# Why are my lights flickering?



## Stevens R. Miller (Oct 31, 2017)

Well, yet another middle school is throwing curve balls at me. This one's system is based on a Lehigh DX2 with a rack control system (picture below) and a small architectural control processor with four faders (a master and three that each control a part of the house). The ACP has a Doug Fleenor Designs PRE10-A DMX512 10-Zone Wall Controller with ten presets and and an LED that indicates that it is passing DMX data through it (at which time it gives up control).

We plug our computer into the ACP (we're running QLC+ and using an Enttec OpenDMX), and things work as expected. But last night, we noticed one of the lights flickering. I thought it was arcing, but then we saw that others were doing it. As the evening wore on, it got worse, to the point where it looked like a disco did in my college days (late '70s). We thought maybe the computer was the problem, so we disconnected it. The ACP includes an "all on" preset, and a few others, including an "apron only" preset. When we activated "apron only," we again saw lights that should have been off flashing on and off. By "on and off," I mean a very brief "on" time, followed by anywhere from half a second to several seconds of "off" time. This is with no computer connected.

We cycled the power on the rack and the problem seemed to go away, but returned after a few minutes. Three of us were working on this and all agree that it seemed to follow the same progression each time we cycled the power: the problem went away, then returned after a few minutes, gradually growing worse. I will admit, however, that this observation is more anecdote than science. What is certain is that the problem always returned.

At the rack, each dimmer is in a module paired with another. Each has two green LEDs on it, labeled "A" and "B." We noticed that whenever a light flickered, its LEDs also flickered on its dimmer. We also noticed that, if all lights were off, there was no flicker. This was true when the computer was connected and streaming DMX data too: if even one light was up, others would flicker, but nothing flickered if we set the scene to total blackout.

We tried swapping dimmers that were flickering with others that weren't. The problem stayed with the slot the dimmer goes in, not with the dimmer. We concluded, therefore, that something upstream of the dimmer and downstream of the computer input, was sending sporadic signals of some kind. This would imply that most likely the culprit is either the ACP, or the rack module. We looked inside the rack to see if there was a DMX input downstream of the ACP, but what we found was not a five- or three-pin plug (there's actually just a terminal strip in there that the ACP apparently feeds into), so we couldn't connect downstream of the ACP.

Of course the school has put in a work order for service, but our show is supposed to open on Friday, so I am not optimistic that the contractor will visit before then, much less fix the problem. But we are stumped!

Any suggestions?


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## Amiers (Oct 31, 2017)

Flickering is generally a power issue or failing dimmer.

Take the fixture that is connected to that dimmer and run it to full. Wait 5-10 mins and start turning on other fixtures til it flickers that will tell you if its power. 

Failing dimmer you can turn on the problem dimmers and set them at 35-50 percent. If they flicker the dimmer isn't doing it's job properly.


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## JohnD (Oct 31, 2017)

Have you tried calling Lehigh support? Granted they aren't ETC so I wouldn't expect that level of service but worth a try.
http://www.lehighdim.com/lw2/supconts.php
(Not to be snarky, but I question the wisdom of using "lehighdim" for their website, not really very positive.)


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## microstar (Oct 31, 2017)

JohnD said:


> Have you tried calling Lehigh support? Granted they aren't ETC so I wouldn't expect that level of service but worth a try.
> http://www.lehighdim.com/lw2/supconts.php
> (Not to be snarky, but I question the wisdom of using "lehighdim" for their website, not really very positive.)



I've had nothing but positive experience talking with Lehigh tech support on the phone even dealing with a discontinued product. They may not be ETC, but they've been in the lighting control business for over 50 years so they must be doing something right. Just sayin'


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## Robert (Oct 31, 2017)

Air flow and heat build up can also cause cascading flickering. Check for obstructed air flow and bad fans. Knowing of the dimmer was going to full then off or from full to off could also indicate a bad dimmer module.


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## jhochb (Nov 1, 2017)

Good Morning Steve

Is this isolated to a few circuits?
If so, try swapping module to see if the issue moves. That will tell you if its the mod.


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## Mistermon (Nov 1, 2017)

I'm going to +1 Robert's post. Had that happen to me in a 70's ish auditorium with Colortran dimmers. Cleaned the air sensor and blew the dust out of the racks and problem was solved.


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## Stevens R. Miller (Nov 1, 2017)

Thanks for the ideas, fellows! The problem does not move with a dimmer, but stays in the slot. That is, if I see the flicker on a given dimmer, and pull that dimmer out, then swap a different one that wasn't flickering into its place in the rack, the different one I swap in starts to flicker. But the flicker isn't limited to any particular circuit. It comes and goes all over the system. It also doesn't depend on load. I can bring up a single instrument and others (that should stay completely dark) will begin to flicker.

Now, here's where it gets more confusing: the school put in a "work order" on this, which usually means nothing will happen for at least 30 days. But someone must have pushed a bit, as an electrician worked on it yesterday. This was a school system guy, not a tech from the outside contractor that does theater support. The school was supposed to call me so I could watch the guy and help demonstrate the problem, but they didn't. In fact, no one was with him at all when he worked on it, so no one knows what (if anything) he did. But the director found out he had been there and asked me to rush in during rehearsal last night and test the system. I was unable to reproduce the problem.

Of course, when you are dealing with a flickering light, you only know if the problem still exists (because you can see the light flickering). You don't really know if the problem has been solved, because a light that isn't flickering _right now_ might start to flicker again at some future time. As suggested above, maybe a good cleaning was all it needed and maybe their guy did that. But I can't tell, of course, because the rack is in a locked cabinet and getting them to open the cabinet for me is one of those things you only ask for just so many times before wearing out the good will you need to get them to do it.

So...

For the moment, it may be working. We have another rehearsal tonight, during which I will test it all again.

I should have mentioned this before, but yet another problem the rack has is that, after I shut down my computer and switch the ACP to "off," the cooling fan stops in the rack cabinet. Except that, after about ten minutes, it starts up again for a minute or so, then shuts down again. And it never stops doing this. About ten minutes off, then one minute on, over and over. I suppose it's possible that the rack (which is still on) builds up enough internal heat to trip a thermostat, which opens again after the fan has blown for awhile. If my other problem stays solved, I'll pretend that makes sense and ignore the fan issue.

