Resurrecting An Electric Razor

[Salvatore Ventura] likes a close shave from an electric razor, and nothing shaves closer than a new set of blades. After shelling out for some sharp ones, the rechargeable batteries died so he set out to replace them with a couple of double A’s (not the ones pictured above as those are alkaline).

This fix actually increased the original battery life of the razor by about 30%. That’s thanks to a larger capacity than the battery that had come with the razor. But [Salvatore] didn’t get to enjoy the windfall for very long. One morning the charge light was blinking on the razor and it wouldn’t spin up at all. After testing the batteries with a multimeter he found that they had a full charge and figured it was the main board that had gone out.

The real question is, what is that board actually doing? A bit of study led him to the conclusion that it is just a charging circuit, and an on/off switch. He kissed the board goodbye, wired up the AA battery holders directly. Now he jams a paper clip into the recharging jack, shorting the pins to complete the circuit. He could even keep using rechargeables with an external charger if he was careful not to run them too low.

Who Knew Thinkpad Batteries Require A Jump Start?

Lithium battery packs reaching the end of their life usually have a lot of kick left in them. That’s because they’re made up of multiple cells and it only takes the failure of one to bork the entire battery. One of the most interesting examples we’ve heard of this is in the Toyota Prius, but that’s a story for another time. In this case, [Mika] wanted to resurrect the battery from his IBM Thinkpad T40. He identified the offending cell and replaced it, but couldn’t get any juice out of the battery after the repair.

He was measuring 0V on the output, but could measure the cells instead of the control circuitry and was getting over 11V. Clearly, the control circuit wasn’t allowing an output. We completely understand the concept here (think about that really bad press about exploding laptop batteries). It seems there’s a lockout mechanism when the control circuit loses power. [Mika] managed to get past this by shorting voltage into the control circuit, a method he likes in the video after the break to jump starting a car.

We’ve seen similar cell replacement for power tools, like a Dremel or a Makita drill.

Continue reading “Who Knew Thinkpad Batteries Require A Jump Start?”

Power Tool Battery Charger Repair

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[Webby] inherited a cordless drill from his dad and when he finally got around to using it, found that the charger was dead in the water. He disassembled it and narrowed the issue down to the charger’s primary transformer, but didn’t know where to go from there. A friend suggested that the coil’s thermal fuse might have blown, and upon further investigation, [Webby] discovered that his friend was right.

He removed the dead fuse and soldered in a piece of wire just for testing – not surprisingly the charger sprang to life. He picked up a new thermal fuse to replace the old one, but he wasn’t quite satisfied with the fix just yet. If the fuse burned out once already, there’s little to stop it from happening again, so he decided that installing a small cooling fan would be a good idea. He mounted the fan on the outside of the case after cutting some vent holes, leeching power from the charger itself.

While simply adding a fan to the charger might not be everyone’s idea of a perfect solution, it has worked out quite well for [Webby] in the past, so if it isn’t broken…

[via HackedGadgets]

Bypassing Manufacturer-imposed Battery Lockouts

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When [Barret] went to use his camera the other day it kept shutting down on him, and upon inspecting the battery, he found that it was a bit swollen. Knowing that he needed a replacement, he turned to an aftermarket battery he had sitting around, but grew pretty annoyed when his Sony Cybershot camera would not accept it.

Apparently a recent firmware update causes his camera to reject non-Sony batteries, a situation he describes as “battery DRM”. There was no way he was going to pony up another $50 to Sony instead of using the perfectly good $10 battery he already had, so he decided to rectify the issue himself.

He stripped both batteries of their plastic coatings, revealing the lithium cells and their charging circuits. He desoldered the PCB from his Sony battery, transplanting it to his aftermarket battery after a little bit of trimming. He wrapped everything up with some tape and gave his franken-battery a spin. It worked a treat, and he was so satisfied with it that he did a similar swap in his aging Logitech mouse.

As more and more companies lock competitors out of the user-replaceable consumables market, these sorts of hacks are certain to become more and more prevalent.

Replacing Non-standard USB Charging Ports

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While many mobile phone manufacturers are moving towards the micro-USB interface as a standard, others such as Apple and HTC are still bucking the trend. Part of [arto’s] job includes repairing mobile phones, and last month he found himself faced with a pair of broken HTC handsets that needed their charging ports replaced.

Replacements for HTC’s proprietary connectors are apparently quite hard to find, and [arto] says he had to source them from an HTC repair center. With the proper parts in hand, he could finally get down to work.

The HTC Hermes handset he repaired was a breeze, as it had plenty of space available around the charging port. He said that this allowed him to replace the jack pretty easily, but the HTC Touch Dual was a mess in comparison. He started by removing the old adapter, which was done by cutting it out bit by bit. He says that he did it this way rather than desoldering, due to its proximity to other heat-sensitive components. After some careful soldering under a microscope, everything was back in working order.

While his repairs are not necessarily the things that hacks are made of, the information is still quite helpful. Broken charging ports are extremely common among smart phones, and with plenty of these older models still floating around, his pointers just might help someone save a few bucks on a replacement phone.

Repairing A Broken Salad Spinner

Behold [Quinn’s] broken salad spinner, and just when lettuce and other garden produce are hitting their peak. We were surprised to find out that she was able to get the mechanism apart to fix the broken cord. We’re sick and tired of ultrasonically welded plastic enclosures that lock out the most well-intentioned repairman. But in [Quinn’s] case there were a few plastic plugs hiding the screws that keep the two pieces of the case together.

After diagnosing that the cause of the broken cord was a gnarly metal grommet, she removed the offender and sought a replacement cord. The first material she tried was some dental floss but unsurprisingly it only lasted through a few spins. Next on the road to repair was a shoelace which did a bit better but also ended up broken. But the discovery of some parachute cord did the trick in the end and now it’s good as new if not better!

DIY Battery Reconditioner Saves Old Rechargeable Batteries From The Landfill

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Instructables user [msuzuki777] had amassed quite a collection of batteries over the years, but was finding that some of his rechargeable AA and AAA cells seemed to be at the end of their useful life. After reading some information at the Battery University regarding the restoration process for nickel-based batteries, he figured he might as well try building a battery reconditioner of his own.

He worked through several designs that either flat-out did not work, or had issues that limited the number of batteries he could simultaneously recondition. After reading about this rechargeable battery capacity tester we featured a few months back, he was ready to give the project one more try.

It seems that the third try was the charm, because his FET-based design worked quite well. He ended up wiring two FETs to each battery, which are connected via a relay. The batteries get discharged until the voltage drops down to 1V, at which point one FET is turned off, allowing the batteries reach their target voltage of 0.4V more slowly.

Despite the self-proclaimed messy layout of his circuit, [msuzuki777] is quite happy with the results. He has been able to recover several batteries, which is a fantastic alternative to letting them decay in a landfill.