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ArcticMyst Security by Avery

Broken diode or driver?

awlego

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Oct 9, 2009
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I recently purchased a new green module from modwerx and was extremely pleased with it. I tried to put it in a flashlight host with a heat sink after bypassing the switch and soldering it to the switch in the host. It worked great when I tested it just before I made the final mounting. Then I sealed everything up and now it doesn't work...

So I took the module out and and tried again to test if there was some bad connection when I put everything inside, but now my laser won't turn on at all :/

I've tried resoldering everything on the driver. I've resoldered the pins. I put new wires on...

still no laser light. Or regular light for that matter... not even the 808nm, so I doubt that I broke the green part of it.

It never ran for more than a few seconds, and being a >10 mW it wasn't running very powerful. It was already hooked up to everything and ran smoothly so I doubt electrostatic shock killed it. The only thing I can think of is that when I put it in the flashlight the driver board bent a little... I just straightened it. This bending happened maybe 5 or 6 times in the process of trying to fit the module into the custom host.

Any ideas what's up?


Also, while I'm talking about (possible) dying diodes, my PHR that I harvested died soon after hooking it up to my LM317 driver. I harvested it, following Jayrob's very helpful video's, put it in an aixis module, then carefully pressed it in using the back of the aixis module. I then hooked it up to my LM317 driver (which I tested beforehand using a DMM and I know it works) which can vary current from 37mA to 125mA using a large pot. I successfully ran the entire range of current, then realized my diode wasn't flush and so tried to press the diode in further. In doing so I disconnected, then reconnected my driver... without shorting the cap :/ Is the reason this one died because of the surge from the capacitor? I'm using a 16V 470uF electrolytic capacitor. I'm betting this is the case... oh well it's my first harvested diode. Live and learn, no?

By the way, any idea what the specs on the red diode that comes in the PHR sled are? Voltage = 2.5-3 I'm assuming? How much current are these rated for? I'm interested in using it as a test diode for some circuits...

Thanks so much!

Awlego
 





Joined
Aug 15, 2009
Messages
1,443
Points
48
For the green: the driver pcd is directly soldered to the diode's pins. So bending it would pull on those pins and pull the diode away from the crystals. The diode is practicaly against the crystals, any distance between them and the beam of the diode diverges and becomes too low in power density. Possible explanation, possible solution: push back.

the PHR: LM317 drivers are crude, diodes are fragile. Solder everything solid together and they work fine, but when the become disconnected, they charge the caps in a bout 5ms in your case. Then, when the diode connects, the cap discharges at a too high current. an overvoltage protection circuit can prevent this, but simple driver don't have this. It's common on lab drivers, but usually not needed for pointers if everything is fixed....
 

awlego

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Joined
Oct 9, 2009
Messages
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Thanks for the reply. I tried pushing the diode in... it didn't move at all and still doesn't work.

I tested the circuit with my DMM and compared it to a driver a knew was working from another green module. Both worked the same - 1.8 volts at 300mA.

Maybe I blew the IR diode somehow...
 
Joined
Aug 15, 2009
Messages
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Points
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Do you have a power meter? Measuring the output of the diode is one of the few possibilities to test the diode, they emit even a few mW when broken, but nowhere near the hunderds of mW when working.
 




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