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Thread: Gavlo sabotage

  1. #1
    Join Date
    Dec 2009
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    MI, flint, farmington hills
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    569

    Default Gavlo sabotage

    So I was living with some people who back in they day sat there and watched me tune my galvos for about 5 straight hours.
    I moved out but left stuff behind.
    And i got my scanners out to see and noticed the glue lines weren't where they should have been.
    They turned them all different ways.
    They now produce an image that looks like crap.
    The one guide i do have is to not start from zero.
    But it looks like im going to need to start with all the pots at zero.
    there are scanpros 20s.
    any thing at all is helpfull.
    i know the whole 3 legged stool reference but i think mine is now missing legs.

  2. #2
    Join Date
    Feb 2010
    Location
    Melbourne, Australia
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    Default

    Here's an idea, though folks like Buffo would certainly know more on this than I...

    Before powering up, it should be possible to turn the gain right down on your drivers. Then power up the drivers with the DAC signal wires connected to the drivers, ensure you have no movement and instability when no signal is applied from the DAC (no show is playing etc). Then apply a small signal you have prepared e.g. a small circle centered in the projection area. The intent here is so you can get stability in a basic and uncomplicated image first by adjusting the HF and LF damping (as you should assume these are adjusted out of their correct settings). You might need to turn up the gain slowly from the lowest setting to see anything. At the first sign of instability, back off on the gain and try to tweak the LF and/or HF damping to get a stable small circle.

    Provided your gain is still low, you can probably move on to the ILDA 12K test pattern to see how out your LF or HF damping is. Key thing is to initially try to get the circle in the pattern to a stable circular shape. If you can do this then you should be well on the road to increasing the gain progressively following Buffo's scanner tuning guide (tweaking the LF and HF damping as you go).

    Do your adjustments gently and slowly. If you don't see any difference, either your gain's too low or your not in range for the LF or HF damping to have effect (though this doesn't mean the LF or HF setting won't have a big effect once they come into range).

  3. #3
    Join Date
    Dec 2009
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    MI, flint, farmington hills
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    Default

    okay so i got them back in somewhat tune.
    Every thing looks good now but the lasermedia test patter has the retrace ovals on the diagonals.
    No matter how i try between the 2 gavlos i cant get them to over lap.
    I add gain to the one and take a little away from the other. to bring them to speed.
    Maybe i have the gain and LF way to high?
    I kept going on the square test pattern till when i added more gain nothing would happen i then dialed it back a few turns then added lf and a little hf to correct.

    Any time i get them near all the other stuff like the square get out of shape.
    the ilda pattern looks good to but the center circle looks kinda like the upside down cancer ribbon.
    so they are working but it took me a good 3hrs to get them even to this point.

  4. #4
    Join Date
    Feb 2010
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    Melbourne, Australia
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    Default

    The key thing is the circle inside the square on the ILDA pattern.

    Two things to check, scan angle and scan rate. If you can't get a perfect circle, these might be too high. Try slowing the scan rate while the pattern is showing, does the circle grow and become more geometric?

  5. #5
    Join Date
    Aug 2009
    Location
    Churchill(hour S from Houston)
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    Default

    the SPCL--needs to hear about this.
    the Society for Prevention to Cruelity to Lasers... did they really think you would not know what they did?
    what A-holes! Reminds me of other stories I have heard of laser haters doing things like this--sad. I had a tiny 2mW hene tube and mirrors get smashed at a new years party, ... it was part of a swell full control spiro rig a good friend made for me. Some find humor is sick shit like that.

    Hope you can get them tuned again.

    len

  6. #6
    Join Date
    Jan 2006
    Location
    Charleston, SC
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    2,147,489,242

    Smile

    So long as you (or someone else) has only been adjusting the high frequency damping, low frequency damping, and servo gain pots on the amps, you can always get them back in tune.

    However, it sounds like you are experiencing other issues. If someone has adjusted the position offset, or linearity, or one of the other pots that are pre-set from the factory, then I'm afraid you may be stuck. I don't have any instructions on how to get those adjustments back where they should be.

    First: make sure you aren't scanning too wide. Start at around 3 to 4 degrees. This is very small! The image should only be about 70 cm tall at a distance of 10 meters. (Or roughly 24 inches high at a distance of 30 feet)

    Second: try to adjust the ilda test pattern so the center circle actually looks like a circle and is just touching the sides of the square. Make sure there is no overshoot or undershoot on the corners of the square either.

    Finally: check the lasermedia test pattern. If you still have "ovals" on the diagonal re-trace lines, you can try to play around with the tuning a bit to get them closer (hint: high-frequency damping will have a large effect here), but if your choice is between a lousy looking circle or some line separation on the retrace lines, you will be better off with some separation on the retrace lines. You want that circle perfect though.

    If you can't get a circle no matter what you try, then dial all three controls (HF damping, LF damping, and Servo Gain) down to zero and start from scratch. If that still doesn't work, then it's likely that someone adjusted one of the other pots by accident. And in that case, I don't know what to tell you.

    Adam

  7. #7
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    Dec 2009
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    Default

    Okay thanks guys for the help after over 10 hours of working at them adjusting every pot ive gotten them back to a somewhat good fashion.
    Im using my cmedia V1 sound card its the square one not the L shaped one. (got a new audiolase plus sound card off the BST section coming)
    LFI player Set at a bit above 12k.
    http://www.lasershowparts.com/files/.../SCANPRO20.pdf
    luckily my amps only have 4 pots the last being position scale.
    All have been adjusted. i still get retrace on the laser media but i do not care at this point.
    Now please forgive my current setup.
    yes that is a plastic cutting board that my 445nm is on but below that there is a 1/2in thick aluminum plate.
    The galvos and amps are mounted to.
    So here is a quick video of what 10 hours of work get you with scanners.

    http://s755.photobucket.com/albums/x...0903132952.mp4

    yes that is me in the video.
    Also waiting for the email from dr.Lava for ild SOS. paid for it a day or 2 ago and still no contact...
    I cant even DL the software yet for ILD SOS, is there a link or does he have to send you everything?

  8. #8
    Join Date
    Feb 2010
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    Default

    That image looks fine to me. Good job!

  9. #9
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    Dec 2009
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    MI, flint, farmington hills
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    Default

    PS thats a video

    is that a good scan angle for 20k? its hard to tell
    i want to be able to write my name but dr lava has yet to send me any information about my order for ild sos. i paid and got nothin.
    i just want to see kiyoukan displayed by my scanners i got the ilda file ready it just need to be optimized.
    I just keep waiting...
    also on monday my new soundcard dac with audiolase will be here.

  10. #10
    Join Date
    Feb 2010
    Location
    Melbourne, Australia
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    Default

    Looks OK to me.

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