Super Trouper Flicker Problem.

ship

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Just finished service call to two Super Trouper’s c.1980's I think. Lights worked perfectly and no flicker noted, but was not looking for it. Back to the theater and one seemingly one is flickering. This flicker most detectable from the spot box position but also by way of designer in noting it.
They changed ballasts between fixtures, than lamps and even third a spare lamp between them. One still does it in all cases, the other also tested doesn’t flicker no matter what ballast or lamp. Absolute only fixture difference in service call, was we noted that one of the lamp housing assembly fans had a sort of like cardboard gate cover over the fan outlet blowing into the housing, the other didn’t have this housing to blow out of the way. We didn't fix that difference, only noted it in otherwise neither fixture had a difference of problem with running.

Initial thought, perhaps this cover has something to do with too much fan on the lamp or area? This now assuming it is the fixture lacking the cover. Don’t know yet which fixture they were having the problem with. Person that called me didn't have info onto which spot was having the problem.
If not the potential cause, having them check amperage at the fixture, voltage to the fixture and air conditioning vents nearer to the spot location. Don’t know what is causing the flicker to the lamp given both ballasts changed and three lamps tried. Only thing I know is one was missing a fan baffle, could that be the cause?
 
I would say that the most likely cause of excessive flicker in a Xenon followspot is the age of the lamp but that does not seem to be the case here. I am not aware of a cardboard-like fan baffle behind the fan housing output. There are safety switches that are activated by air pressure at that location. I believe an early design of these switches might have a small flag attached to the end of the arm but both spots should have the switches. I assume these are 2K? The 2Ks should have a magnet installed beneath the lamp that was claimed to be for arc stability. Is this a new problem? Do they know the hours on the lamps?

I once serviced a Super Trouper that the operators complained was getting too hot. Of course they still used it since it would strike. They just threw some towels on top. There was a bad connection at the terminal that clamps to the lamp. I don't know if it flickered but they used it until it finally failed.
 
If you have not seen it flicker in person, it may be time to ask them to define "flicker." (Especially since the lamp and ballast have been swapped.)
Is it a rhythmatic flicker, or just an occasional blink? If it's just an occasional blink it could be something as stupid as a bad connector ore receptacle.
Also, does this style use the anti-flicker magnet near the lamp? Can really run funky if that magnet got disturbed or flipped.
 
2Kw lamp and wow! Thanks for the above two posts, more to go with.

I was initially also thinking fan sensor switch with the (I remembered it as cardboard, but it could have been something else,) but the light strikes and we didn't notice any bypassing of the sensor. Were not looking for this but didn't notice it. Something to look at/for though. Both spots might not be the same age - one has a really old black switching ballast, the other a more modern ballast. Could explain why one has this fin, the other doesn't?

Magnets are both there and were inspected to be fine/proper. That's kind of a look at, is the magnet there, has it moved etc. type of inspection though. One can assume that the same lamps between two fixtures were tried and the older spare, they were installed correctly, and both lamps were inspected by me during the service call, both were used but in good condition. Hours are not known due to potential past switching between fixtures, but I think I replaced both last year.

Tension on the terminals I would assume not the case given how many lamps they tried, but possible if not the same operator installing lamps per both fixtures - something to check.

Interesting to define the flicker, how many IA can or are sufficiently trained in that detail - but great concept I also will have would never thought about asking in type of flickering but could provide all kinds of info on this and other flicker questions that come up. I can say that I inspected my tech's work in the shop and I did not see a flicker but wasn't looking for one or lingering to do so. My staff on the other hand, have spent some time bench focusing and optimizing them in the shop, he and they have a few years of experience under direct training, and I trust that he didn't note a flicker. Believe me, it will have been news he will have jumped at telling me about.

Interesting also, it's inside at a theater spot booth, perhaps in never seeing the flicker before noted by them, perhaps the older one or newer spot now got closer to the air conditioning vent, or perhaps they never noted it before this designer saw it. Would think they would if one can see the flicker better from the spot booth as told but who knows.

Gave them a few things to check, than didn't get a call back. I know they have a large rock show coming in I think tomorrow, I will give them a call and perhaps go up there given the new things to check and or questions to theorize about. Might have solved the problem already in adjusting the amperage as one of the checks I gave them. Don't know which spot was having the problem either, but can probably check the repair ticket to see if a large year difference between spots in serial number. This would tell me if one was older than the other and if perhaps the fan cooling sensor was bypassed. This will be a good thing to look at in the morning.

Thanks.
 
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You said the lamps were replaced last year! Duty cycle is about 2000 hours. I average just over 12 months before we need new lamps. Can't remember, do you need to rotate every 500 hours on those? You do on Lycians, and if you don't rotate it will cause this issue.

Cheers
 
1. I doubt the fixture was benched in the shop at the same downward angle it is operating at in the theatre. It's quite possible the unit didn't flicker in the shop but does in the field (or vice versa).

