Control/Dimming Leprecon VX-2400 Series II Strobing Issue

[ndp]

We're having a strange issue with a 36-channel custom Lep dimmer rack we have. I've sent a few emails to Lep but haven't heard anything back yet. The rack is well out of warranty (2006 build date) but I'm still interested in getting it fixed.

The rack has a DMX in and a DMX passthrough. All the dimmer packs are wired in series, from the DMX in panel connector to all the packs (1->-2->3) and finally from the 3rd pack to the DMX passthrough.

When the DMX passthrough is used on the rack and DMX data is sent in the “DMX IN” port, channels adjacent to the channels being sent strobe and have their values rapidly fluctuate. This leads me to believe that one of the processor/control cards in one of the three packs may be damaged. The dimmer functions appropriately and has no issues besides the rouge data present on the DMX passthrough connector.

Curious if anyone has thoughts on what could be going on. Thanks.

- Nick

 

[microstar]

Have you tried DMX in to only one pack at a time, then out that pack to the DMX passthrough connector? That would isolate which pack had a problem.
Give Leprecon a call if they haven't responded to email; I've always found them willing to help, even with their older stuff.

 

[RonHebbard]

We're having a strange issue with a 36-channel custom Lep dimmer rack we have. I've sent a few emails to Lep but haven't heard anything back yet. The rack is well out of warranty (2006 build date) but I'm still interested in getting it fixed.

The rack has a DMX in and a DMX passthrough. All the dimmer packs are wired in series, from the DMX in panel connector to all the packs (1->-2->3) and finally from the 3rd pack to the DMX passthrough.

When the DMX passthrough is used on the rack and DMX data is sent in the “DMX IN” port, channels adjacent to the channels being sent strobe and have their values rapidly fluctuate. This leads me to believe that one of the processor/control cards in one of the three packs may be damaged. The dimmer functions appropriately and has no issues besides the rouge data present on the DMX passthrough connector.

Curious if anyone has thoughts on what could be going on. Thanks.

- Nick

@ndp Do you have a terminator on the end of the DMX line?
Toodleoo!
Ron Hebbard

 

[cbrandt]

These racks always "don't play very well with their neighbors". We have 8 in our inventory, and they are rock solid. BUT, especially newer dmx fixtures just don't like being after them in the dmx chain. We generally use optos to keep everything nice.

DO NOT PUT A TERMINATOR IN! This is one of the few items that I've worked with that a terminator will make the problem worse, not better.

It is also VERY easy to power down, and remove the entire control card from these racks. There are four screws on the front panel, and then the entire control card is pressure fit into the rack. Only do this with the rack completely powered down and removed from power. Once you've removed it, you can then power it back up with the card out, and see if the problem goes away.

We love these racks because they are rock solid, and easy to service. They can just be a little eccentric on DMX.

 

[Amiers]

Dropping in an opto splitter will definitely help you figure out which rack is being weird. Could also be a bad cable. Tear it all down and test individually then rebuild and test as you go.

 

[brucek]

I'm placing my bets on a bad rack jumper or a bad '485 receiver chip in one of the packs that pulling down or ringing one of the lines. If you have access to a scope, try looking at the DMX signal to make sure you aren't getting getting any reflections or too much overshoot.

I assume this is address independent - i.e not on the controller side.

 

[ndp]

Thanks all for the advice. Heard back from Lep today as well. Going to try some of these suggestions tonight and will keep you posted.

- Nick

 

[ndp]

Well, I'll be darned. Could not get the issue to reproduce. Back into service, until it happens again...

Thanks for all the advice nontheless.

- Nick