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[Thomas Bishop]

It sounds like you have some DMX addressing overlays.  If they work fine individually then they work; it's something else in your system.

[Mark Holley]

Very strange...  Well I'm certain all the addressing is proper, I've checked it more than once. and I'm only using channels 1-16 so it's quite easy to keep it straight so to speak... they worked for a while on ch 1, but when i switched them to ch 5 which is where they normally sit, they faded to black upon inserting the DMX cable, after that, they wouldnt work on any channel... only other thing I can think of is Im running this entire rig in my garage... maybe Im pulling to much draw on the circuit... i dont know... other cans work fine just these two are screwy...  There's a fair amount of fixtures on two seperate circuits, but not really all that much.  12 par 36, 4 250w color changers, 2 250w scanners, 6 LED par64, 2 color bars, spli between 2 circuits, then 8 par 38 on another circuit...  when i pull the 2 screwy cans inside and put them on a little controller its just the 2 and they seem to work... Im baffled. ... The dip switchs or the board tey are on seems like it might be the source of the trouble maybe?

It sounds like you have some DMX addressing overlays.  If they work fine individually then they work; it's something else in your system.

[Mark Holley]

a couple of pix of the rig im working with... small school but eventually I'll take out the things that are a waste and replace with things that matter.

[alan hamilton]

Some of the fixtures have reverse polarity? I'd fix that internally on the cans if at all possible... Get all the cans the same polarity. Even if all the fixtures were the same polarity, and that was backwards of your console at least one polarity reversal at the first of the chain fixes everything.

It's a little suspect that fixtures from the same manufacturer would be backwards of each other intentionally... so I'd expect wrong solder or a connector internally that can be inserted wrong or something.

So I'd make absolutely sure while comparing fixtures they were all wired the same internally as far as DMX goes. And make sure pin 1 is always the shield. Don't trust colors, follow the wires.

At that point you at least have a consistent baseline with the fixtures and no variables like needing random polarity changers (and keep in mind IF you turn around the polarity ENTERING a fixture it will STAY that polarity for the rest of the chain until you change it back on some other fixture). Reverse in means it's now reversed on the out.

So get that all straight first...

Then toss our the mic cables and get proper DMX cables for every fixture and test your cables for continuity and polarity. Mic cables work until they don't. You'll likely never figure out the rhyme or reason why the mic cables you've been using with your DMX suddenly have an issue some place or some time... but it WILL happen eventually... somewhere... even in circumstances where you'll swear you did everything the exact same way last time and it was fine. Just understand mic cables aren't designed for data and in some circumstances they will cause you issues. In other cases they will do the job... until they don't.

[Mark Holley]

All the LED pars are reverse polarity... all came from same place.  I have 6 of the barrel type polarity flippers and basically flip the pol going itno the first of three cans on one side of the rack, then flip it back to go to a series of normal fixtures, flip it again to go into the other 3 LED pars.  I'm guessing from all the input from the good folks here, that it's an issue with the cold solder on the XLR jacks on those two cans, maybe not, but tried everything else...

I never realized that a XLR cable was that much different than DMX.. I mean I knew you could use either but were supposed to use DMX    Just so strange that they work individually on a small 6 channel board with just one XLR cable going to it, but move it to the rig with everything else, (no matter where in the chain I place the can) and it works for 3 seconds then fades to off... (and also notice that they kinda randomly flicker after that, I mean a few random diodes flicker on and off.  Yet all other cans remain functioning normally while the bad ones are in the chain, so the signal is continuing on down the line. 

Can't really change the polarity inside the can itself, can't get to that area of the board (it's encased in plastic box type thing) 

Thanks so much for all the help and insight... I'm still trying to get them to work, very frustratin

Some of the fixtures have reverse polarity? I'd fix that internally on the cans if at all possible... Get all the cans the same polarity. Even if all the fixtures were the same polarity, and that was backwards of your console at least one polarity reversal at the first of the chain fixes everything.

It's a little suspect that fixtures from the same manufacturer would be backwards of each other intentionally... so I'd expect wrong solder or a connector internally that can be inserted wrong or something.

So I'd make absolutely sure while comparing fixtures they were all wired the same internally as far as DMX goes. And make sure pin 1 is always the shield. Don't trust colors, follow the wires.