As ever, the help I get here is much appreciated. (I hate working in the middle schools, but I love the help!)


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## microstar (Nov 1, 2017)

So did you call Lehigh tech support?


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## RonHebbard (Nov 1, 2017)

Stevens R. Miller said:


> Thanks for the ideas, fellows! The problem does not move with a dimmer, but stays in the slot. That is, if I see the flicker on a given dimmer, and pull that dimmer out, then swap a different one that wasn't flickering into its place in the rack, the different one I swap in starts to flicker. But the flicker isn't limited to any particular circuit. It comes and goes all over the system. It also doesn't depend on load. I can bring up a single instrument and others (that should stay completely dark) will begin to flicker.
> 
> Now, here's where it gets more confusing: the school put in a "work order" on this, which usually means nothing will happen for at least 30 days. But someone must have pushed a bit, as an electrician worked on it yesterday. This was a school system guy, not a tech from the outside contractor that does theater support. The school was supposed to call me so I could watch the guy and help demonstrate the problem, but they didn't. In fact, no one was with him at all when he worked on it, so no one knows what (if anything) he did. But the director found out he had been there and asked me to rush in during rehearsal last night and test the system. I was unable to reproduce the problem.
> 
> ...


@Stevens R. Miller Please tell us that the locked cabinet has adequate ventilation.` 
Toodleoo!
Ron Hebbard.


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## Stevens R. Miller (Nov 1, 2017)

microstar said:


> So did you call Lehigh tech support?


If I do that, I will be going around the school system electrician who is currently working on it. That's a proven way to make him mad, which I don't want to do. If he the problem comes back and he can't solve it, I may call them.


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## Stevens R. Miller (Nov 1, 2017)

RonHebbard said:


> @Stevens R. Miller Please tell us that the locked cabinet has adequate ventilation.`



I could do that, but I'd probably be lying to you. It does have vents in the back and there's a fair amount of space behind the dimmers and the back of the cabinet. The whole thing is _years_ old. If it were going to fail (or, God forbid, ignite) for lack of cooling, it would have done it a long time ago. I do wish they'd installed the whole thing in the hallway, not just off stage, though. It's obnoxious to have to listen to the fan blowing through a whole show.


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## RonHebbard (Nov 1, 2017)

Stevens R. Miller said:


> I could do that, but I'd probably be lying to you. It does have vents in the back and there's a fair amount of space behind the dimmers and the back of the cabinet. The whole thing is _years_ old. If it were going to fail (or, God forbid, ignite) for lack of cooling, it would have done it a long time ago. I do wish they'd installed the whole thing in the hallway, not just off stage, though. It's obnoxious to have to listen to the fan blowing through a whole show.


@Stevens R. Miller You're not alone. There is a Strand CD80-96 rack in a Catholic Basilica in Hamilton, Ontario, Canada. The rack was installed per specs from New York City designers as part of a total renovation after a fire demolished the entire interior of the church. There's the normal pipe organ at the rear of the church and a secondary set of pipes in an acoustically coupled niche high up the MSL wall. Someone decided the best place to locate the rack was jammed into this acoustically coupled niche where the fan noise was an immediate problem. Next step, the experts from NYC had the rack enclosed within a plywood "phone booth" with double walls and insulated with Roxul. Kept the noise in just fine. Kept the heat in too. One by one the dual-SCR blocks died. The experts from New York apparently prayed the rack would survive the warranty period. I haven't seen the rack in several years. The last time I saw the rack, it had slower fans installed and the "Easy Bake Oven" door was being left ajar. Let's see if I get in trouble for this post too.
Toodleoo!
Ron Hebbard.


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## Amiers (Nov 1, 2017)

Well I would say if you got the Electricans number to give him a friendly ring and ask him out for a cup of coffee or lunch to pick his brain about what he did. 

Make friends with the man and you won't need work orders for small stuff.


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## Stevens R. Miller (Nov 1, 2017)

RonHebbard said:


> ...the experts from NYC had the rack enclosed within a plywood "phone booth" with double walls and insulated with Roxul. Kept the noise in just fine. Kept the heat in too.


My ham radio neurons are all thinking "Danger Will Robinson!"
My lawyer neurons are all thinking "Gross negligence! Punitive damages!"


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## Stevens R. Miller (Nov 1, 2017)

Amiers said:


> Well I would say if you got the Electricans number to give him a friendly ring and ask him out for a cup of coffee or lunch to pick his brain about what he did.
> 
> Make friends with the man and you won't need work orders for small stuff.



Excellent advice. I'd follow it, too, if it weren't for the fact that I have just reached my limit when it comes to coping with middle school lighting systems. The company I am working with does one big show every summer in a high school. The high school has a drama teacher, which means most of its equipment is maintained quite well. Also, they have a catwalk and a scaffold, so we can replace any lights that burn out and/or redirect them, all without having to engage in any diplomacy.

Gonna turn 60 next year. I find the words, "I am too old for this sh_t" coming to mind more and more often, of late.


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## Amiers (Nov 1, 2017)

Just have to will it not to happen, Murtaugh.


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## RonHebbard (Nov 1, 2017)

Amiers said:


> Just have to will it not to happen, Murtaugh.


@Amiers Perhaps I've missed your point. To my limited knowledge, the alternative to aging is death. I'm still going with aging as the better alternative.
Toodleoo!
Ron Hebbard.


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## Amiers (Nov 1, 2017)




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## Stevens R. Miller (Nov 1, 2017)

https://m.facebook.com/story.php?story_fbid=10208291060552604&id=1786389382&_rdr

Problem is back. Here's a video of it.


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## Amiers (Nov 1, 2017)

Power issue or overheating. you can test the over heating by turning everything on and seeing what the rack does as far as fan speed and if you can recreate the problem. Would have a few cameras setup or people with phones. 

If it's power well that's gonna suck. Means there's potentially not enough power for the system anymore and fixtures will have to be stripped til the ghosting goes away or you upgrade your service. I doubt the latter is going to happen.


