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MERC

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Just finished building a nubm44 build and while swapping a g2 for a 3 element once! something must have gotten on the window and burned now there is a large distortion when unfocused and I am probably losing a lot of power. Will this damage the diode further over time?
 

Alaskan

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Happened to me too, I de-canned it and so far, no loss of power over time, I'm not sure if the loss will get worse, but if too much reflected power from it, your diode may suffer and or fail.
 

paul1598419

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You have to be extra careful when working with this diode. Especially when over driven to 7 watts. Fortunately, they aren't an expensive diode. You can decan it like Alaskan did, or just change it out.
 

Bacon

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I'm curious; what does it look like, and long did it go before you noticed it was too late?

I try to keep a can of air around when removing lenses because this scares me.
 

astralist

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I always suspected that the concave lens in the 3EL reflecting and focusing enough power to melt the LD's window.
Because it also happened to me :(

If there are some debris at the beginning, it should have melted since the beginning of turning on laser.
BUT, it happened only when i try to turn/adjusting focus of the 3EL.

I need ppl to reproduce this scenario to prove it :(
since it's rare to see ppl here using 3EL for NUBM44, they never experienced this problem (?)
 

RedCowboy

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Happened to me, it's why I 1st joined here, I was running a 3 element on a NUBM44 @ 5 amps and it was a strong diode, a freak maybe, here's what it looked like....granted I think trash got on the window because I have many NUBM44's right now that work fine and have been working for many many hours, I do now run @ 4.5 amps and I use G7 lenses with 3X beam expanders so the G7 never gets touched, I focus with the beam expander, or when I use a G2 with cylindrical pairs I also never touch the primary ( G2 )

Too be fair I have also done this to a M-140, but out of well over a dozen NUBM44's only this 1 did I crack the window.

 

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Bacon

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Hummm. I have an old m140 thats about 1.6w and has always used a 3E, and still going.
Ive used it outdoors many times, and its taken some beatings. :evil: but not even close to a NUBM44 :undecided:
 
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MERC

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Yup it looks almost identical to the picture you posted RedCowboy. I don't think the g2 lens is very good for focusing it anymore its about 2'' at 10' I didn't get to use it much at all before hand so idk if that's normal. I don't have the tools to de-can so I'm just going to run it as is and if it dies lesson learned.
 

Alaskan

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I’ve seen one method of de-cannng using pliers and a small vice, it’s easy without needing to buy one of those expensive Thorlabs tools. I’m using my iphone and web seaching right now is a chore (tried) to find a link to some photo’s showing how easy it is, anyone?
 
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Richie89

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im so affriad im gonna get dust particles on my diode window that i change my lens in my car now, it sounds crazy but their is much less dust in your car, I ran a small experiment by using my Thrunite TN40 at night in my car to see how much dust was floating around in there and their was almost no visible dust in my car in the beam of my high intensity flashlight whereas my house seemed to have it floating everywhere.
 




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