Lighting Problem

[DHSLXOP]

Hi Everyone... (this is lenghty, just so you know)
So...today I got to work at my camp (where I run all things technical) and noticed that the stage lights were on but were at a very low intensity (probably about 20-25%). I walk into the booth and notice that the light board is off completely. So I thought, "maybe someone just turned off the board to quickly and didn't bring the master all the way down in time." (cause that sometimes happens--where the lights stay on after the board is off)...so I power on the board and first try to raise and lower to see if the master does anything, but it doesn't. So I then bring up the dimmers and master and the lights go to full intensity. When I brought the master down though, the lights went back to their 20-25% intensity. I told the building operations director who tried the same things I did and, again, nothing happened...he then went backstage and looked at the dimmers. He turned them off which obviously took the intensities to 0. But as soon as he turned the dimmers back on, they went back to 20-25%. For now, he has decided to keep the dimmers off, since he doesn't want the bulbs to burn out, but since we need lights at camp for our assemblies, I wanted to know if anyone knew what the problem would be and how to fix it. The board is and EDI Minstrel and the dimmers are made by EDI but I'm not sure of the exact make. One other thing to note is that there have been electricians in the the theater who have been preparing to hang chandeliers (sp?) and have been running cable to the circuit breakers..we think that this may have something to do with it.
Thanks everyone in advance for your help, and sorry that this was so lenghty.

[zac850]

Hum, interesting problem.

What kind of dimmers are these? If they have some sort of brains/processor in them (CEM) check to see if you have a profile set that is keeping them at a glow. Some dimmers (even old analog dimmers) had a setting so that instead of the lights going completely out, you would have a glow. Look for that.

I used a similar console to yours at a community theater way back when, and sadly don't remember much about its operation. However, as a basic two scene preset console (even with the recordable scenes) you wouldn't have any issues of dimmer profiles being set-up.

So, to trouble shoot:
1) Check your DMX run. Try unplugging the cable from the lighting console and then turning the dimmers on. If the dimmers don't glow as they have been, you know the issue is with the console. If they do glow, you know the issue lies somehow with the dimmers.

I don't know what else to suggest sadly. I had several dimmers die on me, and I had to replace the SCR internally, but whenever that happened the dimmer fails either full on or full off, not at a 25% glow.

Is it possible that when the electricians were running around they did something that somehow let some voltage trickle into your system? I'm not quite sure how someone would do that though........

The fact that you can get control of the fixtures above 25% when you need to makes it sound like there is some feature somewhere that keeps the lamp warm, and that somehow that feature got turned on. Check your console and dimmers for something along the lines of 'warm up' or 'preheat' or something like that.

Good luck, let us know what it is!
Zac

[Grog12]

zac for the win.

The only other thing I could think of is they could be ghosting but that's a hellof a level for them to ghost at.

Is this outdoor theatre?

[gafftaper]

Yeah doesn't sound good. I've had a lot of trouble on campus here with an old EDI "dimmex" dimmer pack mounted to the wall. Every time we had a show in that space another circuit died, started ghosting, or changing intensities at random. We also had an EDI minstrel to go with it. After a lot of expensive service calls... we simply decided it's time to get a new dimmer pack.

[jklak]

We have a Lehigh system and we have had ghosting issues when there has been a power outage. There is a specific restart sequence that has to be followed for our system. You could have a similar situation if your electricians decided to just turn off everything rather than figure out which breakers they needed to turn off. You might check with your manufacturer to find out if there is a restart sequence.

[Footer]

Any architecture system in the loop? Try unplugging your DMX from the dimmers and see if that does anything, from the dimmers, not from the board. Also, to a full reset on the control unit.

[DHSLXOP]

Thanks everyone for your replies...here are answers to some of the questions and some more questions I have...

First off, the theater is not outdoors, but has been "overtaken" by the catering company who has put all their equipment in what used to be the storage/dressing room area. I doubt this has anything to do with it, but the dimmers are right behind some of this equipment.

Also, how do I unplug the dmx from the dimmers when the dimmers are the long stacks and all of the wires are in the walls?

[DHSLXOP]

Originally Posted by zac850

Hum, interesting problem.
What kind of dimmers are these? If they have some sort of brains/processor in them (CEM) check to see if you have a profile set that is keeping them at a glow. Some dimmers (even old analog dimmers) had a setting so that instead of the lights going completely out, you would have a glow. Look for that.
I used a similar console to yours at a community theater way back when, and sadly don't remember much about its operation. However, as a basic two scene preset console (even with the recordable scenes) you wouldn't have any issues of dimmer profiles being set-up.
So, to trouble shoot:
1) Check your DMX run. Try unplugging the cable from the lighting console and then turning the dimmers on. If the dimmers don't glow as they have been, you know the issue is with the console. If they do glow, you know the issue lies somehow with the dimmers.
I don't know what else to suggest sadly. I had several dimmers die on me, and I had to replace the SCR internally, but whenever that happened the dimmer fails either full on or full off, not at a 25% glow.
Is it possible that when the electricians were running around they did something that somehow let some voltage trickle into your system? I'm not quite sure how someone would do that though........
The fact that you can get control of the fixtures above 25% when you need to makes it sound like there is some feature somewhere that keeps the lamp warm, and that somehow that feature got turned on. Check your console and dimmers for something along the lines of 'warm up' or 'preheat' or something like that.
Good luck, let us know what it is!
Zac

I did try it already when the dmx was removed, so I know that it has to be something in the dimmer (especially since when I walked in, everything was off) I can ask the electricians if I see them if they working with the dimmer system, but I kind of doubt that they were. And I'll look for warm up or preheat too...

Just so I know, also, is it possible that something can happen when we turn the dimmers back on (like them overheating if the fan hasn't been running or something)

[Van]

OK, I'll throw in two cents.
1. Check the DMX runs, or at least try to see where they run. Did the electricians that were installing the chandeliers, possibly run some power through a conduit that was carrying the DMX cable? It's possible that an induction current could cause enough interference to create a similar problem.
2. Being that it's all the fixtures, it sounds as if you could easily isolae this problem to the control module, in the dimmer rack. As was stated earlier, a complete shut down and reset of the control module may fix the issue. Again, as stated earlier there are often "reset" procededures to be followed.

Remind the electrical contractors that they are working around some extremely sensitive "high Tech" equipment and they can't simply turn things off willy nilly.

[JD]

Ah yes! EDI, I have seen this before.

The first thing to check (if all the lights are doing it) is the line voltage. If it is too high, this will throw off the ramp generators (they run 24/7 unless the power is cut off.) By high, look for 127 to 132 volts. EDI uses a parabolic dimmer curve, it doesn't take too much to really throw it.

The second thing that comes to mind (Especially if they are all in one pack) is the low end trim pot. If it gets noisy / dirty it can cause this to happen. If it has, the temporary solution sounds stupid, but here it is: Slap the dimmer pack with your fist! Usually, the vibration will be enough to quiet the trim pot down. If this works, you want to have it serviced of the problem will come back.