moving light fixture level changes dim other channels

I'm having a problem with an Express 24/48 console.  I am running a Martin MiniMAC patched to 10 channels, plus about 40 other stage lights.  When I change some levels on the fixture--either with faders, trackpad, or by playing back a cue (pan/tilt and intensity/strobe seem to be the worst offenders)--the other lights that I have on stage flicker.  This even happens if the MiniMac is not even plugged in to power or DMX. 

It seems that just sending changes to fixture-patched channels causes the flicker.  Lights that are on dim slightly several times while the fade (manual or automated) is happening.

I didn't check to see if it makes a difference with or without focus point references (I have both).

Any ideas why this is happening or what I can do to stop it?  Someone suggested that the CPU is just getting bogged down.

Thanks

  • Which firmware version is the Express running?

    The latest is 3.1.1, and it's definitely worth upgrading if you aren't already there - direct download link.

    Do you have a DMX tester to look at the DMX output directly?

  • I suspect the most important information is the path(s) data takes from your console to the MiniMac and to your other dimmers. 

    Is the DMX to the MiniMac coming out of the DMX 513-1024 port on the console and the DMX to the stage dimmers coming out of the DMX 1-512 port?  Or is the MiniMac in the DMX chain between the Express and the dimmers?  Or is there another arrangement I haven't mentioned?

    When you disconnected the MiniMac and still saw the problem, were the control cables for the new fixture still connected at the console end?  Are the new cables proper DMX data cables or is there a possibility that they are standard 3-pin microphone cables?

    One other piece of info that might prove useful is knowing what type of dimmers you're working with.  Different dimmers can respond differently to data problems.

  • Thanks for the suggestions!

    Tried upgrading the software (from 3.0.4 to 3.1.1).  Didn't help, but probably needed to be done anyway.

    Tracy, your questions prompted me to look at the cabling which is all over the place.  Splitter box, mic cables, 3-pin, 5-pin.  But I did have one long run of good shielded DMX cable that I ran from the second DMX port which seemed to do the trick.

    I had to hack and slash my way around the "not enough dimmers" error when trying to re-patch the fixture--as well as figure out that what started on dimmer 59 ended up on dimmer 58.  But it's working!

     

    Thanks again for your help.

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