Control/Dimming Leprecon MX2400 Flicker issue

Hi everyone! Our local theater group just purchased two new Lepricon MX2400 analog/digital dimmer packs and are using them with a Teatronics analog controller. At lower dimmer settings, the lights connected to the dimmer packs flicker randomly. Has anyone run into this issue before? It's driving us crazy. The problem did not exist with the old analog dimmer packs.
 
Might want to check your analog cable connectors, and see if there's a dirt/corrosion issue (unplugging and replugging several times often self-cleans the rectangular cinch-jones connectors used on the Leprecon equipment). Also, check the output of the console, and see if you're outputting 0-10 volts dc, which is what the MX dimmers will be looking for. Not all analog systems used the same range, although problems with this usually manifest themselves in terms of dimmer curve, not flickering.

Dirty or bad faders in the console may also be an issue. Does the problem follow if you start swapping packs around, or put the old dimmers back in place?

Since you're not mentioning problems like dimmer coming up out of sequence, or levels changing as additional dimmer are added, I'm assuming that your pinouts on the control cabling is correct.
 
Thanks for the reply. I don't think it's dirty faders; the controller works fine with the old analog dimmer packs. At low levels, the lights randomly pulse; this is common to both new Lepricon MX2400s. This seems to be most noticeable at lower light levels, where dim lights will pulse brighter for a portion of a second. Channels 1 & 2 are flickering at the same rate; channel 3 & 4 are flickering at a different rate, etc. I'm planning to look at the inputs and outputs with a scope; transitions are too quick for a voltmeter to register.
 
Channels 1 & 2 are flickering at the same rate; channel 3 & 4 are flickering at a different rate

This is a bit odd - last I knew, the dimmers are phased consecutively, not in pairs, ie; 1 is X, 2 is Y, 3 is Z, 4 is X, etc., so it's unlikely that this would be a per-phase timing issue.

I'm assuming that you've got more than a couple hundred watts of load on each channel, extremely light loads can ghost oddly.

I'd recommend calling Leprecon at (888) 422-3537, and asking them what they think might be happening. If they're less than a year old, they will still be under warranty, and Leprecon is generally very good about making things right.
 
If you are not using the DMX inputs, either configure the pack to ignore them, or stick some terminators in the female outs. (In and out are wired in parallel.) Probably not the problem, but why listen to an empty input.

This pack has a very low minimum load (15 watts) so I don't think that is the issue.

The pack has an adjustable analog range. Could be the problem is in the board and was always there, but was too close to the black level for your old packs to respond to it. If you unplug the board and the problem goes away, that is a pretty good indicator.

Since the synchronized flicker crosses over two phase legs, I don't think it is related to any noise throwing the ZVC detectors in the pack.
 
Thanks for all your suggestions. I did call Lepricon and they gave me some helpful suggestions. I also did some further looking with a scope on tyhe dimmer pack outputs and found what looks like a noise spike on top of the AC waveform (which is triangular); as the spike changes amplitude, the lights flicker. I'm going to try using a battery or power supply on the input and see what happens; voltage was steady from the controller but I want to make sure that I can isolate the problem to either the controller or the packs. I found that at higher level outputs (approaching full brightness), the dimmer pack output approaches a sine wave output (with a little noise on the shoulders) and the flicker is not noticeable.:)
 
I just had the same issue with two of my ULD 360 packs.
These are ULD-360, 20A, HP, Duplex.
At 'full up', from any of my console, I get a random flicker on all channels and sometimes lose DMX totally.
Any suggestions?
 
That sounds more like a cable problem than a dimmer problem - random flashing or no control at all tend to suggest incorrect cable type or reflections. Are you using cables intended for DMX? Have you tried terminating? Are the cables in good repair? (broken shield leads or pins = no shield at all) The ULD dimmers have menus that allow you to bring up channels at the pack itself, are things stable when you do that?
 
All cables, controllers and power in good order. I shop tested with the same cables and controller, then used new cables and then used new cables and new controller.
No change.
Terminated and non-terminated, no change.
Tested with controller and then manually tested with the packs menu, no change.
Leprecon is on holiday so I will get to them come next week.
 

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