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## Stevens R. Miller (Nov 1, 2017)

Well, my CB friends, I am in deep doo-doo here. The problem came back with a vengeance, with the lights sometimes making me think John Travolta was about to take the stage. There is no realistic hope that the outside vendor will be called in time to open our show two Fridays from today, and we cannot use these lights. We have an old, eight-channel, analog dimmer we can bring in. We have an ADJ four-plug dimmer pack. We have six ADJ Ultra Hex Bar 6's we can hang. And I have a small ($300) budget to buy things with.

Looking at Amazon, I see lots of multicolor LED instruments that are in the $20-$30 range that claim powers in the 30-40 watt range. Do these really work? I would expect they are pretty crummy, but if they will get us through a show, I can overnight them and hang them on Monday. We already have loads of DMX/XLR cable to connect them together.

Any other ideas? Anyone in the vicinity of Herndon, Virginia that can lend me a few lights? Rent them? Donate them to a non-profit? Anything?

We're pretty desperate here. This is our first show in this school and no one was expecting something so catastrophic. Any and all help most gratefully accepted.

Thanks!


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## derekleffew (Nov 1, 2017)

Stevens R. Miller said:


> https://m.facebook.com/story.php?story_fbid=10208291060552604&id=1786389382&_rdr
> 
> Problem is back. Here's a video of it.


So is the flickering Fresnel supposed to be ON or OFF?

I'm going to disagree with most in that I don't think it's a temperature or power problem. [One exception: A loose neutral on the main feeding the dimmer rack can cause symptoms of flicker. It's relatively easy for a qualified electrician to check the torque of the lugs upstream.]

I say you were on the right track with:

Stevens R. Miller said:


> ...We concluded, therefore, that something upstream of the dimmer and downstream of the computer input, was sending sporadic signals of some kind. This would imply that most likely the culprit is either the ACP, or the rack module. We looked inside the rack to see if there was a DMX input downstream of the ACP, but what we found was not a five- or three-pin plug (there's actually just a terminal strip in there that the ACP apparently feeds into), so we couldn't connect downstream of the ACP.



You need to find someone* with a DMX-ter (or similar DMX sniffer) with Flicker-Finder feature. And you'll need to cut a short DMX cable in half to temporarily land the bare end to the terminal strip.
*Barbizon or 4WallDC I suspect. Unless a CB member can do it for free lunch/adult beverage.


Stevens R. Miller said:


> Well, my CB friends, I am in deep doo-doo here.
> We're pretty desperate here. This is our first show in this school and no one was expecting something so catastrophic. Any and all help most gratefully accepted.


Is there any flickering when your computer is NOT connected? Limiting yourself to ten Fleenor presets is better than bringing in external lighting. Ridiculously cheap LED lights ARE NOT worth it for this application.


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## microstar (Nov 2, 2017)

Given the symptoms, I'm placing my bet on one of the following in order of probability:
1) dead or dying RAM battery/corrupted rack software in the SCM
2) a capacitor gone bad in the SCM
3) ACP remote panel has lost communication with the rack
4) PRE10A has gone flakey.
#1 thru #3 will require contacting Lehigh tech support while you are standing in front of the rack.
#4 can be eliminated by pulling it out and disconnecting the plug-in connector (the DMX control line will still be intact).
From the Lehigh DX2 manual:
View attachment 15473


I would spend the $300 on getting a knowledgeable repair tech to fix the problem.


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## Stevens R. Miller (Nov 2, 2017)

derekleffew said:


> So is the flickering Fresnel supposed to be ON or OFF?



OFF.

> Is there any flickering when your computer is NOT connected?



Yes. The ACP alone exhibits the problem.


> Ridiculously cheap LED lights ARE NOT worth it for this application.



How bad are they? Remember, this is a community theater production in a middle school, not a pro or semi-pro show in an actual theater, and we are running out of time. Will cheap LED lamps throw light I can control via DMX? That's all we need.


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## microstar (Nov 2, 2017)

After sleeping on the problem, I am revising my diagnosis by moving #2 up to #1:
Look for bad capacitors in the SCM power supply. The tops are usually bulged up as in the photo. Your comment that whenever you turn off the rack and then power it back up, the flickering stops for a while and then begins again seals the deal as this was the exact symptom for the DMX to analog decoder in the picture. Hope this helps!



Also, please don't go the cheap LED route. As enticing as it sounds, it's a very slippery slope and you will just be throwing money away.


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## tyler.martin (Nov 2, 2017)

I'm going to side with the issue potentially lying with the PRE10 as well. I've seen the DMX negative come loose on the termination, which leads to wonky DMX.

Pull it off the wall and check the terminations. I'd also say spend the money on a Service Tech visit. Get it fixed, then get the school to pay.


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## Stevens R. Miller (Nov 3, 2017)

tyler.martin said:


> I'm going to side with the issue potentially lying with the PRE10 as well. I've seen the DMX negative come loose on the termination, which leads to wonky DMX.
> 
> Pull it off the wall and check the terminations. I'd also say spend the money on a Service Tech visit. Get it fixed, then get the school to pay.



A termination issue would explain a lot. We never see any flickering when all channels are set to zero, but setting even one channel to full eventually causes dimmers that should be off to blink their lights on at random. The kind of random assignment of level data to channels that improper termination has been known to cause would look just like that.

An assistant principal at the school has taken an interest and asked me to detail what we know about the problem so he can forward that to his support contractor. With the comments I've received here, my own experiences with it, a video of the problem as it was happening, and the fact that I work at home and can be at the school in 20 minutes to meet the technician if called, I like to think I've done my bit to help them get this solved.

But after this is over, the other lighting crew members and I have agreed that we are going to take up bungee jumping, sky diving, or some other relatively sedate activity. My cardiologist is telling me that middle school lighting systems are too much for my heart to stand anymore.


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## Stevens R. Miller (Nov 3, 2017)

Oh, on a side note that theater techies might find interesting, our back-up plan has been to hang some LED light bars from the pipes ourselves, and run them directly from a computer, completely circumventing the school's system. That's not enough light for the show, so we also dug up an old dimming system that we are using to run four ellipsoidals on trees out in the house. We've ordered some crummy Chinese LED area lights as well, but the bars and the trees actually did a pretty good job last night. For those who enjoy history, here is a picture of our old control console, right out of The Stone Age:




And here's how much light we've been able to get so far, with our bailing-wire-and-spit lighting system:


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## derekleffew (Nov 3, 2017)

Stevens R. Miller said:


> ...For those who enjoy history, here is a picture of our old control console, right out of The Stone Age:


Looks brand new; I thought it was a current product. But this (I found a new site!) http://www.usedprice.com/items/pro-sound/lightronics/pro-lighting-equipment/tl1640-345206.html says 1992-1997. Currently rents for $15/day or $30/week in Portland OR http://www.prosoundonline.com/product/lightronics-tl-1640/ .


