Saving $20,000 USD With a Single LED

carrier

[N8Mcnasty] is a HVAC tech who works on some big machines. One of his charges is a Carrier 19EX Chiller, rated at 1350 tons of cooling. 1 ton of cooling = 12,000 BTU. This particular chiller contained an odd LCD screen. It used a fiber optic bundle and a halogen light for backlight illumination. The system worked fine for over a decade. Now though, the halogen bulb has begun melting the glue on the fiber bundle, causing a dim display. The display in question shows some very important operating parameters, such as oil temperature, current draw, and process temperatures. Since they couldn’t easily see the display, the machine’s operators weren’t running the machine, placing stress on the other chillers in the building’s physical plant. [N8Mcnasty] tried repairing the bundle, however the glue kept melting.

A replacement display was no longer available, meaning that the entire chiller control system would have to be upgraded to a newer system. The new control system uses different sensors than the old one. This is where things start getting expensive. Replacing the sensors would also require draining the 15-20 gallons of oil, 4500 lbs of R134a refrigerant, and bringing the whole system down for almost two weeks, a $20,000 job. Rather than go this route, [N8Mcnasty] found an alternative. LED’s have come a long way since 1996, when the chiller was built. He simply replaced the halogen bulb with an LED and appropriate resistor. [N8Mcnasty] was even able to reuse the halogen bulb bracket. A bit of heat shrink tube later, and the fix looks like it was a factory option. He’s documented his fix here on reddit.

Fail of the Week: Baby Monitor Hack Ends in Facepalm

fotw-baby-monitor-repaired-the-hard-way

Editor’s Note: This was the last Fail of the Week tip we had stored up. If you want to see the series continue on a weekly basis we need help finding more documented fails! Please look back through your projects and document the ones that didn’t go quite right. We also encourage you to send in links to other fails you’ve found. Just drop the links in our tips line. Thanks!

Now on with business. This is a baby monitor which [Eric] cleverly repaired, only to realize that he more than likely did it the hard way. The monitor was broken and went unused until his son figured out how to climb out of the crib, so he figured it was time to start monitoring again. Pulling the unit from the brink of the parts bin he set to work repairing the broken power connector.

Further inspection of the power adapter showed that it was spec’d to put out 5V at 1A. This falls in line with USB power, so he clipped the end off of a USB-B cable and used a hunk of proto-board to inject the 5V lines into the device. It was when it came time to reassemble the case that he flipped the board over and discovered an existing USB-B port. He could have just cut a hole in the case to get at the connector and plugged the un-altered cable in directly. Oh well… we’re sure it was fun figuring out his own custom solution!


2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

Repairing Bose Active Noise Cancelling Headphones

QC15 Disassembled

[Mansour] was disappointed to find out that his Bose QC15 headphones had a dead right channel. These headphones have active noise cancelling, which uses a microphone to capture ambient noise and digital signal processing to insert an out of phase signal. Since they’re quite expensive, [Mansour] was determined to resurrect them.

First, he determined that the right speaker had died, so he found a replacement on eBay. These were designed for a different set of headphones, but matched the impedance of the original Bose part. After replacing the driver, it seemed that the repair was a failure. The sound cancelling wasn’t working, and a the playback was high-pitched. As a last attempt, he potted the speaker with glue, to match the original construction. Much to his surprise, this worked.

The problem was that the new driver didn’t have sufficient sound isolation from the microphone, which is meant to pick up passive noise. This feedback likely caused issues with the noise cancelling DSP. A little glue meant a $20 fix for a $400 pair of headphones.

Repairing and Adding Bluetooth Control to an Induction Cooker

When his 6 years old induction cooker recently broke, [Johannes] decided to open it in an attempt to give it another life. Not only did he succeed, but he also added Bluetooth connectivity to the cooker. The repair part was actually pretty straight forward, as in most cases the IGBTs and rectifiers are the first components to break due to stress imposed on them. Following advice from a Swedish forum, [Johannes] just had to measure the resistance of these components to discover that the broken ones were behaving like open circuits.

