DMX Issue

[cmgunn]

Hi,

About 2 weeks ago I started having some problems with a Martin Mac 550 and an Elation Power Spot 575 switching and flashing when connected to DMX. Both fixtures work fine in test mode. I have tried pulling the fixtures down and connecting them directly to the console, even tried different addresses and consoles. The problem remained. They went down within a day of each other. What would cause this? The problem seems to be with the fixtures themselves.

 

[Tex]

Have you tried connecting each one directly to the console individually? Do they behave the same when not daisy chained? Is the run terminated?

 

[cmgunn]

The run is terminated. Both have been connected directly to both a Maxxyz console and a PC running lightjockey with nothing else plugged in.

 

[cpf]

Did they both stop working right at the same time? Were they both in use, or in the same place at that time?

 

[cmgunn]

Did they both stop working right at the same time? Were they both in use, or in the same place at that time?

One stopped working during a show Saturday night. The other the following morning. They stopped responding on power up, not during the show. I also had a Mac 300 the week prior sent off for repair. When it would tilt past a certain position, it would swing around then come back. A few days later it died completely. Possibly something related to that?

 

[silicsound]

I doubt that your problems are related to the recent repair of the Mac 300. The Mac 300's problems are most likely caused by internal components, which would not affect the other lighting instruments. From the sound of things, it seems the likely culprit is the DMX signal.
Did the two instruments die completely, or do they only have "issues"? And where were they on the DMX Chain? And what is the total approximate length of the DMX cable run? Also try removing the terminator, If the problem goes away, then you likely have a bad cable somewhere.

 

[cmgunn]

I doubt that your problems are related to the recent repair of the Mac 300. The Mac 300's problems are most likely caused by internal components, which would not affect the other lighting instruments. From the sound of things, it seems the likely culprit is the DMX signal.
Did the two instruments die completely, or do they only have "issues"? And where were they on the DMX Chain? And what is the total approximate length of the DMX cable run? Also try removing the terminator, If the problem goes away, then you likely have a bad cable somewhere.

There's probably a few hundred feet of cable run. The 550 is about in the middle of the chain, the 575 is first in line. I've tried removing the fixtures from the dmx chain and hooking them directly to the console with a 15ft cable and got the same result.

 

[cmgunn]

To clarify, I have tried the following

• Hooked the fixtures to the console individually, with nothing other than that one fixture connected. Still had the problem.
• Tried with and with out the terminator, no improvement either way.
• Tried a different console, same problem.
• Tried different addresses, same problem.

As stated above, both fixtures work in test mode. Perhaps the DMX input on these fixtures was fried somehow?

 

[silicsound]

It does sound like the opto's may have gotten fried somehow, but that would be very rare. If you haven't already, try moving the DMX cable away from any electronics or power cables. Also were there any changes in the system around the same time the problem started? Correct me if I'm wrong, but from my understanding only the "light" is freaking out on you, but none of the other parameters like pan and tilt are going crazy?

 

[cmgunn]

It does sound like the opto's may have gotten fried somehow, but that would be very rare. If you haven't already, try moving the DMX cable away from any electronics or power cables. Also were there any changes in the system around the same time the problem started? Correct me if I'm wrong, but from my understanding only the "light" is freaking out on you, but none of the other parameters like pan and tilt are going crazy?

The 575 doesn't respond at all. It does a reset as soon as a DMX signal is presented, then begins to twitch (P/T only) nothing else responds until we remove the DMX signal.

The 550 responds somewhat, but everything, gobo wheels, color wheels, misc effects etc stutter and twitch when a DMX signal is present. The only change to the system was the removal of the Mac 300. The 550 had service that week, so it's understandable that something could have been damaged. As for the 575, this is the first non lamp related issue we've ever had with it over the 4 years we've had it.

 

[silicsound]

The only conclusions I can come come up for your problems is, that you have a strange DMX signal; which is unlikely. There may have been a high voltage surge on the DMX line which fried the opto's; which would be unlikely. There might be a timing issue, try changing the baud rate on the console, try and see if that fixes anything. Otherwise, it sound's like you got a bunch of ghosts/gremlins haunting you system. Out of curiosity, are any of the DMX lines connected though a house system, conduit, PSU, opto-splitter or any thing that might have a chance of short circuiting?

 

[cmgunn]

The only conclusions I can come come up for your problems is, that you have a strange DMX signal; which is unlikely. There may have been a high voltage surge on the DMX line which fried the opto's; which would be unlikely. There might be a timing issue, try changing the baud rate on the console, try and see if that fixes anything. Otherwise, it sound's like you got a bunch of ghosts/gremlins haunting you system. Out of curiosity, are any of the DMX lines connected though a house system, conduit, PSU, opto-splitter or any thing that might have a chance of short circuiting?