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## RonHebbard (Nov 3, 2017)

Stevens R. Miller said:


> A termination issue would explain a lot. We never see any flickering when all channels are set to zero, but setting even one channel to full eventually causes dimmers that should be off to blink their lights on at random. The kind of random assignment of level data to channels that improper termination has been known to cause would look just like that.
> 
> An assistant principal at the school has taken an interest and asked me to detail what we know about the problem so he can forward that to his support contractor. With the comments I've received here, my own experiences with it, a video of the problem as it was happening, and the fact that I work at home and can be at the school in 20 minutes to meet the technician if called, I like to think I've done my bit to help them get this solved.
> 
> But after this is over, the other lighting crew members and I have agreed that we are going to take up bungee jumping, sky diving, or some other relatively sedate activity. My cardiologist is telling me that middle school lighting systems are too much for my heart to stand anymore.


@Stevens R. Miller @Stevens R. Miller I wish you'd have bought yourself a Goddard Mini DMX'ter rather than the Red Army lights.
Toodleoo!
Ron Hebbard.


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## Stevens R. Miller (Nov 3, 2017)

derekleffew said:


> Looks brand new; I thought it was a current product. But this (I found a new site!) http://www.usedprice.com/items/pro-sound/lightronics/pro-lighting-equipment/tl1640-345206.html says 1992-1997. Currently rents for $15/day or $30/week in Portland OR http://www.prosoundonline.com/product/lightronics-tl-1640/ .



Those rental rates are just for the console. To run eight lamps, you need two power-packs. They want another $20 for those. Each.

Shoot, you can buy one used for about $150. It's not even DMX, though, so you can't integrate it into an existing system.


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## Stevens R. Miller (Nov 3, 2017)

RonHebbard said:


> @Stevens R. Miller @Stevens R. Miller I wish you'd have bought yourself a Goddard Mini DMX'ter rather than the Red Army lights.



That looks like a diagnostic tool. I don't get paid enough to troubleshoot this thing for them at that fine a level. Heck, if the school electricians or its contractors saw me using a gizmo like that on their gear, they'd probably banish me.


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## JohnD (Nov 3, 2017)

Have you considered paying homage to the history of theatre arts and ask them if it is ok to line the front of the stage with candles, or even higher tech with Coleman lanterns. You could have your lighting crew hunkered down in front of the stage to handle dimming and even hold gels in front of the lanterns. Just remember that all you really need for THEATRE is the passion and a plank.

Snarkily yours
John


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## Stevens R. Miller (Nov 3, 2017)

JohnD said:


> Have you considered paying homage to the history of theatre arts and ask them if it is ok to line the front of the stage with candles, or even higher tech with Coleman lanterns.



We have discussed giving each audience member in the front row a Maglite and a list of cue numbers, so the stage manager can sit in the pit and whisper the calls...


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## derekleffew (Nov 3, 2017)

Stevens R. Miller said:


> ... Heck, if the school electricians or its contractors saw me using a gizmo like that on their gear, they'd probably banish me.


And that would be bad, how? (Based on your previous statements.)

I previously suggested a DMX-ter, but that only *proves* the problem. @microstar has provided a path to *solving* the problem.


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## Stevens R. Miller (Nov 3, 2017)

derekleffew said:


> And [being banished] would be bad, how? (Based on your previous statements.)


Well, I'd like to stay until the show closes. And I do expect they'll fix it, eventually. (Turns out I already volunteered to assist with another production there in February, without knowing it would be in the same school or that we'd have these problems. One must deliver on one's commitments.)


> I previously suggested a DMX-ter, but that only *proves* the problem. @microstar has provided a path to *solving* the problem.


Very useful stuff for me to know, if I have my own space someday.


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## RonHebbard (Nov 3, 2017)

Stevens R. Miller said:


> We have discussed giving each audience member in the front row a Maglite and a list of cue numbers, so the stage manager can sit in the pit and whisper the calls...


 @Stevens R. Miller There you go, lighting solved and intercom too!
Toodleoo!
Ron Hebbard.


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## STEVETERRY (Nov 3, 2017)

derekleffew said:


> I previously suggested a DMX-ter, but that only *proves* the problem. @microstar has provided a path to *solving* the problem.


This is all great stuff, but no matter how smart the collective is, we lack enough data to make a definitive diagnosis.

1. Unlikely to be a DMX console issue, since local control from the rack processor creates the same flickering. I think a DMXter would be a waste of money, as much as I would like to send business to Bob Goddard!
2. Could be a control module failure (capacitors or other issues).
3. Video looks like a loss-of-sync problem which could be either a bad neutral connection (with associated zero-crossing issues) or a rack processor failure.

I suggest getting an expert on site to thoroughly diagnose. 

Where are you in the US? We might be able to identify a local resource that could arrive at the definitive answer.

ST


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## Amiers (Nov 4, 2017)

ST to the rescue. He's west of D.C. But he said he can't call in anyone. So we're kind of at dead lock.


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## Stevens R. Miller (Nov 4, 2017)

Well, _someone_ appears to have worked on it today. At the request of an assistant principal, I sent him a detailed description of what I know, emphasizing that the PRE10A could be the culprit. When I got there Friday night, the PRE10A no longer did anything, having apparently been disconnected from the rest of the system. I observed no flickering throughout a three-hour rehearsal. We've gone long periods with no flickering before, but never three whole hours. I don't know who did what, but it does appear that the PRE10A is no longer part of the system or, at least, that it is no longer powered.

I have read repeatedly that improper termination causes lights to go wacky, mostly because DMX receivers get confused about which levels are assigned to which channels due to reflections. Since we never see the problem when all levels on all channels are at zero, but do see it when even one channel is at full, I can easily believe that we have a termination problem. If removing the PRE10A solves that, I can live without the device.

