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Diode not working when inside heatsink

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sometoymachine

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Hi everyone. I feel like Im making an obvious mistake somewhere but its been over a month since I've worked on this build because of the delay on shipment of my 32600 batteries.

I am using Jayrobs 2D Mag heatsink inside my host with an LM317 DDL and a red diode. I tested the load and all is well. I even connected the diode to the + and -. The laser works fine with the aixiz housing hanging out of the flashlight but when i turn it off and push the housing into the heatsink, its like its grounding out or something as soon as it touches it.

Also, I have connected the + to the positive pin of the diode and the - to the case negative.

Any ideas? Im lost.
 





chipdouglas

chipdouglas

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pix will help. or a quickie youtube... but questions first

it works when it is out side of the flash light, but not when you put it in? when you pull it back out does it work right away, or do you have to do minor adjustments?

do you have it connected correctly to the power switch of the host? that is probably the culprit? it could be connected wrong or a faulty clicky switch. use your continuity tester to check the switch.

michael.
 
Kookapeli

Kookapeli

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You need to Isolate the heatsink from the host, I used a bit of PTFE tape or plumbers tape to stop the heatsink from touching the host as the Red diodes are case negative/positive cant remember which so it needs to be isolated
 
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sometoymachine

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I just rode away from my house so I don't hve immediate access to it or to take pictures.

I also pulled the heatsink out of the light and when the housing is just in the heatsink, away from the host, the same happens. So do I need to insulate between the housing and the heatsink, or between the heatsink and the host?
 
Kookapeli

Kookapeli

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isolate the heatsink from the host, the module still needs to dissapate heat into the heatsink :)
 
Kookapeli

Kookapeli

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Ha ha, no probs, it's mid evening here so that's why I'm on the ball ;)
 
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sometoymachine

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Hmm. Ok. That didn't work. Still the same issue. It must have to do with the lm317 being posted into the bottom of the heatsink. The only way it works is for the housing not to touch the heatsink. But that defeats the purpose of the heatsink?

I'm running out of ideas. What about the other pin of the diode? Or is there a way to ground it properly so it doesn't shut off?
 
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sometoymachine

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Well wonderful. Another died fried. I only have one left now. This project has cost me 4 diodes already. I'm so pissed.
 
Kookapeli

Kookapeli

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Did you build the driver yourself ??? If so make sure that no wires are touching the host or heatsink, when you put it together it could be shorting somewhere but when you take it out, it has no where to short too, mabe ???
 
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anselm

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Remember the back of the lm317 connects to it's output(positive)!
So if that touches the heatsink->case of diode->negative, obvious short there.
 
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