Lights randomly strobe and flash

[TimMc]

Whoo! hold the bus, you just expanded the nature of your problem to include your com system?
That's a biggie. sounds like a cabling problem, or some other large electrical item (HVAC?) starting up and superimposing a lot of noise on the system. Possible big-time ground loop issue.

You're on to something, JD. Party line coms like Clear Com, Telex or RTS are pretty darn robust; about the only thing to take them down is physical disconnection or loss of mains power. The OP also mentioned a loud noise backstage...

Here's one possibility (speculation warning) - Somewhere on the deck the com line and DMX are run together and are being pinched, crushed or otherwise physically abused by a prop, set piece, wagon caster, maybe a door.

Another possibility - that someone mistook a DMX line for a coms line and plugged it into a belt pack. A ClearCom call signal would do some pretty ugly things to a DMX input, I'd imagine. Perhaps less so with RTS/Telex as they use tone signaling for the call light instead of DC.

The seemingly simultaneous nature of the failures is interesting.

 

[RonHebbard]

Note that *most* UPSs are not continuous or line-interactive these days; they're switchover, which is a) half the price, and b) won't have any impact on the waveform until they trip.

We have an in-depth thread on this somewhere that someone oughtta pin.

I believe that was one of my threads and I'm still waiting to receive my Middle Atlantic Products UPS 2200R. My supplier inadvertently ordered their cheaper 'S' series model, which isn't line interactive, thinking he'd save me some money but I told him no, I rather have the model I ordered. Soon. Hopefully soon. Meanwhile, at 90 pounds, the couriers are getting richer.
Toodleoo!
Ron Hebbard.

 

[TNasty]

I was just sorta thinking th

Note that *most* UPSs are not continuous or line-interactive these days; they're switchover, which is a) half the price, and b) won't have any impact on the waveform until they trip.

We have an in-depth thread on this somewhere that someone oughtta pin.

I was just proposing that a continuous supply or a true sinewave UPS would be better, since it would prevent any strange noises *when* it trips. I'm pretty sure most units enter a "tripped" state when they boost or reduce voltage. My unit makes an audible "buzz" sound whenever it's doing its AVR stuff, and a solid relay latch sound when it toggles.

For anybody who isn't familiar with UPS units, AVR just stands for Automatic Voltage Regulation. Its function is to help maintain a normal voltage output by modifying the input power by either boosting or limiting its voltage.

You're on to something, JD. Party line coms like Clear Com, Telex or RTS are pretty darn robust; about the only thing to take them down is physical disconnection or loss of mains power. The OP also mentioned a loud noise backstage...

Here's one possibility (speculation warning) - Somewhere on the deck the com line and DMX are run together and are being pinched, crushed or otherwise physically abused by a prop, set piece, wagon caster, maybe a door.

Another possibility - that someone mistook a DMX line for a coms line and plugged it into a belt pack. A ClearCom call signal would do some pretty ugly things to a DMX input, I'd imagine. Perhaps less so with RTS/Telex as they use tone signaling for the call light instead of DC.

The seemingly simultaneous nature of the failures is interesting.

I wouldn't find it very likely that everything would even get started correctly if there was a device-line mismatch; everything would probably go crazy from the start.
But the pinching does sound possible, considering that most of the data lines are probably run through the same conduits.
Although, I wouldn't be surprised if there was a DMX fixture along the line somewhere that was acting up. Possibly a dying power supply could cause this interesting issue intermittently. I also know for a fact that my Telex system is a tad fussy (you can make some neat interference sounds just by touching the pins in the jack); perhaps a moment of strange power could cause the unit to enter a "zombie" mode, or even some funky interference that a cable picked up along the line.

 

[JD]

Regarding UPS/Line Filter/Conditioner. This would only work if the noise was entering the system through the AC mains. Even then, it would do noting to correct a ground loop as the ground conductor is simply passed through on all units.
When you are dealing with data corruption, a large source of that problem is through direct induction. Basically, a current traveling through one wire induces a voltage in another wire. No different than the primary and secondary of a transformer. Proximity is a factor. For example, a data cable that does not have to be run through conduit is cable tied to an existing conduit to keep the install neat. A large current surge, such as a motor starting, can produce a significant EMP. (Ever listen to a conduit when that happens? You can actually hear the wires jump.) Another way this "broadcast" can happen is when the waveform of the load in the source cable is distorted. (Dimmer or low-PF lamp) The squaring of the waveform allows for harmonics to be broadcasted all the way up into the AM band.

 

[RonHebbard]

Regarding UPS/Line Filter/Conditioner. This would only work if the noise was entering the system through the AC mains. Even then, it would do noting to correct a ground loop as the ground conductor is simply passed through on all units.
When you are dealing with data corruption, a large source of that problem is through direct induction. Basically, a current traveling through one wire induces a voltage in another wire. No different than the primary and secondary of a transformer. Proximity is a factor. For example, a data cable that does not have to be run through conduit is cable tied to an existing conduit to keep the install neat. A large current surge, such as a motor starting, can produce a significant EMP. (Ever listen to a conduit when that happens? You can actually hear the wires jump.) Another way this "broadcast" can happen is when the waveform of the load in the source cable is distorted. (Dimmer or low-PF lamp) The squaring of the waveform allows for harmonics to be broadcast all the way up into the AM band.

