Why are my lights flickering?

[Amiers]

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.

 

[Stevens R. Miller]

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!

 

[derekleffew]

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:

...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.

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.

 

[microstar]

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.

 

[Stevens R. Miller]

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.

 

[microstar]

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.

 

[tyler.martin]

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.

 

[Stevens R. Miller]

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.

 

[Stevens R. Miller]

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:

 

[derekleffew]

...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/ .

 

[RonHebbard]

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.

 

[Stevens R. Miller]

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.

 

[Stevens R. Miller]

@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.

 

[JohnD]

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

 

[Stevens R. Miller]

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...

 

[derekleffew]

... 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.

 

[Stevens R. Miller]

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.

 

[RonHebbard]

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.

 

[STEVETERRY]

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

 

[Amiers]

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.