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Thread: Work around for intermittent problem with beam suppression on badpip driver ?

  1. #1
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    Default Work around for intermittent problem with beam suppression on badpip driver ?

    I'm having an issue with the badpip driver. While at home everything works fine, however when setup at shows, often the beam suppression doesn't work as it should and the blue comes on when at idle. I suspect is something to do with inductance with longer cable runs, likely only takes 0.1V or less to take the driver out of beam suppression or could be a different cause for the issue.

    As the driver outputs only 2 Amps, but capable of 2.5 Amps with threshold at 500mA, in order to get full power out of it I need to see the threshold way higher than I normally would. If set that way, of course it lights up quite brightly when this happens, if I set it to proper threshold it's a bit less annoying but still a problem.

    As the is no bias setting on the badpip driver, I'm unsure of what would be the best way to fix this. Thinking potentially a small resistor or perhaps a schottky diode to drop the voltage on the colour line by 0.1V or perhaps a tiny bit more ?

    I'm just wondering if anyone else has ran into this issue and how did you fix it ? If anyone has any advice for me would be greatly appreciated.

    Thanks,

    Miles

    Edit : I just wanted to ad that I'm not against the idea of replacing the driver altogether, but have an important show coming up in a few days and would like to fix this if possible, even if just a temporary fix.
    Last edited by m0f; 08-23-2014 at 02:58.

  2. #2
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    Or could it be a floating ground type issue ? Only one of two lasers has the problem, the other remains off all of the time. I'm using a stanwax ilda interface board, so db25 ports go directly to it and in testing I've bypassed my scanfail so colour lines directly go out to the lasers.

    The blue is typically the only one that is a problem, however my red does to the same thing at times as well, both running from a single badpip quad driver.

    A couple of other minor issues with this laser which may hint towards the problem. I am having a problem with the e-stop with this particular ilda interface board, for some reason with longer cable runs, the laser refuses to start when using the e-stop, with my other laser with same interface board everything works as it should. Also with this laser the led on my e-stop does not go red, and green is very dim. When hooked up to the other laser, red / green led work as they should.

    It's been this way since first built, and I've been meaning to purchase another interface board to improve the e-stop functionality and led issues, but I am wondering if there may be some voltage leaking to the colour lines if the interface board is having issues, or possibly another internal issue that is causing the interface board not to work as it should. I suppose both could be a possibility.

  3. #3
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    Could it be potentially beneficial to tie R- B- G- colour lines to ground after the ilda interface ?

  4. #4
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    Problem solved I think. As it's intermittent in nature only time will tell, but I found an issue with a floating ground, which upon fixing seems to have resolved the issue. Can't be sure at this point but am 95%+ sure that was it. Another example of the importance of following a star grounding scheme.

  5. #5
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    Which software/DAC package are you using? I have the same thing happen on my Flexmod P3.3 with beam supression. I will see the flaxmod flick on every now and then, on all three diodes. I am using Beyond and it happens with my QM card and FB3s. Perhaps my grounding scheme is setting up a ground loop???
    Those who fail to grasp art are the ones who criticize it.

  6. #6
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    I am using Beyond w/ FB3's but I really don't suspect the dac or software. Firstly it seems to happen with software not loaded, as for the dac itself while it was steadily acting up last night I pulled the ilda cable from the laser and tested it, was right at 0V. Only once plugged into the laser, outputs from the ilda interface board were at 0.054V.

    I found my scanner power supply ground reference was at 0.25V, with the ilda board powered from it. Grounding the scanner power supply 0V to chassis ground did seem to fix the problem. I can't be sure as it was intermittent, but was acting up all night and hasn't since in testing.

  7. #7
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    Old news, but it bears repeating: wiring and grounding recommendations:

    http://www.pangolin.com/resguide12.htm

  8. #8
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    I've read that one many times But have traditionally preferred to keep my chassis grounds from mixing with my signal grounds as ground loops can be a real issue with some shows when unable to power all lasers from the same power source. However in this case had to tie it to chassis ground to solve the issue (so far so good, will know for sure soon as I have two shows this coming week)

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