Repairing An HDMI Adapter Doesn’t Go So Well

[Adrian] has a lot of retrocomputers, so he uses an RGB to HDMI converter to drive modern monitors. In particular, he has a box that uses a programmable logic chip to read various RGB signals and ships them to a Raspberry Pi Zero to drive the HDMI output. Sounds great until, of course, something goes wrong.

A converter that had worked stopped working due to a bad board with the programmable logic chip on it. Unlike the retrocomputers, this board has little tiny surface mount components. A little analysis suggested that some of the chip pins were not accepting inputs.

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The Hair Dryer Monitor Fix

[Johnny] had a monitor that he was particularly fond of. The whole monitor appeared dead, and he decided to open it up and find out what could be wrong. He wound up fixing it — sort of — using a hairdryer. While we think his explanation of the problem is unlikely, we hate to armchair quarterback, and we applaud that he opened it up and got it working.

When something is dead, it is always a good idea to check the power and power supply, but that didn’t pan out in this case. In fact, the power supply board inside had what looked like reasonable voltage values throughout. The problem had to be something more subtle.

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Printable Fix For Time Card Clock Has Owner Seeing Red Again

When [Morley Kert] laid eyes on a working time card-punching clock, he knew he had to have it for a still-secret upcoming project. The clock seemed to work fine, except that after a dozen or so test punches, the ink was rapidly fading away into illegibility. After a brief teardown and inspection, [Morley] determined that the ribbon simply wasn’t advancing as it should.

This clock uses a ribbon cassette akin to a modern typewriter, except that instead of a feed spool and a take-up spool, it has a short length of ribbon that goes around and around, getting re-inked once per revolution.

When a card is inserted, a number of things happen: a new hole is punched on the left side, and an arm pushes the card against the ribbon, which is in turn pushed against the mechanical digit dials of the clock to stamp the card.

Finally, the ribbon gets advanced. Or it’s supposed to, anyway. [Morley] could easily see the shadow of a piece that was no longer there, a round piece with teeth with a protrusion on both faces for engaging both the time clock itself and the ribbon cassette. A simple little gear.

After emailing the company, it turns out they want $95 + tax to replace the part. [Morley] just laughed and fired up Fusion 360, having only caliper measurements and three seconds of a teardown video showing the missing part to go on. But he pulled it off, and pretty quickly, too. Version one had its problems, but 2.0 was a perfect fit, and the clock is punching evenly again. Be sure to check it out after the break.

Okay, so maybe you don’t have a time card clock to fix. But surely you’ve had to throw out an otherwise perfectly good coat because the zipper broke?

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Ask Hackaday: Repair Café Or Not?

A huge part of the work our community does, aside from making things and doing a lot of talking about the things we’d like to make, involves repair. We have the skills to fix our own stuff when it breaks, we can fix broken stuff that other people throw out when it breaks, and we can fix broken stuff belonging to other people. As our consumer society has evolved around products designed to frustrate repairs and facilitate instead the sale of new replacements for broken items this is an essential skill to keep alive; both to escape having to incessantly replace our possessions at the whim of corporate overlords, and to fight the never-ending tide of waste.

Repair Cafés: A Good Thing

A German repair cafe
A German repair café. , Redaktion NdW, CC BY 2.0

So we repair things that are broken, for example on my bench in front of me is a formerly-broken camera I’ve given a new life, on the wall in one of my hackerspaces is a large screen TV saved from a dumpster where it lay with a broken PSU, and in another hackerspace a capsule coffee machine serves drinks through a plastic manifold held together with cable ties.

We do it for ourselves, we do it within our communities, and increasingly, we do it for the wider community at large. The Repair Café movement is one of local groups who host sessions at which they repair broken items brought in by members of the public, for free. Their work encompasses almost anything you’d find in a home, from textiles and furniture to electronics, and they are an extremely good cause that should be encouraged at all costs.

For all my admiration for the Repair Café movement though, I have chosen not to involve myself in my local one. Not because they aren’t a fine bunch of people or because they don’t do an exceptionally good job, but for a different reason. And it symbolically comes back to an afternoon over thirty years ago, when sitting in a university lab in Hull, I was taught how to wire a British mains plug. Continue reading “Ask Hackaday: Repair Café Or Not?”

An HP9830A opened up and running

The Epic Journey Of Repairing An HP 9830A Desktop Computer From The 1970s

We love our retrocomputers here at Hackaday, and we’re always delighted to see someone rescue an historic artefact from the landfill. Sometimes, all it takes is replacing a broken power switch or leaky capacitor; other times you need to bring out the oscilloscope and dig deeper into internal circuitry. But the huge amount of work [Jerry Walker] put into bringing an HP 9830A back on its feet is something you don’t see very often.

If you’re not familiar with the HP 9830A, it’s a desktop computer from the early 1970s, fully built from discrete logic gates. The machine on [Jerry]’s desk turned out to be completely dead, with not even the fan spinning up. This was caused by a dodgy power switch, but replacing that switch was just the beginning: there were several bad components inside the power supply as well as a huge amount of moist dirt on the back of the motherboard. After a thorough cleaning and the replacement of several failed components, all four power rails were running within spec again.

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Fix Every Broken Via To Return This Game To Life

We all know the havoc that water in the wrong place can do to a piece of electronics, and thus we’ve probably all had devices damaged beyond repair. Should [Solderking] have thrown away the water-damaged PCB from a Nintendo Pokemon Ruby cartridge? Of course he should, but when faced with a board on which all vias had succumbed to corrosion he took the less obvious path and repaired them.

Aside from some very fine soldering in the video below the break there’s little unexpected. He removes the parts and tries a spot of reworking, but the reassembled board doesn’t boot. So he removes them again and this time sands it back to copper. There follows a repair of every single vial on the board, sticking fine wires through the holes into a sponge and soldering the top, before turning it over and fixing the forest of wires on the other side. Fixing the ROM results in a rather challenging fitment involving the chip being mounted at an angle and extra wires going to its pads, which demonstrates the value in this story. It’s not one of monetary value but of persevering with some epic rework to achieve a PCB which eventually boots. Of course a replacement board would make more sense. But that’s not the point, is it?

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Is Your Device Actually USB 3.0, Or Is The Connector Just Blue?

Discount (or even grey market) electronics can be economical ways to get a job done, but one usually pays in other ways. [Majenko] ran into this when a need to capture some HDMI video output ended up with rather less than was expected.

Faced with two similar choices of discount HDMI capture device, [Majenko] opted for the fancier-looking USB 3.0 version over the cheaper USB 2.0 version, reasoning that the higher bandwidth available to a USB 3.0 version would avoiding the kind of compression necessary to shove high resolution HDMI video over a more limited USB 2.0 connection.

The device worked fine, but [Majenko] quickly noticed compression artifacts, and interrogating the “USB 3.0” device with lsusb -t revealed it was not running at the expected speeds. A peek at the connector itself revealed a sad truth: the device wasn’t USB 3.0 at all — it didn’t even have the right number of pins!

A normal USB 3.0 connector is blue inside, and has both sets of pins for backward compatibility (five in the rear, four in the front) like the one shown here.

A USB 3.0 connection requires five conductors, and the connectors are blue in color. Backward compatibility is typically provided by including four additional conductors, as shown in the image here. The connector on [Majenko]’s “USB 3.0” HDMI capture device clearly shows it is not USB 3.0, it’s just colored blue.

Most of us are willing to deal with the occasional glitch or dud in exchange for low prices, but when something isn’t (and never could be) what it is sold as, that’s something else. [Majenko] certainly knows that as well as anyone, having picked apart a defective power bank module to uncover a pretty serious flaw.