Fail of the Week: Projector LED Retrofit

fotw-projector-repair

That’s a deal for a project, how hard could it be to fix it up?

If you’re a real hacker we’d wager you’ve fallen for this type of thought process before. [Luft] bought this used Sharp XR-10X-L projector about a year back and planned to retrofit it with an LED bulb. He gathered all the parts and got to work, successfully testing and installing the modifications. But as luck would have it, the project is stuck in some type of boot loop.

This fail is certainly not for lack of preparation. The first post documenting his adventure shows that the hack has been done before, he acquired the service manual for this particular hardware, and he did his homework when ordering the parts. Success requires circumventing some sensors which ensure the case and internals are in place, and making sure the electronic status of the ballast is reported correctly event though it’s not needed for the LED source. Power-on gets as far as illuminating all the indicator lights in green as it should, but is then followed closely by a reboot sequence.

He tried watching the serial port to see if he can get any status info there but no dice. In keeping with the nature of this column, let’s see if we can provide any constructive troubleshooting advice in the comments.


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.

Hair Thin Wires Save a 3DS from the Landfill

Broken Nintendo 3DS

[Anton] recently acquired a broken Nintendo 3DS. When the power button was pressed, the device would start booting up only to shut back down after flashing a blue light and making a popping sound. It turns out this problem is pretty common with the 3DS.

[Anton] could have tossed this device into the landfill, but where’s the fun in that?  Instead, he cracked the device open like any self-respecting hacker would. It didn’t take him long to discover two broken flex ribbon cables. [Anton] could have then searched for replacement cables, but his inner hacker told him he could repair this himself. He carefully scraped the insulation off of the broken traces and then soldered on some hair thin wires to bridge the gap.

All that was left to do was to glue the wires securely in place and feed them back through the hinges. This project is a great example of how a little determination and know-how can keep a useful device from the landfill. If you attempt this repair yourself, you may find this 3DS teardown to be a helpful reference. What devices have you been able to save from an untimely demise?

3 Cheap Hood/Hatchback/Topper Mods to Save Your Noggin

Gas Lift Fixes by Briansmobile1

This is a mod more than a hack but any time you can alter original equipment to maintain its usability is a win-win scenario for you and the environment. Everyone has or knows somebody that has a vehicle and most vehicles nowadays have some type of hatchback or hood where the support solution is gas filled struts. Inevitably these gas filled struts fail with age and the failure is accelerated in hotter or colder climates. If you ever had to replace these items you know they can cost a minimum of $20 to as much as $60 a piece. Most vehicles require two, four or even eight of these costly little devices.

[Brian] from Briansmobile1 YouTube channel documented three simple and low cost solutions. We all probably know of the vice clamp solution but that is cumbersome and still an expensive solution which is not always very handy or fast. Another solution is to cut a piece of rubber hose in a kind of special way so it is easy to put on and take off the shaft and dangles from a string so it’s always available. The best solution was to use a hitch pin also connected to a string or wire. To make the hitch pin work you have to grind a couple of notches on either side of the lift shaft at just the right spot so the pin can be snapped on and prevent the shaft from retracting at your selected height.

We are sure these solutions will come in handy at some time in most everyone’s driving career. Just after the break we will link to all three of [Brian’s] handy videos on gas strut fix solutions. And if you do your own automotive repair we can definitely recommend [Brian’s] channel of over 600 vehicle repair and maintenance videos which normally come with a dose of philosophy and humor.

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Scooby-Doo Alarm Clock Repair

Scooby-Doo_alarm_clock_repair.Still001

This is more of a hack than a repair which is a good reason for me to feature my Scooby-Doo alarm clock repair. I started out trying to simply fix some broken hardware mounts that hold the display and button mechanism within the alarm clock that looks like the Scooby-Doo Mystery Van. During testing I noticed the display was very dim suggesting an unusual current load or other malfunction, plus the alarm was not functional.

One of the coolest features of the alarm was that it made a car honking noise when the alarm was activated. Unfortunately, it turned out that the chip-onboard which produced the honking sound was shorted internally causing some transistor overheating and the dim display. It was impossible to restore functionality of the custom chip-onboard, but lucky for me the data sheets for the LM8560 clock chip revealed that it could directly output a standard alarm beeping sound to a speaker. This required the PCB and some circuitry be configured differently.

In the end the clock’s current load came down to normal parameters, the display was once again bright and the alarm functioned using the standard beeping alarm sound that comes from the LM8560 clock chip. It is sad that the coolness factor of the alarm clock cannot be restored with the honking car sound alarm but my son is quite happy to have his favorite Scooby-Doo alarm clock functioning once again.

The circuit modifications may not have been the cleverest or the best solution, so if you have other suggestions please leave them in the comments below. You can watch the video of the circuit evaluation and repair modifications after the break.

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Current Limiting Diode Use and Tutorial

Current limiting diode 1

Not that this happens often, but what do you do when faced with a repair where you don’t know the power source but you do know you have to drive LED backlighting? When faced with this dilemma [Eric Wasatonic’s] solution was to design for ambiguity. In this interesting hack repair [Eric] needed to restore backlighting for an old car stereo LCD display. First he guaranteed he was working with a DC power source by inserting a small full-wave bridge rectifier. Then knowing he needed 4 mA to power each LED for backlighting he used some 1978 vintage current limiting diodes designed to pass 2mA each regardless of voltage source, within limits of course.

Sure this is a simple hack repair but worthy of being included in anyone’s bag of tricks. Like most hacks there is always knowledge to be gained. [Eric] shares a second video where he uses a curve tracer and some datasheets to understand how these old parts actually tick. These old 1N5305 current limiting diode regulators are simply constructed from a JFET with an internal feedback resistor to its gate which maintains a fixed current output. To demonstrate the simplicity of such a component, [Eric] constructs a current limiting circuit using a JFET and feedback potentiometer then confirms the functionality on a curve tracer. His fabricated simulation circuit worked perfectly.

There was a little money to be made with this repair which is always an added bonus, and the recipient never reported back with any problems so the fix is assumed successful. You can watch the two videos linked after the break, plus it would be interesting to hear your thoughts on what could have been done differently given the same circumstances.

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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 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.