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Weird dot shape

anton

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My lasers been sitting for about a month and the dot was fine before. Now the dots all messed up even when it's focused. Anyone know what this is?
 

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Benm

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That looks really odd... can you see anything wrong with the lens (looking at it when removed from the laser)?
 

WizardG

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That looks like mechanical damage or debris in front of the lens. My first guess would be that your lens has popped out of place in its holder.

P.S. Sorry Anton. Doing three things at once. Post deleted.
 
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anton

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It looks like there's something poking out from the side that shouldn't be. Also I can hear something rattling in there when I shake it.
 

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WizardG

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It looks like there's something poking out from the side that shouldn't be. Also I can hear something rattling in there when I shake it.
In that photo it looks like the lens barrel got screwed down until it ran into the face of the diode. If you can take a photo of the raw output of the diode, without a lens, it might tell us whether you diode is OK. If you have another lens you can try that would be a good way to confirm the issue is the lens.
 

paul1598419

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From what I can see it looks like the diode's window is missing. That is some silicate glass that is in the center of the diode. If something happened to damage that widow, there may be shards of it inside the diode case.
 

anton

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In that photo it looks like the lens barrel got screwed down until it ran into the face of the diode. If you can take a photo of the raw output of the diode, without a lens, it might tell us whether you diode is OK. If you have another lens you can try that would be a good way to confirm the issue is the lens.
My first picture is without a lense
 

anton

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From what I can see it looks like the diode's window is missing. That is some silicate glass that is in the center of the diode. If something happened to damage that widow, there may be shards of it inside the diode case.
I can't tell if the window is missing or not but another thing is when I shake the laser while it's on, the weird patters of the dot change.
 

paul1598419

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I can't tell if the window is missing or not but another thing is when I shake the laser while it's on, the weird patters of the dot change.
If you can't see the window, it's probably not there any longer. If it changes when you shake it, it likely has shards inside the diode case.
 

anton

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If you can't see the window, it's probably not there any longer. If it changes when you shake it, it likely has shards inside the diode case.
Is it possible to replace? I probably I can't do it myself but I guess I could send it to someone and pay them to fix it.
 

paul1598419

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Tilt the diode with respect to your light source. If the window is there, you should be able to see glare coming off of it. The only thing that can be done is to replace the diode. There are members here that could do that for you. The cost will depend on which diode it uses.

If I weren't so busy, I could do it for you. But, I'm behind in several projects as it is.
 
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anton

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Tilt the diode with respect to your light source. If the window is there, you should be able to see glare coming off of it. The only thing that can be done is to replace the diode. There are members here that could do that for you. The cost will depend on which diode it uses.

If I weren't so busy, I could do it for you. But, I'm behind in several projects as it is.
I can see the window now, it looks like there's either a crack or debris on it. Also this diode cannot be bought anymore, DTR had a limited supply of them.
 

paul1598419

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What is it? An NDB7875? They are still available elsewhere. Try member Ricker. There are others too.
 

paul1598419

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You can also try Grix as well as Ricker. He had a sales thread updated recently and I think he has NDB7875s cheap too. If all else fails, try the BST threads. You can go to the bottom of the page on new posts and at the right bottom click on the arrow and look for BST, or buy, sell trade.
 

anton

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You can also try Grix as well as Ricker. He had a sales thread updated recently and I think he has NDB7875s cheap too. If all else fails, try the BST threads. You can go to the bottom of the page on new posts and at the right bottom click on the arrow and look for BST, or buy, sell trade.
Do you know if any of them could put it in a 20mm module and set a driver for it? I don't have any tools and the host I have holds a 20mm module so that the diode could be over-driven.
 




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