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Thread: Feeble output from FB3

  1. #1
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    Default Feeble output from FB3

    I have a (Chinese) 1W RGB projector being controlled by an FB3. The laser's output is feeble compared to my other 1W (Chinese) running in DMX mode, and even a 600mW TTL. What gives?

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    Quote Originally Posted by smokeAndMirrors View Post
    I have a (Chinese) 1W RGB projector being controlled by an FB3. The laser's output is feeble compared to my other 1W (Chinese) running in DMX mode, and even a 600mW TTL. What gives?
    Have you proved full 1W output normal using a different DAC?
    leading in trailing technology

  3. #3
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    Quote Originally Posted by polishedball View Post
    Have you proved full 1W output normal using a different DAC?
    To be honest I just turned up to set up for a gig tomorrow, switched on and was a bit underwhelmed. I will try the laser in demo mode when I get going tomorrow - should at least verify I'm actually losing power or not through the FB3. But I should say that this isn't the first laser the FB3 has looked a bit faint on.

  4. #4
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    Meh, just found a couple of threads relating to this sort of problem. Pango say "blame the laser manufacturers"; experts say "simply build this piece of electronics" (that will not happen by tomorrow evening) and I sigh.

    Can't I just buy a laser that *works* without requiring a degree in photonics, dammit?!

  5. #5
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    I'm sure you have done this but just check when you set QS up you set it to TTL and not Analogue to ensure you're getting the full 5 volts out (its quite easy to set the wrong one as the buttons don't show terribly well when pressed - I'm feeding this back to Bill as we speak).

    Otherwise it sounds like the dreaded impedence problem.

    BTW, from memory doesn't one of Rob's (Stanwax's) colour boards correct this problem? Might be worth a check if you want an off the shelf solution without having to build circuits yourself.
    Last edited by White-Light; 10-16-2010 at 03:01.

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    Is your other 1W projector RGB or single/dual colour? How does that perform on the FB3 conpared to standalone?

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    The other projector is RGB (900mW total). Its output is brighter (subjectively).

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    Brighter when on the FB3? If so, it could be that the newer projector's laser modules don't respond so well to the rising signal from the FB3 than the 900mW one. This might be in conjunction with impedance issues as stated previously.

    How fast are you scanning? If 30kpps, try lowering it to 15kpps and see if it changes. If so, it does point to the lasers performing poorly under fast modulation

  9. #9
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    I dropped the scan rate to 17kpps for the show. The beams were barely visible :-(

    I realise it's not entirely Pangolin's fault, but somehow I feel that Bill's attitude - "it's not us that is at fault, it's the way other people make their projectors" is not exactly reasonable. Or even sane.
    Last edited by smokeAndMirrors; 10-17-2010 at 13:36.

  10. #10
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    Is it possible to build sort of buffer to go between the DAC and the laser to help this? If so, maybe that is something that should be added to all DACs. Since there are only a few DAC makers and a lot of laser makers, it would make sense to push the cure to the DAC makers instead of trying to fix the rest of the world. But again, is that even a possibility?

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