2. I'm guessing house staff is not rotating the lamps at the proper intervals, as @Lsly noted. I have to find my notes for the particulars, but one can either:
a) rotate the lamp 90° after every x hours (CW or CCW doesn't matter but always go the same way!),
or (and particularly to try to correct a flicker)
b) rotate the lamp 180°, boost the current 10A for 10 operating hours, then lower the current back down.

Some years ago, after a rather flicker-intensive fall season, I complained to both Lycian and Strong at LDI. They didn't like when I pointed out that every xenon lamp on the showfloor had some degree of flicker in it.

@JD, when I say flicker, I'm referring to an unstable arc, not unlike the effect of damp carbons. I realize, for today's technicians, I should find a more-relatable metaphor.
 
They aren't xenons, but a few years ago I was troubleshooting some flickering HMI arc Altman spots (575W/120V). I found either spot by itself was flicker free, but if both were on the same circuit, it was a flickery mess on the one with the older electronics. Is the problem spot always flickering, or only when both are struck? I have worked with xenon before, but they were part of an obsolete motion picture playback apparatus, and used brute force 3 phase rectifiers to make their DC.
 
Didn't get around to calling them today... internal modern mover lamp issues to work on. Very interesting observations above thanks including downward angle. I cannot speak to how the lamps were installed, but would assume in the same deionization wire up way normal. But also doubt past like 350 hours - but possible into the range of needing to rotate. Lamp hours is a thing I should be adding to my list of inspection things to do as another good idea for compiling. That and training the operators as a reminder to them, when they install them next, rotate as that is still the rule I believe no matter the brand at x hours.

Interesting in duty cycle 2,000 hours and blowing thru that in a year. Possible I suspect in if really busy but never seen that before at least on touring moving lights I'm aware of - don't really track our follow spot hours, and never really tracked full year use on movers in that way - see 2015 and note it's old normally in that amout of hours. But I inspected the followspot lamps, while there was a little bubble buildup on the anode (always forget cathode/anod but believe I remember arrow head), none on the other, and the globe was clear. Certainly lamps operating properly and with not more than a few hundred hours. This even if xenon where it's a little harder to judge the age by sizing the mushroom buildup with a HMI lamp.

One always flickering or only when combined with the other, another thing to look at. Thanks all, I learned a lot and have a punch list to look into, this assuming I have not heard more from them in either going with what they have or it solved. Further looking into this report is required and I will report back. Interesting.
 
Didn't get around to calling them today... internal modern mover lamp issues to work on. Very interesting observations above thanks including downward angle. I cannot speak to how the lamps were installed, but would assume in the same deionization wire up way normal. But also doubt past like 350 hours - but possible into the range of needing to rotate. Lamp hours is a thing I should be adding to my list of inspection things to do as another good idea for compiling. That and training the operators as a reminder to them, when they install them next, rotate as that is still the rule I believe no matter the brand at x hours.

Interesting in duty cycle 2,000 hours and blowing thru that in a year. Possible I suspect in if really busy but never seen that before at least on touring moving lights I'm aware of - don't really track our follow spot hours, and never really tracked full year use on movers in that way - see 2015 and note it's old normally in that amout of hours. But I inspected the followspot lamps, while there was a little bubble buildup on the anode (always forget cathode/anod but believe I remember arrow head), none on the other, and the globe was clear. Certainly lamps operating properly and with not more than a few hundred hours. This even if xenon where it's a little harder to judge the age by sizing the mushroom buildup with a HMI lamp.

One always flickering or only when combined with the other, another thing to look at. Thanks all, I learned a lot and have a punch list to look into, this assuming I have not heard more from them in either going with what they have or it solved. Further looking into this report is required and I will report back. Interesting.

Yeah, 2000 hours is just over 8 hours a day, 5 days a week every week for an entire year. Not an optimal operation cycle for any lamp. the 2k Xenon lamp with life of 2000hrs should be rotated 90 degrees every 500 hours. Never been a fan of the Xenon lamp (with the exception of it having a good spectral distribution). The 3k lamp is especially susceptible to flicker, for whatever reason. They are tempermental, unstable and everyone and their mother thinks they know how best to install and optimize them (I do not contend I am an expert). You will NEVER know any reality with a particular fixture unless you have had control of it from install to removal.
A lamp that is stable in a horizontal test position may or may not exhibit flickering in an operational tilt. Due to the nature of the DC powering the lamp, the Xenon lamp exhibits an off centered point source near the Anode (or Cathode), Mark D would be able to more effectively describe the lamp characteristics. the arc point deteriorates the post, hence the rotate requirement, and if the lamp had been overdriven and caused excessive pitting (or whatever the actual term is called) you could be seeing a flicker Regardless of lamp orientation.
And since you have changed lamps AND Ballasts, that leaves head cable and any circuitry in the lamp house, including improper cooling of the lamp.
Xenon...magnets...faceshields...plastic screws...
sigh.
 
Kind of preferred the old carbon arcs myself ;)
They didn't explode anywhere nears as often! I could leave the bomb-squad gear in the closet!
 
Today I exploded by dropping without warning three xeonon lamps inside a 10gal vented and sealed drum. Boy was there a jump from all about. Less from the exploding lamps, than from my drop drum.
 
