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First build, assembled, not turning on

Android

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Hey there LPF!

I recently purchased a kit from survival laser (I can't link but it was a "Bargain No Diode Host Bundle) and got to assembling it today. My diode of choice was a Mitsubishi 500mW 638nm Diode, with the included 1.0A driver in the kit. After pressing the diode, I soldered the diode to the to the driver leads (with the case pin facing down, my negative was on the left, positive on the right) and screwed it all together. Popped in an 18650 and clicked the button. Nothing. Anyone know what I did wrong? Definitely a newbie type question so forgive me for that.

Cheers.
 



Android

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I essentially followed this whilst building.

https://laserpointerforums(dot)com/threads/survival-laser-diy-host-assembly-photo-tutorial-picture-heavy.58889/
 

Hephaestus

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You may have soldered to the wrong diode pin. It looks like the right pin is positive, the middle negative and the left is the case pin.casepin.PNG

Edit: My next guess is you may have mixed up the polarity somewhere along the way. Do you have a multimeter? This will help troubleshoot polarity problems. Which way did you put in the batteries and did you use an anodized heatsink or a bare aluminum one?
 
Last edited:

Android

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You may have soldered to the wrong diode pin. It looks like the right pin is positive, the middle negative and the left is the case pin.View attachment 73135

Edit: My next guess is you may have mixed up the polarity somewhere along the way. Do you have a multimeter? This will help troubleshoot polarity problems. Which way did you put in the batteries and did you use an anodized heatsink or a bare aluminum one?

You may have soldered to the wrong diode pin. It looks like the right pin is positive, the middle negative and the left is the case pin.View attachment 73135

Edit: My next guess is you may have mixed up the polarity somewhere along the way. Do you have a multimeter? This will help troubleshoot polarity problems. Which way did you put in the batteries and did you use an anodized heatsink or a bare aluminum one?
Well, I've gotten it to work! The issue was that I had completely forgotten to solder the brass ring so one end of the battery wasn't connected to the driver. Silly mistake! A new problem has arose though: the power of the laser is incredibly low, with no visible beam in the dark. Same problem with a G2 and G7 lens. In addition to this, the beam is very very bad. It looks incredibly wide and when I do get it focused it still is wide. I have a feeling the power loss might be from me using a 18650 instead of rcr123a's? Thanks for your help man :)
 

Hephaestus

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If you can see light but it's way too dim, then I can think of two possibilities:
1) you already killed the diode
2) you're running the diode just below the threshold current (the diode can't draw enough current to properly lase)
 

Android

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If you can see light but it's way too dim, then I can think of two possibilities:
1) you already killed the diode
2) you're running the diode just below the threshold current (the diode can't draw enough current to properly lase)
ah, not like that, I'll send a picture. I'm running 100ma above recommended at 1A too.
 

Hephaestus

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that looks plenty bright to me! This is a multimode diode so the beam profile will be ugly to say the least... You can play around with the focus but the the beam will always be rectangular like that

Edit: It's a bit hard to tell on the brightness on a second glance. Do you have a LPM? Or something to burn to test it's power?
 

Android

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that looks plenty bright to me! This is a multimode diode so the beam profile will be ugly to say the least... You can play around with the focus but the the beam will always be rectangular like that
Oh, that's great to hear! I was worried because I saw beamshots of some super bright beams but my build can't produce a beam at all.
 

Hephaestus

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Oh, that's great to hear! I was worried because I saw beamshots of some super bright beams but my build can't produce a beam at all.
One should be able to see a beam at 500mW+ of 638nm no problem. Sounds like there's still an issue.
 

Android

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One should be able to see a beam at 500mW+ of 638nm no problem. Sounds like there's still an issue.
Yeah, do you think it could be the battery used? tried 2 different 18650s, same thing, but survival laser recommends 2 rcr123a's or 1 18650 for "some diodes"
 

Hephaestus

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Well you can try 2 rcr123a (16340) batteries and see what happens. These diodes are pretty tough
 

Android

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Well you can try 2 rcr123a (16340) batteries and see what happens. These diodes are pretty tough
I'm going to pick some up on Amazon and report back :)

Thanks for the help thus far, I don't think the diode would be damaged because the driver never even got a negative of the battery so it should be fine (hopefully?!)
 

Unown (WILD)

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One battery is enough as the voltage requirements are lower than 3.7v. Adding more voltage won't do anything. Personally for me a beam of 500mw of 638 is very hard to see. You might just be one of those people that see violet better than red.
 

Android

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One battery is enough as the voltage requirements are lower than 3.7v. Adding more voltage won't do anything. Personally for me a beam of 500mw of 638 is very hard to see. You might just be one of those people that see violet better than red.
Hey there, thanks for chiming in! Yep, tried with 2 123s I had laying around, no dice. Yeah, it could just be working fine, but it does seem a bit faint. Is there any way else I could test it besides visibility? It can't burn anything whereas with my ebay greenie I can burn dark things.

Thanks!
 




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