Our run goes through a conduit in the floor, then up to the amp room. There is an opto-splitter which is much later in the chain. My biggest area of concern is the dimmer packs. They put them on the same run, but they are LMX. They have a DMX converter box, but since LMX does run power over the line, if something shorted in the converter box, it would certainly be enough to fry everything in the chain.

 

[silicsound]

Unfortunately I can't solve your problem without a hands-on inspection, but from the sounds of things you may have a serious problem somewhere in your DMX run, which may cause future problems. The only thing I can suggest is that you hire a professional that is experienced in handling DMX gremlins and send in your fixtures to be repaired.
Also I've worked with a lot of systems that had slight twitch in them, and some times there is nothing you can do about it, except work around it. But your problem seems to be much more advance.
In the mean time, I would suggest by-passing the conduit and opto if you can, because it does sound like something got short circuited and fried the opto's. But I would wait until some of the more experienced members of CB weighed in on the topic.

 

[cmgunn]

Unfortunately I can't solve your problem without a hands-on inspection, but from the sounds of things you may have a serious problem somewhere in your DMX run, which may cause future problems. The only thing I can suggest is that you hire a professional that is experienced in handling DMX gremlins and send in your fixtures to be repaired.
Also I've worked with a lot of systems that had slight twitch in them, and some times there is nothing you can do about it, except work around it. But your problem seems to be much more advance.
In the mean time, I would suggest by-passing the conduit and opto if you can, because it does sound like something got short circuited and fried the opto's. But I would wait until some of the more experienced members of CB weighed in on the topic.

I did have an installer come out and look at our system. It was put in before I got there and we don't have a map, but suspect it all needs to be rerun anyways. We are unable to bypass the conduit as there is no other way for the run to reach the stage. I will remove the splitter, as that was only installed when we rented additional fixtures for a show and is no longer necessary.

 

[silicsound]

You don't have to by-pass the conduit, just run a new line. I suspect the old line's jacket may have been damaged and the wire was short-circuiting to something. Although rerouting it would reduce interference from other lines in the conduit.
Just to note by-passing everything isn't meant to fix anything, it just a preventive measure to prevent more damage.

 

[cmgunn]

You don't have to by-pass the conduit, just run a new line. I suspect the old line's jacket may have been damaged and the wire was short-circuiting to something. Although rerouting it would reduce interference from other lines in the conduit.
Just to note by-passing everything isn't meant to fix anything, it just a preventive measure to prevent more damage.

On the fixtures themselves, is the opto on its own PCB or is it built into something like the main PCB?

 

[silicsound]

I would guess everything is on a single PCB, that way manufactures save 50 bucks or so on every light, but I don't have any personal experience with those fixtures. I would suggest sending the fixture in, because I can tell you from experience a DIY repair can go completely south in a couple seconds and cost you the full price of the fixture.

 

[cmgunn]

The reason I ask is because both 550's are in need of a new ballasts, and one needs a power supply as well. The price of 2 ballasts, a power supply and the main PCB would exceed the cost of replacement for both. But I will verify this with Martin before making a decision.

 

[cbrandt]

This is a long shot, but it COULD be that the software on those fixtures got fritzed somehow, and needs to be updated/reinstalled. You'd likely need an authorized technician for that. Seems odd that a Martin and an Elation would have that same problem at pretty much the same time.

 

[JChenault]

The only conclusions I can come come up for your problems is, that you have a strange DMX signal; which is unlikely. There may have been a high voltage surge on the DMX line which fried the opto's; which would be unlikely. There might be a timing issue, try changing the baud rate on the console, try and see if that fixes anything. Otherwise, it sound's like you got a bunch of ghosts/gremlins haunting you system. Out of curiosity, are any of the DMX lines connected though a house system, conduit, PSU, opto-splitter or any thing that might have a chance of short circuiting?

Wait. I'm confused.

I thought I heard the OP say that he saw the issue when he directly plugged the fixture into two different consoles. My assumption was that this was by running a short piece of cable from the console to the fixture. If that is so then I dont understand how the building cable could be at fault

Re reading the posts I am not 100% sure that you did not use the permanently installed cable in your test. If you use the permanently installed cable, I suggest you retest a faulty fixture by directly attaching the fixture to your two consoles. If it still fails try another cable. If it still fails I think it likely that your fixture is at fault