Repairing Flex Circuits By Accident

A while ago, [drygol] was asked to repair a few old Amiga keyboards. The key switches worked fine, but in the past decade or two, the flexible PCB ribbon connector has been mistreated, and was in an unworkable, nonfunctional state. The fragile traces underneath the green epoxy coating were giving way, but [drygol] found a few cool ways to repair these flex cables.

The end of this keyboard cable was beyond repair, but the Commodore engineers were gracious enough to leave a bit of slack in this keyboard connector. After cutting off the most damaged section, [drygol] had a strip of plastic, a few copper traces, and a green coating that had to be removed. The first attempt to remove this green covering used methanol, but that didn’t work. The next chemical attempt was with an epoxy solvent that contained nasty chemicals. This was applied to the end of the flex cable, with the remainder of the cable masked off by Kapton. It worked remarkably well.

In removing the Kapton masking tape, [drygol] discovered this green film sticks better to Kapton than it does to copper and plastic. A mechanical solution was found, allowing these keyboard cables to be easily repaired.

Of course, this was only half of the problems with these flexible circuits. Over the years, a few cracks appeared in the traces. To repair these broken traces, [drygol] turned to silver glue and a few laminations of Kapton to make this keyboard cable whole again. It worked, and the ancient keyboard was returned to service. Great work, and a fantastic observation for anyone with one of these keyboards sitting around: just grab a roll of Kapton to repair these circuits. It can’t get any easier than that.

Replacing a Failed Ebook Reader Battery

Resurrecting a beloved piece of tech can be a trying process when fighting through the mild heartbreak — doubly so if the product has been discontinued. When their old Sony PRS-T1 e-book reader refused to charge after leaving it on their dashboard during a hot day, [Andrea Gangemi] decided to leverage a little techno-necromancy and hack together a fix.

[Gangemi] found the problem to be a battery failure, but there was nary a replacement to be found. An old Motorola mobile phone battery ended up fitting the purpose nicely. Cracking open the e-book reader, de-soldering the old battery and — after deciphering which pins were which — installing the new one was simply done with a fine, high temperature soldering iron tip and Kapton tape to avoid short-circuiting. But hold on — the new battery wouldn’t charge, and the reader displayed a message saying that the battery was over heating; irony, thou art cruel.

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Home-made Adjustable Knife Jig

When sharpening a knife, it is critical to have the knife at the right angle. A knife jig handles this for you, letting you focus on getting the edge right. You could just buy one, but where’s the fun in that? [origamimavin] decided to make his own adjustable knife jig using bits he bought from the hardware store for $27, and which you might have in your junk pile. Fortunately for us, he’s written up the process in excellent detail, explaining the how and why of each step.

He used a couple of tools that you might not have lying around (a bandsaw and a belt sander), but these could be easily replaced with their manual cousins, or your local hackerspace will doubtless provide you access to them. Either way, it’s a simple build which could help your knives keep their clean, sharp edge for years to come.

Restoring The Groundbreaking Xerox Alto

The Xerox Alto was a minicomputer that had a lot of firsts to its name: first GUI, first Ethernet connection, and first computer to use a laser printer. This is the computer that inspired Steve Jobs to build the Lisa. And this was built all back in 1973! So when [Ken Shirriff] and a team of other old-computer aficionados got their hands on one, you know they’d get to work.

[Ken]’s blog describes the start of what’s sure to be a long journey. It mostly describes the Alto system and locates its place in computer history, but there are some interesting sidelines as well — like how [Alan Kay] also basically outlined all of the functionality of the modern laptop / tablet along the way to the Alto; it was supposed to be an interim Dynabook.

Work on this grandfather-of-modern-computers is just getting started, and [Ken] and crew are dusting off the power supplies and cataloguing memory boards. You can be sure that we’ll follow along with this restoration project, and keep you informed.

Smartphone Hack For Adding Magnet Power Dock

Here’s a neat hack for making a magnetic charging mount for a cell phone. We know what you’re thinking, but this is definitely not a traditional contactless charging system. Those use magnets but in a different way. This hack involves putting a couple of magnets onto the case of the cell phone, and a couple more on a charging base. You then wire these magnets into the power inputs of the USB port, and a USB cable onto the base, so putting the phone on the base magnets completes the circuit. The magnets themselves become the charging contacts.

It’s a neat idea, but makes us wonder what this will do to the compass sensor in your phone or your credit cards if they are nearby. With these caveats, it is a neat hack, and could be easily adapted. Want to make a vertical cell phone mount, or a way to attach (and charge) your cell phone to the fridge? This can be easily adapted for that.

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Fixing a broken CCFL Backlight

When you work at Tektronix and they make a difficult to refuse offer for their ‘scopes, you obviously grab it. Even if the only one you can afford is the not-so-awesome TDS1012. [Jason Milldrum] got his unit before cheaper, and better ‘scopes appeared on the market. It served him well for quite a long time. But keeping it switched on all the time took a toll, and eventually the CCFL backlight failed. Here’s how he replaced the CCFL back light with a strip of LED’s and revived the instrument.

Searching for an original replacement CCFL backlight didn’t turn up anything – it had been obsoleted long back. Even his back-channel contacts in Tektronix couldn’t help him nor could he find anything on eBay. That’s when he came across a video by [Shahriar] who hosts the popular The Signal Path blog. It showed how the CCFL can be replaced by a thin strip of SMD LEDs powered by a DC-DC converter. [Jason] ordered out the parts needed, and having worked at Tektronix, knew exactly how to tear down the ‘scope. Maybe he was a bit rusty, as he ended up breaking some (non-critical) plastic tabs while removing the old CCFL. Nothing which could not be fixed with some silicone sealant.

The original DC-DC converter supplied along with his LED strip needed a 12V input, which was not available on the TDS1012. Instead of trying to hack that converter to work off 6V, he opted to order out another suitable converter instead. [Jason]’s blog details all the steps needed, peppered with lots of pictures, on how to make the swap. The one important caveat to be aware of is the effect of the LED DC-DC converter on the oscilloscope. Noise from the converter is likely to cause some performance issues, but that could be fixed by using a more expensive module with RF and EMI filtering.

This is not an original hack for sure. Here’s a “Laptop backlight converted from CCFL to LED” from a few years back, and this one for “LCD: Replacing CCFL with LEDs” from even further back in time. Hopefully if you have an instrument with a similar issue, these ought to guide you on how to fix things.

Fixing a Broken Bandsaw with a Custom Steel Part

When a large bandsaw broke down due to a cast iron part snapping in two, [Amr] took the opportunity to record the entire process of designing and creating a solid steel replacement for the broken part using a (non-CNC) mill and lathe.

For those of us unfamiliar with the process a machinist would go through to accomplish such a thing, the video is extremely educational; it can be sobering both to see how much design work happens before anything gets powered up, and just how much time and work goes into cutting and shaping some steel into what at first glance looks like a relatively uncomplicated part.

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