Here, by the way, is a picture of what it looks like to use a mix of DMX and Stone Age lighting gear, when you have to cobble up an independent lighting system after the school's system fails you:




That's my lighting team-leader, MC, at the command desk. She's more artist than engineer but, in case she sees this, I'd like to say she has been as much of a trouper as anyone ever could be in dealing with this nonsense, and she "plays" those boards you see in the picture like a virtuosa (when I can get them to work ).


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## Les (Nov 4, 2017)

I love that you call it 'stone age' when it's not too far off from their current offerings! Really hard to beat those two-scene presets for simple control of a few dimmers.


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## microstar (Nov 4, 2017)

Stevens, you might tell your new friend, the assistant principal, that he should consider sending the PRE10A back to Fleenor for testing/repair as they usually charge only $30 plus return shipping to fix their out of warranty products. Of course it could be faulty installation too.


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## Stevens R. Miller (Nov 4, 2017)

Les said:


> I love that you call it 'stone age' when it's not too far off from their current offerings! Really hard to beat those two-scene presets for simple control of a few dimmers.


Yeah, "Stone Age" might be a little harsh. It certainly is more sophisticated than the stuff we had in my college days, which looked something like the picture below. It's just not what we expected to use and lacks the friendly graphical interface our software console provides. It also suffers by comparison when sitting next to the computer on that desk. If it were all we had, we'd actually be in pretty good shape. One adapts to the resources one has, after all.

My crummy Chinese lights just showed up. I'll give them a spin and report back here.


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## Stevens R. Miller (Nov 4, 2017)

microstar said:


> Stevens, you might tell your new friend, the assistant principal, that he should consider sending the PRE10A back to Fleenor for testing/repair as they usually charge only $30 plus return shipping to fix their out of warranty products. Of course it could be faulty installation too.


It's puzzling that it is still in the cabinet, just left unpowered. I mean, if I were the person who disconnected it, I'd have taken it out entirely for just your reasons. Perhaps the idea is that we're supposed to tell them if the problem went away and, if not, they'll just assume the PRE10A is a good one and, eventually, reconnect it.

And here is yet another example of how frustrating this all is for me: Someone made a significant change to the system, yet no one in my company has heard anything about it. None of us "lighting people" (as our director calls us) did it. No one has told any of us who did it. The assistant principal hasn't contacted me, even though I wrote him a detailed problem report yesterday morning (before, I assume, anyone came to work on it). I'm guessing the contractor showed up, told someone in the front office, "I'm here to work on the auditorium lights," and staff just let them in. Maybe an hour later, with the PRE10A disconnected, that person went back to the front office and said something like, "Okay, I made a change. Have them let me know if that fixes it, okay?" Staff probably said, "okay," and forgot that he was ever there, with the assistant principal never knowing anyone did anything.

I'll send him an e-mail and ask, but I had given him my phone number and he had said the school would call me when and if a tech came. I work at home and can be there in 20 minutes.

Art is about suffering, I guess.


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## TimMc (Nov 4, 2017)

RonHebbard said:


> @Amiers Perhaps I've missed your point. To my limited knowledge, the alternative to aging is death. I'm still going with aging as the better alternative.
> Toodleoo!
> Ron Hebbard.



A few years ago I had an appointment with my doctor to discuss some aches, pains and other body-mechanic stuff. After listening to my complaints I asked her what the proper course would be. She looked at me and said "I could order a bunch of expensive tests your insurance won't cover, they'll come back negative because there's nothing wrong with you. It's just that you're not 19 any more."

The closer to 65 I get the more I'm saying "I'm too old for this crap, where's the FNG?"

Edit ps: I see the forum software has automatic word-nanny replacements...


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## BillConnerFASTC (Nov 4, 2017)

You want stone age? This is a little closer:



My high school where I started working backstage in 6th grade - maybe because of light board - wasn't so old - more like:


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## JohnD (Nov 4, 2017)

TimMc said:


> A few years ago I had an appointment with my doctor to discuss some aches, pains and other body-mechanic stuff. After listening to my complaints I asked her what the proper course would be. She looked at me and said "I could order a bunch of expensive tests your insurance won't cover, they'll come back negative because there's nothing wrong with you. It's just that you're not 19 any more."
> 
> The closer to 65 I get the more I'm saying "I'm too old for this crap, where's the FNG?"
> 
> Edit ps: I see the forum software has automatic word-nanny replacements...


Last century when I had my coronary adventure I asked my primary doctor about coffee, caf or decaf. His answer was, "I'm not going to say one or the other, as soon as I do another study comes out disproving the last study." He did suggest perhaps start the day with caf and midday switch to decaf. I also asked him about being on a low sodium diet, I wanted to know that since sodium was so bad for people HOW COME they had a bag of salt water piped directly into my veins!!! He tried not to smile while telling me the body needs some salt. They also started me on IV rat poison for a blood thinner, then they switched me to a different blood thinner which was shots with those teeny needles into the tummy area.


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## JohnD (Nov 4, 2017)

BillConnerFASTC said:


> You want stone age? This is a little closer:


Not to be difficult but wouldn't stone age more likely refer to the stoneware crocks for salt water dimmers?


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## BillConnerFASTC (Nov 4, 2017)

JohnD said:


> Not to be difficult but wouldn't stone age more likely refer to the stoneware crocks for salt water dimmers?


That was why I said closer. I think handling the fire building chores at a camp fire is probably as close to stone age lighting control I can actually think of, Grunt telling story of the days hunt for the woolly mammoth or whatever. And were still telling stories.

Try one of the new blood thinners - really expensive rat poisoning. Been there done those including the heparin in the gut after being told I should not have survived the PE. I've come to the conclusion that coffee is fine, don't worry about salt - but I never add salt anyways - but do avoid sugar. All things in moderation (well - one activity I'll get all I can of.)


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## Stevens R. Miller (Nov 4, 2017)

TimMc said:


> The closer to 65 I get the more I'm saying "I'm too old for this crap, where's the FNG?"
> 
> Edit ps: I see the forum software has automatic word-nanny replacements...



I ran into that too! In my humble opinion, there should be an exception for the phrase, "I'm too old for this sh_t," but I can see the host's reasoning in filtering it.