Found out also today in a call to me instead of call to them, the fixture that was flickering failed to ignight on Tuesday for the show. Seems by Monday night in adjusting to 80 Amps, it was flickering less and the LD for the show was happy with that. The next day the lamp would not strike. Wish they will have not waited for three days before letting me know it didn't work out. Or did but the next day that solution prevented the lamp from striking. I just finished working on these lights and they were perfect, what't the problem now in solving.

Roa trip in the morning to Chicago in sending back this light to the shop to figure why it doesn't work. Ignightor perhaps.
 
Having some brain freeze here in remembering the layout (Has it been that long?) but I believe the ignitor, which has it's share of parts, is in the lamphouse and was not swapped. Unless this is a straight lamp/ballast failure, I think the ignitor would be that part I would be looking at. Let us all know!
 
The igniter design was changed from the original to something called a DC Igniter. It was much more reliable particularly when using a new ballast with an old spot. It is in the lamphouse. I haven't heard of either igniter causing flicker but maybe.
 
The igniter design was changed from the original to something called a DC Igniter. It was much more reliable particularly when using a new ballast with an old spot. It is in the lamphouse. I haven't heard of either igniter causing flicker but maybe.
I did have an HMI ignitor that was causing flicker and lamp dropout. Once replaced I autopsied the old unit (pain as it was potted) and found a bad crimp from the coil to the stud that went through the case. Basic thermal cooking problem. On those units, the ignitor was in series with the lamp.
 
Older ignitors have a card on top with a bunch of caps and resistors. New style is just a black box. Old ones didn't necessarily need the "drain wire," but new ones will not strike the lamp without it.

I doubt the ignitor is contributing to the flicker. Once the lamp is lit, it's pretty much out of the equation.
 
Older ignitors have a card on top with a bunch of caps and resistors. New style is just a black box. Old ones didn't necessarily need the "drain wire," but new ones will not strike the lamp without it.

I doubt the ignitor is contributing to the flicker. Once the lamp is lit, it's pretty much out of the equation.

I would agree with it being a long shot, and that it is passive during operation. But, it still has a high current series winding that is in the lamp circuit path. Once you eliminate the probable, you are only left with the improbable. Would sure help to see it first hand.

Still I would agree, when you hear hoof-beats, look for horses, not zebras.
 
Turns out the ME didn’t get full info from the spot op’s.
They did change ballasts between fixtures, but didn’t swap for the known to be working third lamp. Instead they relied on the spare lamp which was grey and had a lot of bubbling on both electrodes. Strike wire on the primary lamp was cut from anode as often normal practice, but wasn’t tied tight - it was loose. Spare lamp probably would not work.

Sails on the micro switch to the fans were not on either unit as observed on one during service call, but the micro switches were trippy enough that they were fine. Don't know what happened to the sail - I do remember it there - possibly even masking tape sail. Magnet was in place, all wiring was good and tight. All switches had a click. My theory is the lamp with the loose deionization wire was too loose as otherwise the lamp looked perfectly fine. I will tie a new wire on it for further testing before a new spare lamp is bought. Spare lamp I brought back to dispose of properly. New lamp I took with, struck right up and we adjusted the amperage back down.

IA house, will have thought the IA would do more followspot training of its people. I did some while there. Try not to touch the dichroic part of the heat shield! Someone advised the spot op’s to turn the amperage up to 100... when it wasn’t striking - bad idea. Another recommended reversing the magnet. Also specifically stated in the manual not to do. I left them with a copy of the manual to read - the same one I re-read the night before coming to work on the spot.

If the new lamp didn’t work, my next step was to swap ignitors between fixtures, and on from there between what was posted and the testing in the manual that gets complex. How do you discharge a capacitor anyway? I got lucky. Both ignitors were black box by the way.

Once done, I did get to go into the ceiling so as to confirm, yep there is eight or more c.1921 1Kw National X-Ray Reflector Company 12" Floodlight / X-Ray Projectors. And a bunch of “Strand Electric” Patt 123. With any luck, next time a drop off of gear I will get one of each. Or all of them to make work again in exchange for one of each. Would have to negotiate that many lights to work on. Must have been an amazing effect they had, wonder if this theater is listed in the on-line catalogues for example of what they were selling. Interesting, both that these are far different than my 1911 example in being double walled and lacking gel frame, and they had a silvered steel Plano Convex reflector attached to the moving lamp socket. Never seen that before, must have been some form of reverse reflector so as to send light out of the filament back to the reflector instead of directly out of the spot projector - unlike mine. They by 1921 were more like a beam projector than a flood light. Only imagine, this is pre-1928 and the Alzark aluminum reflector process, can’t just put a 1Kw lamp in front of a glass mirror reflector as is the case with these. But that’s what the rear non-moving reflector is - glass reflector. Technology back than used on say followspots today in National X-Ray invented a high heat mirror, and advertising for the brand says amazing effect.. Glad they still exist - enough fixtures, One could re-recreate the effect and perhaps once restored lights use them again on a show.
 
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So, the "lamp swap" wasn't really a lamp swap!
Once again, the hoof-beats were horses!
 

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