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Ghosting Lights

Discussion in 'Lighting and Electrics' started by lazor, Mar 6, 2009.

  1. lazor

    lazor Member

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    Location:
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    My theater had an Expression 3 that had a few things not working, like submaster 1 and 3 of the 5 E wheels. Our sister campus had an extra Expression 3 laying around (because they just got an ION, I'm very jealous) so we swapped the two boards out. However, now almost every time I turn the board off at the end of the day, I go back out into the theater to find one or two lights on. This has happened to me before in other venues and I know that after a few minutes it will realize it's not actually getting a signal and turn off but with this board it happens nearly every time. Does anyone know what causes this and if there is any way to fix it?
  2. TechnicalAngel

    TechnicalAngel New Member

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    Location:
    Massachusetts...blech
    I know what you are talking about haha...lights randomly turn on in our theatre too. One time in the middle of our "Cristmas Carol" play, during a black out a random light turned on. (my stage manager was not happy with me).

    Plus on top of that we have a ghost up in our grid.....*is scared to go up there*
  3. icewolf08

    icewolf08 CBMod CB Mods

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    Usually you can change how your dimmers respond to a loss of signal, but it sounds like your console is just sending out some bad data on shutdown. Out of curiosity, what happens if you take everything to 0 on the console then unplug the DMX and then power off the console and plug back in? If the lights stay off then it is an issue with the console. If the lights come on then there are other things to look at.
  4. Grog12

    Grog12 CBMod CB Mods Premium Member

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    Another easy fix (though more of a band-aid than anything) is make sure you're pulling down the Grand Master as well before you shut down.
  5. xander

    xander Active Member

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    Occupation:
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    Pulling down the Master isn't going to do anything if it is the console sending bad data on shut down--assuming all channels are released when shutting down.
  6. derekleffew

    derekleffew Senior Team Senior Team Premium Member

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    The cause is that during shutdown one last bad packet is sent out over DMX. The way to prevent it is to release all channels, clear all faders, bring all subs and the GM to zero, then unplug the DMX before powering down the console. I've also found that turning the console back on, then off again, seldom has the issue re-occur.

    As you said, most dimmers have a user-definable "hold last look," which, unless set to infinite, will take the lights out eventually.

    There was more discussion on this topic on the ETC Forum at Dimmer Ghosting with an Expression 3 Console - Electronic Theatre Controls.
  7. xander

    xander Active Member

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    Occupation:
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    Like it has been stated, the easiest way to avoid this is to unplug the DMX cable when shutting down. So set all levels to zero, meaning clear the faders, release channels, subs, and parked channels, and then take out the cable. I am not sure why you wouldn't be doing all of this anyway, so the only added part is the unplugging of the cable. There is no need to bring the Master down if you have cleared everything through the above methods.
  8. Grog12

    Grog12 CBMod CB Mods Premium Member

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    Its called redundancy. Its one more place to try and help keep bad packets from leaving the board.

    I've worked on boards that if you didn't pull the GM down it would send out the bad packets. I've worked on ones that it didn't matter.

    Its one more thing to do to prevent bad packets from turning on your lights when you want to leave.

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