At that point you at least have a consistent baseline with the fixtures and no variables like needing random polarity changers (and keep in mind IF you turn around the polarity ENTERING a fixture it will STAY that polarity for the rest of the chain until you change it back on some other fixture). Reverse in means it's now reversed on the out.

So get that all straight first...

Then toss our the mic cables and get proper DMX cables for every fixture and test your cables for continuity and polarity. Mic cables work until they don't. You'll likely never figure out the rhyme or reason why the mic cables you've been using with your DMX suddenly have an issue some place or some time... but it WILL happen eventually... somewhere... even in circumstances where you'll swear you did everything the exact same way last time and it was fine. Just understand mic cables aren't designed for data and in some circumstances they will cause you issues. In other cases they will do the job... until they don't.

[duane massey]

Mark, it seems that you have an issue between the controller and 3 specific fixtures. Try setting ALL fixtures to DMX 001, all hooked up to the bigger controller. IF you still have the problem, switch the same rig over to the 6-ch controller. IF the problem disappears, there is something very odd between the controller and the fixtures; I'm guessing that the dmx translator IC's in the fixtures are not the best quality and the dmx signal from the controller is just weak enough to be an issue. I'm not real comfortable with this guess, but I'm not actually there.
IF the problem goes away when you set all fixtures to 001, there is probably an issue with the fixture's dmx address section, but I have no realistic solution here as you will get no tech help from the company.
Keep poking at them, maybe we can collectively figure it out.

[Mark Holley]

THanks Duane....
The help has been, well, very helpful for sure!

I think your assessment of the DMX addressing area of the fixture is probably correct. The controller is the AM DJ stagedesk 16 that I have all the LED cans on, as well as 2 chauvet color strips. I run 8 conventional cans , 2 intimidators, and 4 AM DJ color changers on an elation stagesetter 8. Both boards seem solid and produce no problems to speak of... occasionally a fader will be all the way down but a conventional can will be on slightly untill I nudge the fader up slightly and it goes off completely. Occasionally the readout on the stagedesk will not settle on a value completely and a nudge to a fader will clear it up but other than that still pretty solid. I'm going to try your idea of the three troublemakers on the stagedesk  by them selves at ch1 then same cables, same address on the little elation 6ch board. I'll report back what i find....

I will say this though that when i open the back on the bad cans and press down on the dip switch connector on the circuit board it has cleared it up in the past at a gig... now the same problem is happening but to multiple cans, so might be safe to assume that this brand of fixture just fails in that area...  all bad cans still work in stand alone mode (i.e. setting a static color with dips)

Thanks again for the help Duane, and all others that have offered their insight....
I sold a 10mw laser and 2 mini LED movers today so I've a little scratch to buy a replacement if these dont eventually play nice

Mark

Mark, it seems that you have an issue between the controller and 3 specific fixtures. Try setting ALL fixtures to DMX 001, all hooked up to the bigger controller. IF you still have the problem, switch the same rig over to the 6-ch controller. IF the problem disappears, there is something very odd between the controller and the fixtures; I'm guessing that the dmx translator IC's in the fixtures are not the best quality and the dmx signal from the controller is just weak enough to be an issue. I'm not real comfortable with this guess, but I'm not actually there.
IF the problem goes away when you set all fixtures to 001, there is probably an issue with the fixture's dmx address section, but I have no realistic solution here as you will get no tech help from the company.
Keep poking at them, maybe we can collectively figure it out.

[DanGlass]

If your controller (dont know what your using) has the ability to patch individual channels then you could buy any other fixture and patch the channels accordingly.  Meaning that your current fixtures have intensity on channel 1 but another fixture could have the intensity on channel 4.  If your using an inexpensive slider controller than you will be stuck with replacing them with fixtures of the same channel lineup.  Moving channels around in the patch of your controller can be a little challenging and time consuming on the setup but once you wrap your head around it you will see all of the possibilities and you wont have to delete any of your exisiting programming. 

[John Strzalkowski]

DMX is just data, no voltage involved

I understand what you meant by this, however I feel I must correct. There is voltage involved. If you were to read DMX on a meter, typically you'll find ~3.5V. However the voltage level does not vary depending on output. (You will not get a lower voltage when trying to dim something, or change a parameter).

Sorry, but I couldn't sleep at night thinking about that sentence in the exact way you said it. Nothing personal.

[duane massey]

John, no offense taken. Now get some sleep.

[ProSoundWeb Community]