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## microstar (Nov 4, 2017)

Stevens R. Miller said:


> It's puzzling that it is still in the cabinet, just left unpowered. I mean, if I were the person who disconnected it, I'd have taken it out entirely for just your reasons. Perhaps the idea is that we're supposed to tell them if the problem went away and, if not, they'll just assume the PRE10A is a good one and, eventually, reconnect it.
> 
> And here is yet another example of how frustrating this all is for me: Someone made a significant change to the system, yet no one in my company has heard anything about it. None of us "lighting people" (as our director calls us) did it. No one has told any of us who did it. The assistant principal hasn't contacted me, even though I wrote him a detailed problem report yesterday morning (before, I assume, anyone came to work on it). I'm guessing the contractor showed up, told someone in the front office, "I'm here to work on the auditorium lights," and staff just let them in. Maybe an hour later, with the PRE10A disconnected, that person went back to the front office and said something like, "Okay, I made a change. Have them let me know if that fixes it, okay?" Staff probably said, "okay," and forgot that he was ever there, with the assistant principal never knowing anyone did anything.
> 
> ...



I understand perfectly, it happens all the time when servicing school stuff. The left hand doesn't know what the right hand is doing most of the time! Just hopeful unplugging the PRE10A was the solution to the problem.


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## Stevens R. Miller (Nov 4, 2017)

My six new Crummy Chinese Lights have arrived. Got one out and up on the bench. Early impression is actually pretty good. It's bright enough to be useful, pulls 0.46A at 56W (according to my Kill A Watt meter), and its fan is whisper-quiet. Reacts correctly to my DMX instructions. Uses eight addresses, with no option I can find to change to anything less consumptive. That's kind of disappointing since I only need four of those eight (the first four control mode, color, speed, and master dimming, where "mode" means something like "strobe," "fade," "sound activated," "DMX," etc.). The last four are Red, Green, Blue, and White, which are all I really need. Still, one could put 64 of these into one universe. That's more lights than I've ever had to work with, so I'm not complaining.

Now, having just uncrated them, I can't say anything yet about reliability, nor much about durability. On the latter, they're clearly not going to take harsh treatment well. But they're reasonably solid, with a plastic enclosure about 1.4mm thick and two metal brackets with knobbed bolts. The brackets appear actually to be slightly different sizes, so one can fit just inside the other, which is good if you need to hang the instrument from a pipe (can use both brackets for a really rigid yoke). As predicted, the dimming curve is rather logarithmic, but I can live with that. The beam is a bit more spotty than I had expected. I anticipated a wider angle.

Oh, say, here's a question for you professionals: when the lamp casts a spot with a soft edge, how do you measure the angle? Just eyeballing it, I estimate the "working" part of the spot is about 30 inches in diameter, when cast from five feet away. 15 inches over 60 inches is 0.25, the acrtangent of which is about 14 degrees, so I am thinking this casts about a 28-degree cone. Is that anything like how it's supposed to be measured?


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## BillConnerFASTC (Nov 4, 2017)

Beam angle to 50% from center, field angle is to 10%.


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## Les (Nov 4, 2017)

Stevens R. Miller said:


> The brackets appear actually to be slightly different sizes, so one can fit just inside the other, which is good if you need to hang the instrument from a pipe (can use both brackets for a really rigid yoke).



That has been a trend with LED fixtures. It's known as a "kickstand" by some, and allows you to set the unit on the floor without needing to bolt it to a base.


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## RonHebbard (Nov 4, 2017)

Stevens R. Miller said:


> _Art is about suffering, I guess._


 @Stevens R. Miller Art is not about suffering. Art *IS* suffering.
Toodleoo!
Ron Hebbard.


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## RonHebbard (Nov 4, 2017)

Stevens R. Miller said:


> I ran into that too! In my humble opinion, there should be an exception for the phrase, "I'm too old for this sh_t," but I can see the host's reasoning in filtering it.


@Stevens R. Miller @TimMc You can probably get away with "I'm too old for this excrement!" and / or "Equine excrement" in lieu of BS. And then there're always my old standbys "Phuque!" and "Phucough!" Poor SpellCheck doesn't have a clue.
Toodleoo!
Ron Hebbard.


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## Stevens R. Miller (Nov 4, 2017)

Les said:


> That has been a trend with LED fixtures. It's known as a "kickstand" by some, and allows you to set the unit on the floor without needing to bolt it to a base.


It works pretty well. As I uncrated the other five and assembled them, I noticed that not only does one fit well inside the other, that "insider" is also a bit wider than the "outsider." Makes it easy to tell which is which, though I can't think of any other advantage to it.

One of them does have a slightly flaky XLR3 on its output side. That may be my cable, though. If it's the lamp, I will open it up and see if I can correct the problem. The shells aren't sealed. Appear to be serviceable with an ordinary Phillips.

Here are some pix on my bench:




They do produce the saturated colors that I have noticed are characteristic of LEDs.




Kill A Watt confirms they pull about 2.8A total, at 343W, when full up.




That last pic accurately shows that they are bit on the magenta side when you would want them to be as white as possible. Will have to correct for that in the color mix.


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## Stevens R. Miller (Nov 4, 2017)

RonHebbard said:


> @Stevens R. Miller Art is not about suffering. Art *IS* suffering.
> Toodleoo!
> Ron Hebbard.


_Now_ he tells me...


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## RonHebbard (Nov 4, 2017)

JohnD said:


> Not to be difficult but wouldn't stone age more likely refer to the stoneware crocks for salt water dimmers?


@JohnD Imagine, three scene preset, salt-water dimmers; Now imagine trimming them. 
Toodeoo!
Ron Hebbard.


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## microstar (Nov 4, 2017)

If you tape some plain ol' wax paper in front of them, it will even out the hot spots and diffuse the beam a little.


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## Stevens R. Miller (Nov 4, 2017)

microstar said:


> If you tape some plain ol' wax paper in front of them, it will even out the hot spots and diffuse the beam a little.


That sounds like a promising idea. I'll try it. Anything else that would widen the beam with less loss of light? Some sort of plastic negative fresnel lens maybe?


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## BillConnerFASTC (Nov 4, 2017)

I would assume the selador lenses that ETC supplies for a number of fixtures would do that.