In the case of one installation that STILL annoys me, I installed a 2 channel Clear-Com system (One channel handled all production areas while the second channel handled only the FOH manager's lobby location next to the coat-check counter and entry doors into the performance space for co-ordination when admitting late-comers. Both channels were only available to the stage manager who had the powered main station. ) into a civic owned amateur space running it entirely in 1/2" and 3/4" EMT hammer-drilled on to concrete block walls. I took great pains to install all of the conduit neat and pretty with flawless bends and not running parallel to any existing power feeds in conduit or BX (I believe what I refer to as BX is more commonly referred to as "Metal Clad" by Americans.) Within months of my completing the installation totally to code, a non IBEW electrical contractor was brought in to install a single phase 120/208 volt (Two legs of a three phase system plus neutral and ground) 60 Amp sub-panel to power a cooking show renting the space for two months during the summer. You can probably see this coming; a run of nylon jacketed 3 conductor 6 gauge [+ ground] Ty-wrapped to 75' of my impeccably installed, and hum-free, comms pipe.
To say I was annoyed would be an understatement.
Toodleoo!
Ron Hebbard.

 

[JD]

I still call it BX! Sometime in the last 20 years somebody changed the name without telling me
(ok... maybe 40 years....)

 

[RonHebbard]

I still call it BX! Sometime in the last 20 years somebody changed the name without telling me
(ok... maybe 40 years....)

In 1999 I was the on-site person subcontracted to supervise all A/V and show control aspects of a two story installation for Madam Tussaud's in Las Vegas. The IBEW electrical foreman, Chris Anderson, informed me BXL was no longer manufactured for use below grade and that our flexible metal jacketed cables were known as "metal clad". I was there for four and a half months which was the legal limit of my stay as a sub-contractor to a Canadian company sub contracted to a US company hired directly by Tussaud's British parent company. Wet's outdoor dancing fountains and the giant animatronic beings at the Neptune show in Caesars were among the most impressive installations I recall. I was able to wangle a two hour visit below, above and behind the Neptune show and deemed it a good piece of work. The basement room devoted to the safe control of live gas flames I found particularly interesting.
Toodleoo!
Ron Hebbard.

 

[Van]

I still call it BX! Sometime in the last 20 years somebody changed the name without telling me
(ok... maybe 40 years....)

"Greenfield"is what we used to call it, when I was a knee-high to a grasshopper....

 

[Jay Ashworth]

Nah; Greenfield is different stuff.

BX and MC (it's new Code name) are the same thing -- and it was still called BX when I took Electricity in high school.

Greenfield is the stuff with a finer pitch, smoother surface, and waterproof plastic jacket of some type. Greenfield is *conduit* where BX is *cable*, coming preloaded with conductors.

Unless I'm nuts.

 

[RonHebbard]

"Greenfield" is what we used to call it, when I was a knee-high to a grasshopper....

Grasshoppers still tower over me but we called it Greenfield too back in the days when I was bending 4" ridgid with a Blackhawk segment bender. I fondly remember the day when the electrical contractor I was apprenticed to purchased a shiny new Greenlee one-shot bender AND an electrically operated pump to drive it. Prior to the one-shot, it used to take a well honed team of two of us a four hour morning to bend one 4" rigid ninety without it having any roll within it. With the original horizontal one-shot we were banging them out in less than an hour and having coffee break too. I completed my apprenticeship prior to the introduction of 'clock-style' benders but I was a wiz with both sizes of "Chicago's"
Greenfield was only sold empty and we cut it to length to suit then we pulled in wiring.
In Las Vegas, IBEW foreman Chris Anderson was ordering up whatever cables he wanted and receiving 'metal-clad' overnight for next-day installation. On our portion of the site a popular order contained 8 x 12 gauge stranded copper conductors identified as follows: Red, white with red. Black, white with black. Blue, white with blue. Green for normal grounds and green with yellow for isolated grounds. He was also able to order, and receive overnight, metal clad Belden 9841 and 9842 which we were running for our seven universes of DMX sourced from our seven Alcorn McBride SMPTE synchronized DMX 512 recorder / players.
I recall being amazed in Las Vegas when I realized the foreman on the Italian site with the interior and exterior moats didn't have anyone doing any manual bending. Pipe, both rigid and EMT, was ran straight or with factory manufactured bends or with lengths of stainless flex he called 'Flex-elles'. (Sp?) He didn't have as much as a 1/2" EMT bender on site.
Thanks for the memories @vanjmcqueen
Edit: Sorry, omitted a word.
Toodleoo!
Ron Hebbard.

 

[RonHebbard]

Nah; Greenfield is different stuff.

BX and MC (it's new Code name) are the same thing -- and it was still called BX when I took Electricity in high school.

Greenfield is the stuff with a finer pitch, smoother surface, and waterproof plastic jacket of some type. Greenfield is *conduit* where BX is *cable*, coming preloaded with conductors.

Unless I'm nuts.

Up here during my apprenticeship, we had Greenfield, (Which we ALWAYS received empty) flex and "Liquid-tight" which arrived with a continuous black nylon flexible outer jacket, occasionally grey, and the fittings threaded into / onto the ends and bushed the inner edges.
I'll politely bite my tongue and refrain from assessing your potential nuts-ness.
Toodleoo!
Ron Hebbard.

 

[RonHebbard]

Nah; Greenfield is different stuff.

BX and MC (it's new Code name) are the same thing -- and it was still called BX when I took Electricity in high school.

Greenfield is the stuff with a finer pitch, smoother surface, and waterproof plastic jacket of some type. Greenfield is *conduit* where BX is *cable*, coming preloaded with conductors.

Unless I'm nuts.

They had electricity when you were in high school???
I thought we were still wicking whale oil back then.
Toodleoo!
Ron Hebbard.