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Laser drastically reducing power immediately

hwang21

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I would start saving up for a new laser if I were you, but I still have never heard of someone killing their laser due to mode shifting via temperature changes :thinking:
 

MacDaddy

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Just thought I'd add this: the beam which is usually like a mm is now about 6mm wide........ more than double my WL Arctic's beam in 445nm
 

BShanahan14rulz

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Anything rattling in the head? My first thought was with everyone else: bring it up to a normal temperature and let the laser's temp stabilize. Kind of like how if you bring a screwdriver or hammer inside, the handle gets to a nice temp quickly, while the metal stays cold.
Then, give that a shot with a fresh battery and see if it still mode-hops.

My second thought was the batteries. Less likely because it suddenly decided to dislike your batteries? But, there are many batteries that have the correct voltage when metered on a voltmeter, but just can't put out the amps. Usually, they are china brands, and some china brands are so bad that they are simply trash cells that were picked out of a pile and wrapped up in a pretty wrapper.

My third thought is that a lens has been knocked free from it's "mount." In compact units, the mount usually consists of whatever metal is closest, plus a dab of epoxy. Rattling noise in the head would verify this. the lenses are tiny, and the one that would get knocked loose would probably be about the mass of half of an airsoft pellet, so imagine the feeling and plastic-y sound of half an airsoft pellet in there.

Can you get pics of the now larger dot, and possibly a pic of the dot after shining through a lens to give us a better idea of how much larger your dot is, and to verify for sure whether it is mode hopping?
 

KRNAZNBOY

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Maybe you should see if you can send the laser to a member, who can effectively diagnose the problem.

:beer:
 

MacDaddy

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Anything rattling in the head? My first thought was with everyone else: bring it up to a normal temperature and let the laser's temp stabilize. Kind of like how if you bring a screwdriver or hammer inside, the handle gets to a nice temp quickly, while the metal stays cold.
Then, give that a shot with a fresh battery and see if it still mode-hops.

My second thought was the batteries. Less likely because it suddenly decided to dislike your batteries? But, there are many batteries that have the correct voltage when metered on a voltmeter, but just can't put out the amps. Usually, they are china brands, and some china brands are so bad that they are simply trash cells that were picked out of a pile and wrapped up in a pretty wrapper.

My third thought is that a lens has been knocked free from it's "mount." In compact units, the mount usually consists of whatever metal is closest, plus a dab of epoxy. Rattling noise in the head would verify this. the lenses are tiny, and the one that would get knocked loose would probably be about the mass of half of an airsoft pellet, so imagine the feeling and plastic-y sound of half an airsoft pellet in there.

Can you get pics of the now larger dot, and possibly a pic of the dot after shining through a lens to give us a better idea of how much larger your dot is, and to verify for sure whether it is mode hopping?



So, yeah, I love you sir. Tiny little rattling noise. What you said makes perfect sense. I will try and get pics up by tomorrow. But I think that's what happened.
 

hwang21

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That doesn't really explain the mode hopping though... but do post pics, that will help
 

aryntha

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What kind of laser is it? I thought a laser I had was dying and it -was- actually a loose optic. One of the slotted metal rings had worked its way loose, and when held a certain way, the lens was at a slant, causing the beam to widen.

I wonder if the 'time based' dimming after a few seconds could be reflectivity back into the optics causing some change in lasing... I've seen that happen - I forget exactly what I did but shining one laser into another would "shut one off". I'm just remembering this vaguely so it could have had a photodiode in there, too.

In addition to pics I'd like to see a video of it going on, though I know that's more difficult to get posted.
 

MacDaddy

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So the Bluetooth on my laptop was acting up so I had to get it fixed, but here are the pictures of the beam and dot. The beam is basically invisible so I had to get my buddy to blow smoke into the beam to show you guys how it looks. and the dot shot is from about twenty feet away from the surface where I took the pic. The dot is over an inch.
 

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The Lightning Stalker

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It looks like either the expanding lens or the collimator has come loose. If you can open it up, grab it with
some tweezers and glue it back in place with some epoxy being very careful not to get any on the central
portion of the lens. Super glues are absolutely the wrong thing to use and will ruin the optics. That should
get it going but it will never be the same. You could also send it to one of us if you don't feel comfortable
doing the repair yourself.
 

BShanahan14rulz

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Was that output with the rattling lens not attached, or did you put that piece back on the laser before showing that output on the wall?

If that output was without the loose piece, then the blob's movement is caused by the crystal set itself and cannot be easily fixed, but if it is with the lens in place, it may still just be that lens moving around and having the laser shining through it at all sorts of odd angles.

Consider for a moment this image:
http://laserpointerforums.com/attachments/f45/36385-new-diode-green-laser-module-green-laser-pointer-dpss-diagrams.jpg

The part labeled "Collimating Lens" is the part that I think is rattling in your build. This may be because it is completely loose from the brass threaded ring that it is mounted to (bad), or just the brass threads having been cut with very low tolerances (less bad; I have a green module that produces this rattling noise, but it is just the brass nut not threading snuggly in the barrel's threads).

The part labeled "Expanding Lens" is shown mounted in a mounting block and epoxied to the barrel. Usually, this is a plastic lens that is just glued in with some glue, and can pretty easily become dislodged. You should be able to see this lens inside of your laser after removing the front piece that has the outer, collimating lens.

However, with that part removed, you should end up with a highly divergent, circular blob, not the crazy looking splotchy design you show in your video.

This would mean that the problem lies somewhere between the laser diode and the expanding lens. It could be that the expanding lens is melting. It could be that the crystal set has fractured. These things I cannot say for sure. Electrically, though, it would seem that your laser is functioning properly. It is just what happens after the laser diode spits out its photons that is where things are going wrong.

Let's see if more folks may have experienced this specific issue :beer:
 

The Lightning Stalker

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Is that is a 2-piece focusable design? I've never seen one like that before. That is pretty interesting, but
honestly it's probably time for a new laser. Unless the back half is a standard 12mm module, there is no
drop-in replacement.
 




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