He then started to reverse engineer the boards present in the cooker, more particularly the link between the ‘keyboards’ and the main microcontroller (an ATMEGA32L) in charge of commanding the power boards. With a Bus Pirate, [Johannes] had a look at the UART protocol that was used but it seems it was a bit too complex. He then opted for an IOIO and a few transistors to emulate key presses, allowing him to use his phone to control the cooker (via USB or BT). While he was at it, he even added a temperature sensor.

Repairing Dead USB Flash Drives

crystal

Over the last few years, [Tobias] has repaired a number of USB Flash drives. This strikes us as a little odd, given small capacity Flash drives are effectively free in the form of conference handouts and swag, but we’re guessing [Tobias] has had a few too many friends lose their thesis to a broken Flash drive.

In all his repairs, [Tobias] found one thing in common The crystal responsible for communicating with the USB controller is always broken. In a way, this makes a lot of sense; everything else on a Flash drive is silicon encased in an epoxy package, where the crystal is a somewhat fragile piece of quartz. Breaking even a small part of this crystal will drastically change the frequency it resonates at making the USB controller throw a fit.

[Tobias]‘ solution for all his Flash drive repairs is to desolder and change out the crystal, bringing the drive back to life. Some of the USB Flash drives even have multiple pads for different crystal packages, making it easy to kludge together a solution should you need to repair a Flash drive five minutes ago.

Simple Dremel TRIAC Hack Repair

Dremel Repair

It’s a wonderful thing to see a clever hack repair instead of disposing of a product. The best repair approach is finding exact replacement components, but sometimes exact components can’t be sourced or cross-referenced. Other times the product isn’t worth the shipping cost for replacement parts or you just don’t have time to wait for parts. That’s when you need to really know how something works electronically so you can source suitable replacement components from your junk bin to complete the repair. This is exactly what [Daniel Jose Viana] did when his 110 volt Dremel tool popped its TRIAC after he plugged it into a 220 volt outlet.

[Daniel] knew how the TRIAC functioned in the circuit and also knew that a standard TRIAC of sufficient specifications could be used as a replacement even if it didn’t have the correct form factor to fit the PCB layout. For [Daniel’s] tool repair he had to think outside the box enough to realize he could use some jumper wires and snuggle a larger TIC206E TRIAC that wasn’t meant for the device but still applicable into the housing where there was enough free space. A little shrink-wrap and all was good again. Sure the fix was simple, but let’s not trivialize the knowledge he needed for this repair.

And if you’re wondering if it worked, he notes that he’s been using this tool for three years since the repair. We thank [Daniel] for sharing this tip and allowing us to add this to our tool belt of Dremel repair tricks.

Hacking a Mac Magsafe Jack into a PC Ultrabook

zenbookAir

Something’s fishy about the above-pictured ultrabook: it’s an Asus Zenbook that [WarriorRocker] hacked to use a MagSafe power connector typically found on Macbooks. Most of us probably consider it standard procedure to poke around inside our desktop’s tower, but it takes some guts to radically alter such a shiny new ultrabook. It seems, however, that the Zenbook’s tiny power plug causes serious frustrations, and [WarriorRocker] was tired of dealing with them.

Using information he found from an article we featured earlier this summer on a MagSafe teardown, [WarriorRocker] hit up the parts drawer for some connectors and got to work. He had to modify the MagSafe’s housing to fit his Zenbook while still holding on to the magnets, but he managed to avoid modifying the ultrabook’s case—the connector is approximately the same size as a USB port. Deciding he could live with just one USB connection, [WarriorRocker] took to the board with a pair of side cutters and neatly carved out space for the MagSafe next to the audio jack. He then soldered it in place and ran wires from the VCC and Ground pins along a the channel where the WiFi antenna is routed, connecting them to the original power jack’s input pins.

[WarriorRocker] regrets that he fell short of his original goal of getting the MagSafe’s protocol working: he instead had to hack on his own adapter. We’re still rather impressed with how well his hack turned out, and it did manage to solve the charging problems. Hit us up in the comments if you can provide some insight into the MagSafe’s otherwise obscure innerworkings.

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