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DDL driver kills 635nm diodes?

H

hydrogenman15

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A while back I bought a few 7mW 635nm diodes on ebay. The first one I made had a faulty driver (negative was going into the LM317). It turned on and and functioned just fine. Later on, I realized that I had soldered the driver wrong and I made a new driver. Tested it on a dummy load. Everything checked out and the driver was delivering exactly the right amount of current (38mA's). I made sure to short out the cap and everything before soldering it to the diode and turned it on... Nothing, no light, no flash and no current. So i hooked it up to the faulty driver and nothing. I checked everything on the driver over and over then tried a new driver on a new diode... The same thing happened.

I really have absolutely no idea whatsoever and to what killed them and I'm wondering if anybody has had the same thing happen.:can:
Here are the diodes I was using

**EDIT** What a strange coincidence... This is post 635...http://cgi.ebay.com/3-pcs-635nm-red...in_0?hash=item1c0b9e0982&_trksid=p3286.c0.m14

--Hydro15
 
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If the first driver worked, why do you think it was faulty?

Your link is to a DiY tutorial, no mention of 635nm diodes.
 
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dr-ebert said:
If the first driver worked, why do you think it was faulty?

Your link is to a DiY tutorial, no mention of 635nm diodes.
Click to expand...

:wtf: I think I might had copied that earlier and somehow it got pasted when I posted this.

Anyways... The first driver was not even regulating current cause the negative was going into the LM317 and it won't work properly if the positive isn't going through it. The faulty driver was pretty much just a 100ohm pot and a capacitor.

--Hydro15
 
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There is nothing inherantly wrong with the LM317 circuit that would cause it to kill any LD, if it is set up correctly. It is much more likely you damaged it removing it from one driver (did you short the cap before removing it?) or attaching it to the new one.

Regards rog8811
 
rog8811 said:
There is nothing inherently wrong with the LM317 circuit that would cause it to kill any LD, if it is set up correctly. It is much more likely you damaged it removing it from one driver (did you short the cap before removing it?) or attaching it to the new one.

Regards rog8811
Click to expand...

I definitely shorted the cap (the entire time I was soldering it) and grounded myself as well. I tried many different drivers on many different diodes and none of the emitted any light at all. I built all the drivers using the exact components in the exact configuration as the original DDL circuit diagram. The only thing I could think of was that maybe the cap was not quite big enough to handle the possible burst it took when it first started up. I also tried the driver on a phr red and a ps3 red and both worked just fine.

--Hydro15
 
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Very strange indeed. I have had really good luck with the DDL driver in the higher output LD's. The only time I have killed diodes connected to the DDL were with intermittent connections on the diode or doing what most do with an over-current situation. Hope you find the solution.
 
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