgato HD60 S HDMI Capture Device

September 20, 2024 by Maya Posch 2 Comments

There’s a special kind of satisfaction found in the act of repairing a previously broken device, which is why YouTube is full of repair channels and guides on how to do it yourself. Inspired by this, [Doug Brown] decided to give it a shot himself, with an Elgato HD60 S HDMI capture device as the patient. As per the eBay listing, the device did not show up as a USB device when connected to a computer — a quick probing of the innards revealed that not only were the board voltages being dragged down, but some of the components on the PCB were getting suspiciously hot.

One of the broken switching regulators on the Elgato HD60 S capture device PCB. (Credit: Doug Brown)

On a thermal camera the hot components in question turned out to part of the voltage regulator circuits, one a switching regulator (marked fiVJVE, for Fitipower FP6373A) and another a voltage inverter marked PFNI (Ti TPS60403DBV).

Since both took 5 V, the suspicion was an over-voltage event on the USB side. After replacing the FP6373A and TPS60403 with newly purchased ones, the voltage rails were indeed healthy, and the Elgato sprung to life and could be used for HDMI capture and pass-through. However, the device’s onboard LEDs stubbornly refused to follow the boot-up pattern or show any other color patterns. Was this just a busted Innotech IT1504 LED driver IC?

Swapping it with a pin-compatible Macroblock MB15040 didn’t improve the situation, and the LEDs worked fine when externally controlling the MB15040 on its SPI bus, as well as with the original IT1504. Asking Elgato whether there was a known issue with these status LEDs didn’t lead to anything, so [Doug] decided to tackle the presumed source of the problem: the Nuvoton M031LD2AE MCU that’s supposed to drive the LED driver IC. The PCB helpfully provides a 4-pin JST connector on the board for the MCU’s SWD interface, but Elgato did protect the flash contents, so a straight dump wasn’t going to work.

The binary firmware is however helpfully available from Elgato, with the MCU already running the latest version. This is the point where [Doug] loaded the firmware into Ghidra to begin to understand what exactly this firmware was supposed to be doing. Putting on a fresh MCU with the correct firmware definitely worked, but debugging was hard as the new MCU also enabled protections, so in Ghidra the offending code for this was identified and neutralized, finally allowing for on-chip debugging and leading down another rabbit hole only to find an SPI flash chip at the end.

Ultimately it turned out that all the hardware was working fine. The problem ended up being that the LED patterns stored on the SPI EEPROM had become corrupted, which caused the Nuvoton MCU to skip over them. The same issue was confirmed on a second HD60 S, which makes it seem that this is a common issue with these Elgato capture devices. As a next step [Doug] hopes to figure out a way to more easily fix this issue, as even the streamlined process is still quite convoluted. Whether it is an issue with Elgato’s software or firmware (updater) is unknown at this point, but at least there seems to be a fix for now, even if Elgato support seems to just tell owners to ‘ignore it if capturing works’.

There’s nothing quite as inspirational as reading about a successful repair. If you need another shot of endorphins, check out the work [BuyItFixIt] put into a video baby monitor to bring it back online.

Slim Tactile Switches Save Classic TI Calculator With A Bad Keypad

September 10, 2024 by Dan Maloney 16 Comments

For vintage calculator fans, nothing strikes more fear than knowing that someday their precious and irreplaceable daily driver will become a museum piece to be looked at and admired — but never touched again. More often than not, the failure mode will be the keypad.

In an effort to recover from the inevitable, at least for 70s vintage TI calculators, [George] has come up with these nice replacement keypad PCBs. The original membrane switches on these calculators have a limited life, but luckily there are ultra-slim SMD tactile switches these days make a dandy substitute. [George] specifies a 0.8 mm thick switch that when mounted on a 1.6 mm thick PCB comes in just a hair over the original keypad’s 2.2 mm thickness. He has layouts for a TI-45, which should also fit a TI-30, and one for the larger keypads on TI-58s and TI-59s.

While these particular calculators might not in your collection, [George]’s goal is to create an open source collection of replacement keypads for all the vintage calculators sitting in desk drawers out there. And not just keypads, but battery packs, too.

Repairing A Hallicrafters S-120

September 8, 2024 by Al Williams 2 Comments

[MIKROWAVE1] claims he’s not a radio repair guy, but he agreed to look at a malfunctioning Hallicrafters S-120 shortwave receiver. He lets us watch as he tries to get it in shape in the video below. You’ll see that one of his subscribers had done a great job restoring the radio, but it just didn’t work well.

Everything looked great including the restored parts, so it was a mystery why things wouldn’t work. However, every voltage measured was about 20V too low. Turns out that the series fuse resistor had changed value and was dropping too much voltage.

Continue reading “Repairing A Hallicrafters S-120” →

How Hot Is That Soldering Iron?

September 7, 2024 by Al Williams 8 Comments

It is common these days to have a soldering iron where you can set the temperature using some sort of digital control. But how accurate is it? Probably pretty accurate, but [TheHWCave] picked up a vintage instrument on eBay that was made to read soldering iron temperature. You can see the video below, which includes an underwhelming teardown.

