Lithium Jump Starter Disassembly Is Revealing

High-capacity lithium batteries tend to make everything in life better. No longer must you interact with your fellow human beings if your car battery goes flat in the carpark. You can jump the car yourself, with a compact device that fits in your glovebox. [Big Clive] decided to pull one apart and peek inside, and it’s quite the illuminating experience.

The first thing to note is there is almost no protection at all for the lithium battery inside. The output leads connect the lithium pack inside directly to the car battery, save for some diodes in series to prevent the car’s alternator backcharging the pack. [Clive] demonstrates this by short circuiting the pack, using a copper pipe as a test load to measure the current output. The pack briefly delivers 500 amps before the battery gives up the ghost, with one of the cells swelling up and releasing the magic smoke.

The teardown then continues, with [Clive] gingerly peeling back the layers of insulation around the cells, getting right down to the conductive plates inside. It’s a tough watch, but thankfully nothing explodes and [Clive]’s person remains intact. If you’ve never seen inside a lithium cell before, this is a real treat. The opened pack is even connected to a multimeter and squeezed to show the effect of the physical structure on output.

It would be interesting to compare various brands of jump starter; we imagine some have more protection than others. Regardless, be aware that many on the market won’t save you from yourself. Be careful out there, and consider jumping your car with an even more dangerous method instead (but don’t). Video after the break.

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[Leo] Repairs A MIDI Sequencer

We all have that friend who brings us their sad busted electronics. In [Leo’s] case, he had a MIDI sequencer from a musician friend. It had a dead display and the manufacturer advised that a driver IC was probably bad, even sending a replacement surface mount part.

[Leo] wasn’t convinced though. He knew that people were always pushing on the switches that were mounted on the board and he speculated that it might just be a bad solder joint. As you can see in the video below, that didn’t prove out.

The next step was to fire up a hot air gun. Instead of removing the chip, he wanted to reflow the solder anyway. He was a little worried about melting the 7-segment LEDs so he built a little foil shield to protect it. That didn’t get things working, either.

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Cutting Wit And Plastic

If you have ever used a scalpel to cut something tougher than an eraser, you can appreciate a hot knife or better yet, an ultrasonic cutter. Saws work too, but they have their own issues. [This Old Tony] uses a hobby store tool to cut some plastic and wood, then demos a commercial ultrasonic cutter to show how a blade can sail through with less brute force. The previous requires some muscle, finesse, and eventually a splash of Bactine antiseptic. The video can also be seen after the break.

This is more than a tool review, [Tony] takes it apart with a screwdriver and offers his snarky comments. On the plus side is that it cuts polystyrene well where a regular knife won’t do more than scratch or shatter it. Meanwhile in the negative category we don’t hear a definitive price, but they seem to cost half as much as his mini-lathe. If you need an estimated return on investment, consider the price of two-thousand X-acto blades, but you may also wish to factor in the reduced hand calluses. While you are shopping, maybe also think about a set of earplugs; when the video gets to 17:30 he tries to cut a ceramic fitting and manages to make a child-deafening screech instead. We warned you.

This is a fitting follow-up to his unsuccessful attempt to turn an ultrasonic cleaner into an ultrasonic cutter, but we have seen success converting a tooth scaler into a cutter.

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1973: When Calculators Were Built Like Computers

Should you ever pick up [Steve Wozniak]’s autobiography, you will learn that in the early 1970s when his friend [Steve Jobs] was working for Atari, [Woz] was designing calculators for Hewlett Packard. It seems scarcely believable today, but he describes his excitement at the prospects for the calculator business, admitting that he almost missed out on the emerging microcomputer scene that would make him famous. Calculators in the very early 1970s were genuinely exciting, and were expensive and desirable consumer items.

[Amen] has a calculator from that period, a Prinztronic Micro, and he’s subjected it to an interesting teardown. Inside he finds an unusual modular design, with keyboard, processor, and display all having their own PCBs. Construction is typical of the period, with all through hole components, and PCBs that look hand laid rather than made using a CAD package. The chipset is a Toshiba one, with three devices covering logic, display driver and clock.

The Prinztronic is an interesting device in itself, being a rebadged 1972 Sharp model under a house brand name for the British retailer Dixons, and that Toshiba chipset is special because it is the first CMOS design to market. It was one of many very similar basic calculators on the market at the time, but at the equivalent of over 100 dollars in today’s money it would still have been a significant purchase.

Long-tern Hackaday readers will remember we’ve shown you at least one classic calculator rebuild in the past, the venerable 1975 Sinclair!

Old Wattmeter Uses Magnetics To Do the Math

Measuring power transfer through a circuit seems a simple task. Measure the current and voltage, do a little math courtesy of [Joule] and [Ohm], and you’ve got your answer. But what if you want to design an instrument that does the math automatically? And what if you had to do this strictly electromechanically?

That’s the question [Shahriar] tackles in his teardown of an old lab-grade wattmeter. The video is somewhat of a departure for him, honestly; we’re used to seeing instruments come across his bench that would punch a seven-figure hole in one’s wallet if acquired new. These wattmeters are from Weston Instruments and are beautiful examples of sturdy, mid-century industrial design, and seem to have been in service until at least 2013. The heavy bakelite cases and sturdy binding posts for current and voltage inputs make it seem like the meters could laugh off a tumble to the floor.

But as [Shahriar] discovers upon teardown of a sacrificial meter, the electromechanical movement behind the instrument is quite delicate. The wattmeter uses a moving coil meter much like any other panel meter, but replaces the permanent magnet stator with a pair of coils. The voltage binding posts are connected to the fine wire of the moving coil through a series resistance, while the current is passed through the heavier windings of the stator coils. The two magnetic fields act together, multiplying the voltage by the current, and deflect a needle against a spring preload to indicate the power. It’s quite clever, and the inner workings are a joy to behold.

We just love looking inside old electronics, and moving coil meters especially. They’re great gadgets, and fun to repurpose, too.

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1,000 Watt Power Supply Tear Down And Repair

[TheSignalPath] wanted to repair a broken Instek PSW80-40.5 because it has a lot of output for a programmable power supply — 1,080 watts, to be exact. This isn’t a cheap supply — it looks like it costs about $2,200 new. The unit wasn’t working and when he took it apart, he found a nasty surprise. There is a base PCB and three identical power supply modules, and virtually no access without disconnecting the boards. He continued the teardown, and you can see the results in the video below.

Each of the power supply modules are two separate PCBs and the design has to account for the high currents required. The power supply is a switching design with some filtering on the motherboard. One of the boards of the power supply module rectifies the incoming line voltage to a high DC voltage (about 400 volts). The second board then does DC to DC conversion to the desired output.

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Poké Ball Plus Teardown Reveals No Pikachu Inside

The latest entry in the fan favorite franchise Pokémon saw release earlier this month alongside a particularly interesting controller. Known as the Poké Ball Plus, this controller is able to control Pokémon games that are available on completely separate platforms, as well as transfer data between them. It rumbles, It talks, it lights up, it’s wireless, and [Spawn] uploaded a video that reveals what’s really inside.

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