COB LED Teardown

[Big Clive] picked up some chip-on-board (COB) LEDs meant for hydroponics that were very unusual and set out to examine them on video. Despite damaging the board almost right away, he managed to do some testing on these arrays and you can see the results in the video below. He also compares it to older LED modules.

The 144 LEDs produce a lot of light. In addition to powering the device up, he also looks at the construction of the LEDs under a magnification, comparing the older style that used tiny bond wires to make connections versus the new version soldered on the board directly.

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The Vedolyzer Was High Tech Repair Gear For 1939

There’s an old joke that all you need to fix TVs is a cheater, a heater, and a meter. If you don’t remember, a cheater was a cord to override the interlock on TVs so you could turn them on with the back removed. Of course, in real life, pro repair techs always had better equipment. In 1939 that might have meant the Supreme Vedolyzer which combined a meter, a ‘scope, and a wavemeter all in one device. [Mr Carlson] acquired one that was in fair shape and made a few videos (see below) of the teardown and restoration.

[Mr Carlson] wasn’t restoring this as an art project, by the way. He plans on using it, so he was less concerned with authenticity and more worried about usability. That led him to do things like remove the input jacks and replace them with BNCs. The video series is a bit of a time investment. Part one is about 82 minutes long! But if you are interested in old gear, this is a chance to peer inside an unusual specimen.

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There Are 200 Electronic Kits In That Box

If you grew up in the latter part of the 20th century, you didn’t have the Internet we have today — or maybe not at all. What you did have, though, was Radio Shack within an hour’s drive. They sold consumer electronics, of course, but they also sold parts and kits. In addition to specific kits, they always had some versions of a universal kit where lots of components were mounted on a board and you could easily connect and disconnect them to build different things. [RetoSpector78] found a 200-in-1 kit at a thrift store that was exactly like the one he had as a kid and he shares it with us in the video below.

This was a particularly fancy model since it has a nice looking front panel with a few knobs and displays. The book shows you how to make the 200 different projects ranging from metronomes to rain detectors. The projects really fell into several categories. There were practical circuits like radio receivers, test equipment, and transmitters. Then there were games or circuits even the manual called “silly.” In addition, there were circuits to build simply to understand how they work, like flip flops or counters.

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Piezoelectric Gyro Shows How They Rolled Back in the Day

There’s no doubting the wonders that micro-electromechanical systems (MEMS) technology have brought to the world. With MEMS chips, your phone can detect the slightest movement, turning it into a sensitive sensor platform that can almost anticipate what you’re going to do next. Actually, it’s kind of creepy when you think about it.

But before nano-scale MEMS inertial sensing came along, lots of products needed to know their ups from their downs, and many turned to products such as this vibrating piezoelectric gyroscope that [Kerry Wong] found in an old camcorder. The video below shows a teardown of the sensor, huge by MEMS standards but still a marvel of micro-engineering. The device is classified as a Coriolis vibratory gyroscope (CVG) which, as the name implies, uses the Coriolis effect to sense rotation. In this device, [Kerry] found that a long, narrow piezoelectric element spans the long axis of the sensor, suspended from what appears to be four flexible arms. [Kerry] probed the innards of the sensor while powered up and discovered a 22 kHz signal on the piezo element; this vibrates the bar in one plane so that when it rotates, it exerts a force on the support arms that can be detected. Indeed, [Kerry] hooked the output of the sensor to a wonderfully old-school VOM whose needle wiggled with the slightest movement of the sensor.

Sadly, MEMS made this kind of sensor obsolete, but we appreciate the look under the hood. And really, MEMS chips are using the same principle to detect motion, just on a much smaller scale. Want the MEMS basics? [Al] has you covered.

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What Happened to the 100,000-Hour LED Bulbs?

Early adopters of LED lighting will remember 50,000 hour or even 100,000 hour lifetime ratings printed on the box. But during a recent trip to the hardware store the longest advertised lifetime I found was 25,000 hours. Others claimed only 7,500 or 15,000 hours. And yes, these are brand-name bulbs from Cree and GE.

So, what happened to those 100,000 hour residential LED bulbs? Were the initial estimates just over-optimistic? Was it all marketing hype? Or, did we not know enough about LED aging to predict the true useful life of a bulb?

I put these questions to the test. Join me after the break for some background on the light bulb cartel from the days of incandescent bulbs (not a joke, a cartel controlled the life of your bulbs), and for the destruction of some modern LED bulbs to see why the lifetimes are clocking in a lot lower than the original wave of LED replacements.

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Recover Data From Damaged Chips

Not every computer is a performance gaming rig. Some of us need cheap laptops and tablets for simple Internet browsing or word processing, and we don’t need to shell out thousands of dollars just for that. With a cheaper price tag comes cheaper hardware, though, such as the eMMC standard which allows flash memory to be used in a more cost-advantageous way than SSDs. For a look at some the finer points of eMMC chips, we’ll turn to [Jason]’s latest project.

[Jason] had a few damaged eMMC storage chips and wanted to try to repair them. The most common failure mode for his chips is “cratering” which is a type of damage to the solder that holds them to their PCBs. With so many pins in such a small area, and with small pins themselves, often traditional soldering methods won’t work. The method that [Jason] found which works the best is using 0.15 mm thick glass strips to aid in the reflow process and get the solder to stick back to the chip again.

Doing work like this can get frustrating due to the small sizes involved and the amount of heat needed to get the solder to behave properly. For example, upgrading the memory chip in an iPhone took an expert solderer numerous tries with practice hardware to finally get enough courage to attempt this soldering on his own phone. With enough practice, the right tools, and a steady hand, though, these types of projects are definitely within reach.

[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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