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Lightronics TL-2448 board/Leviton D4DMX prob

Discussion in 'Lighting and Electrics' started by saxaphool, Mar 21, 2008.

  1. saxaphool

    saxaphool Member

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    I'm running a Lightronics TL-2448 board and Leviton D4DMX dimmers.

    We have 5 older Leviton D4DMX dimmers with only the DMX input/outputs, but the newer dimmers have the DMX and Microplex inputs/outputs.

    After a lot of frustration we discovered the newer dimmer packs are causing an irregular, intermittent dimming of the lighting units plugged into the newer dimmers. The older dimmer packs are running fine.

    We've swapped out the newer dimmer packs and the problem it consistent with all of them so far.

    Running the newer dimmers in programmed chase mode(non-light board controlled) the problem seems to go away.

    Any ideas?

    Phool

    P.S. Our show is in 2 weeks
     
  2. Footer

    Footer Senior Team Senior Team Premium Member

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    Don't know if this is possible, but try slowing down the DMX refresh rate on your console. Also, make sure the DMX chain is terminated and all that good stuff.
     
  3. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Maybe something in this thread will help.
     
  4. saxaphool

    saxaphool Member

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    <Maybe something in this thread will help.>

    Yea, I saw that thread...didn't seem to tell me much, other than not to buy those dimmers

    <slowing down the DMX refresh rate>
    can't seem to find a way with this light board, have the manual, but no mention of that

    <make sure the DMX chain is terminated>
    yep, terminated and still doing the same thing

    with one of the offending lights up, other lights(which aren't turned up) on the same dimmer will flicker on, and you can see the red LED "channel" flicker as well
     
  5. TimMiller

    TimMiller Well-Known Member

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    have you tried running the new dimmers to the lightboard by themselves? Do they still flicker? The older ones may be doing some weird MPX glitch. I have seen it happen before. You may be able connect the new dimmers than the old ones and things may be happy. Also you may have a bad cable between the old dimmers and new ones.
     
  6. soundlight

    soundlight Well-Known Member

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    Try isolating the problem - take the controller and the dimmers down, and plug each dimmer pack one by one in to the board and see which dimmers have problems without any external factors.
     
  7. saxaphool

    saxaphool Member

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    <have you tried running the new dimmers to the lightboard by themselves?>

    Yes, this was one of the first things we tried. We had a couple of "new" dimmers we had not hung yet and tried those independently and the same problem occurred.

    <Try isolating the problem - take the controller and the dimmers down, and plug each dimmer pack one by one in to the board and see which dimmers have problems without any external factors.> haven't tried this yet

    I talked to Lightronics yesterday and they seemed to think it was a channel re-patching issue, and recommended going 1 to 1 on my channels with no re-patching. We did this yesterday/last night and the same problem is occurring. Some dimmers are worse than others.
     
  8. LD4Life

    LD4Life Active Member

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    I know this may sound stupid, but you aren't trying to run DMX and Microplex in the same chain are you? About the same problem as using DMX cable and XLR cable in the same chain.
     
  9. David Ashton

    David Ashton Active Member

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    try reversing pins 2 and 3 on the control, the symptoms are compatible with a phase reversal somewhere.
     
  10. saxaphool

    saxaphool Member

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    <I know this may sound stupid, but you aren't trying to run DMX and Microplex in the same chain are you?>

    nope, I'm presently about to hang myself with my microplex cable

    <try reversing pins 2 and 3 on the control, the symptoms are compatible with a phase reversal somewhere.>

    your the second person to mention this... a friend i called asked if there was a phase switch on the board.....gonna give this a try
     
  11. saxaphool

    saxaphool Member

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    Well,

    (knocking on wood)

    On a hunch I moved all the old dimmers to the end of my DMX line, and the flickering problem "seems" to have gone away.

    (fingers crossed)

    Thanks for all the suggestions
     
  12. JD

    JD Well-Known Member

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    If that worked then you have a problem with noise on the DMX line. (The position should not matter if the DMX is solid.) The dimmers may have a different tolerance level of the noise and for some reason the signal is degenerating. Check your cabling and verify that your terminator is working. Look for any connectors where pin 1 and the case may be connected together. (They should not be.) Also make sure nobody substituted a mic cable in there!
     
  13. saxaphool

    saxaphool Member

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    well, my hunch didn't work, we still have a slight "flicker" on several dimmer packs, and we're basically living with it...it's beauty and the beast...so we're saying the wiring in the castle is kinda old

    levitron has shipped our replacements, but we haven't had the time to swap out (dress is tonight)

    we got in a DMX tester and the board tests fine with out anything attached, and the end end of the line tests fine as well. On an interesting note, with the old non-programmable board where everything works fine...the DMX tester says there's a problem..... so go figure
     
  14. JD

    JD Well-Known Member

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    Yea, if the problem is still there, then you are back to square one.

    A DMX tester will tell you how your DMX is broadcasting, but it can not tell you how well the packs are listening. In DMX, a sync signal is sent, then the packs wait through all 512 channels, hopefully locking the data from the brief time period where their programmed channel is located. In other words, it is asynchronous between the clocks. It could be the pack's own timing is off, or a design compromise was made so that the system is switchable between formats that is having some unexpected results. Is the problem the same on all addresses? In other words, if you set the packs to channel 1, then set them to channel 400, is the problem the same? (probably is, but would point to a design problem if not.)

    Interesting that your old board tests bad but the packs work ok with it. (did I get that right?) Could be the board is a little loud (too high a signal level) and the new packs are a little deaf.
     
  15. saxaphool

    saxaphool Member

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    yes, I originally had my dimmer packs set 11,21,31,41,etc starting addresses(mostly for my own sanity in setting things up)...then later reset all the dimmer packs sequentially1,2,3,4,5,6,7,etc.

    the problem remained pretty constant


    yes, you are correct....we thought that quite humorous as well

    the problem only seems to effect a few dimmer packs...we've tried swapping out dimmer packs, totally isolating dimmers/cables, all to no avail

    I've finally given up tryin to fix it with dress tonight and 5 shows this weekend... it's minorly irritating, but not overly detracting

    it's a HS show, and to be honest, a few flickering lights is going to be the least of the probs with this show
     

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