The device is a J thermocouple and a decidedly vintage analog meter. What’s inside? Nearly nothing. So why did the meter not read correctly? And where is the cold junction compensation?

Continue reading “How Hot Is That Soldering Iron?” →

Video Baby Monitor Repair Uncovers Private Data

September 2, 2024 by Tom Nardi 37 Comments

As the name of the channel implies, [BuyItFixIt] likes to pick up cheap gadgets that are listed as broken and try to repair them. It’s a pastime we imagine many Hackaday readers can appreciate, because even if you can’t get a particular device working, you’re sure to at least learn something useful along the way.

But after recently tackling a VTech video baby monitor from eBay, [BuyItFixIt] manages to do both. He starts by opening up the device and going through some general electronics troubleshooting steps. The basics are very much worth following along with if you’ve ever wondered how to approach a repair when you don’t know what the problem is. He checks voltages, makes sure various components are in spec, determines if the chips are talking to each other with the oscilloscope, and even pulls out the thermal camera to see if anything is heating up. But nothing seems out of the ordinary.

While poking around with the oscilloscope, however, he did notice what looked like the output of a serial debug port. Sure enough, when connected to a USB serial adapter, the camera’s embedded Linux operating system started dumping status messages into the terminal. But before it got too far along in the boot process, it crashed with a file I/O error — which explains why the hardware all seemed to check out fine.

Now that [BuyItFixIt] knew it was a software issue, he started using the tools built into the camera’s bootloader to explore the contents of the device’s flash chip. He uncovered the usual embedded Linux directories, but when he peeked into one of the partitions labeled Vtech_data2, he got a bit of a shock: the device seemed to be holding dozens of videos. This is particularly surprising considering the camera is designed to stream video to the parent unit, and the fact that it could record video internally was never mentioned in the documentation.

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Comparing AliExpress Vs LCSC-Sourced MOSFETs

August 24, 2024 by Maya Posch 26 Comments

The fake AliExpress-sourced IRFP460 MOSFETs (Credit: Learn Electronics Repair, YouTube)

These days, it’s super-easy to jump onto the World Wide Web to find purported replacement parts using nothing but the part identifier, whether it’s from a reputable source like Digikey or Mouser or from more general digital fleamarkets like eBay and AliExpress. It’s hardly a secret that many of the parts you can buy online via fleamarkets are not genuine. That is, the printed details on the package do not match the actual die inside. After AliExpress-sourced MOSFETs blew in a power supply repair by [Learn Electronics Repair], he first tried to give the MOSFETs the benefit of the doubt. Using an incandescent lightbulb as a current limiter, he analyzed the entire PSU circuit before putting the blame on the MOSFETs (IRFP460) and ordering new ones from LCSC.

Buying from a distributor instead of a marketplace means you can be sure the parts are from the manufacturer. This means that when a part says it is a MOSFET with specific parameters, it almost certainly is. A quick component tester session showed the gate threshold of the LCSC-sourced MOSFETs to be around 3.36V, while that of the AliExpress ‘IRFP460’ parts was a hair above 1.8V, giving a solid clue that whatever is inside the AliExpress-sourced MOSFETs is not what the package says it should be.

Unsurprisingly, after fitting the PSU with the two LCSC-sourced MOSFETs, there was no more magic smoke, and the PSU now works. The lesson here is to be careful buying parts of unknown provenance unless you like magic smoke and chasing weird bugs.

Continue reading “Comparing AliExpress Vs LCSC-Sourced MOSFETs” →

Unusual Tool Gets An Unusual Repair

August 15, 2024 by Dan Maloney 25 Comments

In today’s value-engineered world, getting a decade of service out of a cordless tool is pretty impressive. By that point you’ve probably gotten your original investment back, and if the tool gives up the ghost, well, that’s what the e-waste bin is for. Not everyone likes to give up so easily, though, which results in clever repairs like the one that brought this cordless driver back to life.

The Black & Decker “Gyrodriver,” an interesting tool that is controlled with a twist of the wrist rather than the push of a button, worked well for [Petteri Aimonen] right up until the main planetary gear train started slipping thanks to stripped teeth on the plastic ring gear. Careful measurements of one of the planetary gears to determine parameters like the pitch and pressure angle of the teeth, along with the tooth count on both the planet gear and the stripped ring.

Here, most of us would have just 3D printed a replacement ring gear, but [Petteri] went a different way. He mentally rolled the ring gear out, envisioning it as a rack gear. To fabricate it, he simply ran a 60° V-bit across a sheet of steel plate, creating 56 parallel grooves with the correct pitch. Wrapping the grooved sheet around a round form created the ring gear while simultaneously closing the angle between teeth enough to match the measured 55° tooth angle in the original. [Petteri] says he soldered the two ends together to form the ring; it looks more like a weld in the photos, but whatever it was, the driver worked well after the old plastic teeth were milled out and the new ring gear was glued in place.

We think this is a really clever way to make gears, which seems like it would work well for both internal and external teeth. There are other ways to do it, of course, but this is one tip we’ll file away for a rainy day.