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## Crisp image (Nov 4, 2017)

RonHebbard said:


> @Stevens R. Miller @TimMc You can probably get away with "I'm too old for this excrement!" and / or "Equine excrement" in lieu of BS. And then there're always my old standbys "Phuque!" and "Phucough!" Poor SpellCheck doesn't have a clue.
> Toodleoo!
> Ron Hebbard.


@RonHebbard Wouldn't that be bovine not equine? Although equine works just as well.


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## microstar (Nov 4, 2017)

Stevens R. Miller said:


> That sounds like a promising idea. I'll try it. Anything else that would widen the beam with less loss of light? Some sort of plastic negative fresnel lens maybe?



You really want Light Shaping Filter from Elation:
http://www.elationlighting.com/lsf-filters

Pricey at $100 per 20" x 24" sheet but it does work. You don't get near the beam spread they are advertising, but still very useful and doesn't cut the brightness as much as other solutions.


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## RonHebbard (Nov 4, 2017)

Crisp image said:


> @RonHebbard Wouldn't that be bovine not equine? Although equine works just as well.


*@Crisp image* You Sir are most definitely correct. You've got your horse excrement and then you've got your bull excrement. Most days we've no shortage of either. Horses for courses and bulls for balls. Select your flavor but PLEASE do so with decorum and finesse.
Toodleoo!
Ron Hebbard.


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## JohnD (Nov 4, 2017)

RonHebbard said:


> *@Crisp image* PLEASE do so with decorum and finesse.
> Toodleoo!
> Ron Hebbard.


Panache Ron, you forgot Panache, and I don't mean in the historical "stick a plume of feathers in it" sense.


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## EdSavoie (Nov 5, 2017)

DMX data too: 0"
class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch">

DMX data too?id=0"
class="bbCodeBlock-sourceJump"
rel="nofollow"
data-xf-click="attribution"
data-content-selector="#there was no flicker. This was true when the computer was connected and streaming DMX data too-0">...it looked like a disco did in my college days (late '70s)....We noticed that whenever a light flickered said:


> I could do that, but I'd probably be lying to you. It does have vents in the back and there's a fair amount of space behind the dimmers and the back of the cabinet. The whole thing is _years_ old. If it were going to fail (or, God forbid, ignite) for lack of cooling, it would have done it a long time ago. I do wish they'd installed the whole thing in the hallway, not just off stage, though. It's obnoxious to have to listen to the fan blowing through a whole show.



Before I comment on what I think might be happening, fan noise on the dimmer reminds me of our CD80 rack, where the dying fans have yet to be replaced (Our work order system has a nasty habit of taking forever with theatre related issues) the squeaking noise is very audible from it's position in the electrical room stage right of the house, really obnoxious when the room falls silent.

Anyways... With what you've mentioned as for symptoms, i'm wondering if the problem is indeed something to do with the processor or the control bus going to the dimmer modules. I'm reminded of a few different things. First off, I've seen older [autolink]processor[/autolink] based electronics go wonky as described after warming up. (Speaking in terms of both time turned on and heat) It also reminds me of my experiments controlling intelligent [autolink]LED[/autolink] strips, I noticed the control signal getting "sloppy" and falsely triggering LEDs other than the one specified, with random colours. This only happened when active data was being sent, as in lights turned on. I could limit the [autolink]effect[/autolink] by reseating connections, and making sure there was as little resistance as possible between (digital) grounds.

Even if heat isn't enough to make something die outright or spectacularly, it can most certainly slowly bake systems to death. I've seen (mostly computers) bake themselves in such a way where they would crash or become unstable only after having been on for some time.

This is of course all speculation. Someone with much, much more experience than I could probably comment moire accurately...

EDIT: Blast my 1:22 AM Control booth posting, I somehow missed two full pages of much more informative posts...


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## EdSavoie (Nov 5, 2017)

Stevens R. Miller said:


> They do produce the saturated colors that I have noticed are characteristic of LEDs.



Call me a new-age millennial if you must, but I absolutely *adore* the look of saturated blues.

In reference to kickstands, silhouetting from the front with very saturated hues by using them as footlights, while having lights up top washing the stage in a contrasting colour makes for a really nice effect.

It's even more fun when you accomplish the same with a small army of BLB tubes, our "Addams Family" production did a complete number ("The moon and me" for anyone following from home) almost exclusively front lit by clothing fluorescing

(Sorry attached image is of poor quality, it's from a very last minute and not really calibrated camera that was used at the time.)


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## RonHebbard (Nov 5, 2017)

EdSavoie said:


> [QUOTE="...it looked like a disco did in my college days (late '70s).
> 
> ...We noticed that whenever a light flickered, its LEDs also flickered on its dimmer. We also noticed that, if all lights were off, there was no flicker. This was true when the computer was connected and streaming DMX data too: if even one light was up, others would flicker
> 
> ...The problem stayed with the slot the dimmer goes in, not with the dimmer. We concluded, therefore, that something upstream of the dimmer and downstream of the computer input





Before I comment on what I think might be happening, fan noise on the dimmer reminds me of our CD80 rack, where the dying fans have yet to be replaced (Our work order system has a nasty habit of taking forever with theatre related issues) the squeaking noise is very audible from it's position in the electrical room stage right of the house, really obnoxious when the room falls silent.

Anyways... With what you've mentioned as for symptoms, i'm wondering if the problem is indeed something to do with the processor or the control bus going to the dimmer modules. I'm reminded of a few different things. First off, I've seen older processor based electronics go wonky as described after warming up. (Speaking in terms of both time turned on and heat) It also reminds me of my experiments controlling intelligent LED strips, I noticed the control signal getting "sloppy" and falsely triggering LEDs other than the one specified, with random colours. This only happened when active data was being sent, as in lights turned on. I could limit the effect by reseating connections, and making sure there was as little resistance as possible between (digital) grounds.

Even if heat isn't enough to make something die outright or spectacularly, it can most certainly slowly bake systems to death. I've seen (mostly computers) bake themselves in such a way where they would crash or become unstable only after having been on for some time.

This is of course all speculation. Someone with much, much more experience than I could probably comment moire accurately...

