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Thread: Beam/dot issues on my red

  1. #11
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    Weird. The red shape in the bottom pic is 90 deg out from the red shape in the red shape in the top of the thread. I wouldn't have expected that.

  2. #12
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    well ive been playing roiund with it, so that might have something to do with it.

    ok took the dichro out and used a red and green laser, its not the dichro.

    used a green pointer and put it straight throught the galvo mirrors and its comes out a funny shape.

    so what can i do about this???
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  3. #13
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    Is there power to the galvos?

  4. #14
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    Quote Originally Posted by andy_con View Post
    ok looks like its not a red problem
    Process of elimination...

    With everything in place, drop a good FS mirror in the path of the red laser at 45 degrees (being very careful of back reflections into the diode) to steer the beam out of the front of the projector and see if it's nice and round. If it's ok, then move down the line and bypass any steering mirrors & check again. If that's ok, try bypassing the mixing optic then if that's ok it must be the scanners (that would be unusual)
    Got any pics showing the current layout of the inside of the projector?
    What are you using to mix the beams - dichro or PBS? and where did it come from?

    Edit: Looks like if it only happens with the scanners powered and any laser directly pointed onto them, then maybe you have a ground loop issue causing a slight hum.
    Last edited by p1t8ull; 07-10-2007 at 14:47.
    A little bit werrrr, a little bit weyyyyyy, a little bit arrrrgggghhh

  5. #15
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    Oh yea, did you check to make sure that the red laser is hitting the scanner mirrors in the middle and not getting chopped off on the edges? I think I have seen some ulgy patterns on my lasers if they weren't aligned properly with both scanner mirrors.

  6. #16
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    The first picture shows echoes. Look for two surfaces repeatedly reflecting to each other. If your galvo mirrors are polished both sides but coated on one side, check that you're not shining on the uncoated side.

  7. #17
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    Quote Originally Posted by Dr Laser View Post
    Is there power to the galvos?
    yes theres power to them

    Process of elimination...

    With everything in place, drop a good FS mirror in the path of the red laser at 45 degrees (being very careful of back reflections into the diode) to steer the beam out of the front of the projector and see if it's nice and round. If it's ok, then move down the line and bypass any steering mirrors & check again. If that's ok, try bypassing the mixing optic then if that's ok it must be the scanners (that would be unusual)
    Got any pics showing the current layout of the inside of the projector?
    What are you using to mix the beams - dichro or PBS? and where did it come from?

    Edit: Looks like if it only happens with the scanners powered and any laser directly pointed onto them, then maybe you have a ground loop issue causing a slight hum.
    i have done some elimination.

    im pretty sure ots not the red lasers, as when the green goes through the galvo mirrors it becomes 2 - 3 times bigger.

    i used a green laser pinter and put that throught the galvo mirrors and it came out a funny shape. so its gota be the galvo mirrors.

    Oh yea, did you check to make sure that the red laser is hitting the scanner mirrors in the middle and not getting chopped off on the edges? I think I have seen some ulgy patterns on my lasers if they weren't aligned properly with both scanner mirrors.
    there is like half a mill not hitting the mirror top and bottom. but the green hits fine.

    The first picture shows echoes. Look for two surfaces repeatedly reflecting to each other. If your galvo mirrors are polished both sides but coated on one side, check that you're not shining on the uncoated side.
    will check tonight.

    heres a linkt to my site with lots of pics of my scanner

    http://www.laser-man.co.uk/2006/inde...id=45&Itemid=6
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  8. #18
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  9. #19
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    [quote=andy_con;25711]yes theres power to them

    Turn galvos off but leave the laser on and see whats gonna happen.

  10. #20
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    bit hard.

    i just took the galvos out and cleaned the mirrors and put my green pointer through them and they seem fine??

    i cant work out the problem
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