EDIT: Blast my 1:22 AM Control booth posting, I somehow missed two full pages of much more informative posts...[/QUOTE]
@EdSavoie *LOVED IT!* I recognized your quote _"...it looked like a disco did in my college days (late '70s)"_ the moment I read it whereupon I just HAD to read back to find the post you'd quoted from. Count on my young countryman to tag this meandering four page thread ALL THE WAY back to the OP's original post. Trust me on this @EdSavoie , you belong here. You fit in just fine even if you spell colour with a 'U'. Odd, our American buddies spell four with a 'U' and think nothing of it.
Thanks for visiting Master Ed and doing your best to drag us all back on course. ['Course' There's another of those words with 'U's we share in common.]
Don't forget to set your clocks back in about 11 minutes. [ Where are the instructions for my sand filled hour glass?]
*EDIT:* Clearly the blind old geezer's botched his quotes again.
Toodleoo!
Ron Hebbard.


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## EdSavoie (Nov 5, 2017)

I'm not blind yet I still managed to botch the quote...


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## RonHebbard (Nov 5, 2017)

EdSavoie said:


> I'm not blind yet I still managed to botch the quote...


 @EdSavoie *See!* I told you you fit in here and you're already an over-achiever at 18.
Toodleoo!
Ron Hebbard.


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## Jim allen (Nov 8, 2017)

Stevens R. Miller said:


> Well, yet another middle school is throwing curve balls at me. This one's system is based on a Lehigh DX2 with a rack control system (picture below) and a small architectural control processor with four faders (a master and three that each control a part of the house). The ACP has a Doug Fleenor Designs PRE10-A DMX512 10-Zone Wall Controller with ten presets and and an LED that indicates that it is passing DMX data through it (at which time it gives up control).
> 
> We plug our computer into the ACP (we're running QLC+ and using an Enttec OpenDMX), and things work as expected. But last night, we noticed one of the lights flickering. I thought it was arcing, but then we saw that others were doing it. As the evening wore on, it got worse, to the point where it looked like a disco did in my college days (late '70s). We thought maybe the computer was the problem, so we disconnected it. The ACP includes an "all on" preset, and a few others, including an "apron only" preset. When we activated "apron only," we again saw lights that should have been off flashing on and off. By "on and off," I mean a very brief "on" time, followed by anywhere from half a second to several seconds of "off" time. This is with no computer connected.
> 
> ...


I had the same problem with one of my ETC Sensor racks and it was the CEM module. Does your have one?? Don't know Leigh systems.


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## Stevens R. Miller (Nov 8, 2017)

Jim allen said:


> I had the same problem with one of my ETC Sensor racks and it was the CEM module. Does your have one?? Don't know Leigh systems.


What's a CEM module?


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## kenact (Nov 8, 2017)

Stevens R. Miller said:


> My crummy Chinese lights just showed up. I'll give them a spin and report back here.
> View attachment 15498



Just my own experience with "crummy Chinese lights".

I bought some cheap RGB/LED Par Cans. I've used them on a number of shows, but not without issues. When one of the instruments exhibited power problems at the plug, I discovered that the wire in the power cord was about as thin as the wire in my ear buds. I also discovered that, although they had a 3 wire plug, only 2 wires were connect.

Another issue I had with one instrument, green and blue were reversed.

In one production, my RGB/LEDs were extended from an older 12 channel, 2.4K dimmer pack, and just before our performance was due to begin, ALL the lights started flashing in what appeared to be a random order. I tried adding a terminator to the end of my DMX chain, to no affect. When I disconnected my RGB/LED chain, the flashing stopped. I found that one of my RGB/LEDs was causing the problem, removed it from the chain and ran the show.

I'm not too upset, because they were cheap, in the same price range as yours.


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## sk8rsdad (Nov 8, 2017)

Stevens R. Miller said:


> What's a CEM module?


It is the brain for a Sensor rack. It's basic function is to translate control protocols into firing signals for the dimmer modules.


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## derekleffew (Nov 8, 2017)

Stevens R. Miller said:


> What's a CEM module?


I don't know if that was rhetorical or sarcastic or other, but, from https://www.controlbooth.com/threads/cem.9026/ :

derekleffew said:


> *C*ontrol *E*lectronics *M*odule. A term for the ETC Sensor (and applied generically to other manufacturers') dimmer's "brain." The module on a dimmer pack or rack where various parameters are set. This will always include the pack's/rack's starting DMX512 address, and may include features such as voltage regulation, dimmer curves, implementation of secondary DMX or analog signals, etc. Prior to the Sensor's introduction in 1992, this item was often referred to as the "control card" or "control module."


I believe your Lehigh DX2 dimmer rack calls it the *S*ystem *C*ontrol *M*odule. (Gotta love those TLA s, right?)


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## carmellights (Nov 8, 2017)

EdSavoie said:


> DMX data too: 0"
> class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch">
> 
> DMX data too?id=0"
> ...


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## Stevens R. Miller (Nov 8, 2017)

derekleffew said:


> Stevens R. Miller said:
> 
> 
> > What's a CEM module?
> ...



It was other, where "other" is "ignorance." I really just didn't know.


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## Stevens R. Miller (Nov 8, 2017)

carmellights said:


> Before I comment on what I think might be happening...
> 
> (quite a detailed list of good ideas elided)
> 
> thoughts ?



Well, I dearly wish I had the time and unlimited access needed to pursue this as you and others have suggested. As an amateur techie in a community theater company that is only grudgingly tolerated in our public schools, I can only do so much.

The outside vendor that supports the school here is "Artistic Concepts Group." They sent a technician yesterday, fellow named Ryan, and I was lucky enough to be there when he arrived (where "lucky enough" was that I took my computer and camped out in the auditorim as soon as the school opened for election day). Ryan was unusually knowledgeable and also very patient. Alas, as is typical of comes-and-goes problems when the actual expert is on hand, the flickering did not recur, even after we reconnected the ACP. Ryan hung out for about an hour as we tried this and that, to no avail. During that time, he told me a number of interesting war stories regarding similar problems, many of which he said ended up being induced by unrelated equipment (like HVAC systems, and so on).

What this means to me is that I just can't fix this myself. If it comes back, I'll call ACG and ask them to send Ryan again and right away. Other than that, I think this one is just out of my league.


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