Strong 575 Followspot Burning Gels Please Help!

This screams bench focusing issue to me.
Agreed!

Light comes from all parts of the reflector and converges, therefore closing the iris limits the amount of light that gets to converge. Most of those look like thicker, low-temp gels. High temp gels feel more like cellophane. Still, the beam should not be converging in the color boom. Using the holes as a reference point, it looks like you have two locations that are hot-spots (as seen on the deep red and deep blue gels.) Something is out of whack with the lamp/reflector.
 
I don`t believe its completely a bench focus issue anymore, as I check the bench focus and messed around with it a bit, and dispite my best efforts, even when I have it bright and fairly even across the spot there is still a noticeable hot spot.
The hot spot I can move with the adjustments, although I just cant seem to loose it, or even minimize it without losing the consistent field or brightness.
I am not wondering as you said the problem is more under the cowling, either with the reflector, the bulb setting, or something else.
When I get another chance I will have to pull it apart and take a look at it.
To be honest I don`t know if it was ever benched focused properly, just enough to dim it down to prevent it from burning gels, or it was an old enough bulb as it had gels in it including the cinemoid, without a heat shield and didn`t burn gels in it before.
Thanks again,
soundguy99
 
I don`t believe its completely a bench focus issue anymore, as I check the bench focus and messed around with it a bit, and dispite my best efforts, even when I have it bright and fairly even across the spot there is still a noticeable hot spot.
The hot spot I can move with the adjustments, although I just cant seem to loose it, or even minimize it without losing the consistent field or brightness.
I am not wondering as you said the problem is more under the cowling, either with the reflector, the bulb setting, or something else.
When I get another chance I will have to pull it apart and take a look at it.
To be honest I don`t know if it was ever benched focused properly, just enough to dim it down to prevent it from burning gels, or it was an old enough bulb as it had gels in it including the cinemoid, without a heat shield and didn`t burn gels in it before.
Thanks again,
soundguy99
Bench focus is a lot more than evenness of field, it is about setting the convergence points in the optical train. Yes, in a simple bench focus you are trying to remove hot spots in the beam as seen on the object you are pointing it at, but when problems exist, you have to dig a bit further. It is very possible to have a perfectly even field and still have the unit way out of whack. This often has to do with the distance between the reflector and the iris. Hot spots have more to do with the placement of the arc center in the reflector. Spotlights (except beam projectors) have a point where all the light beams (or should I say vectors?) cross. If the cross too far back or too far forward, the efficiency of the spot decreases. In addition, things get very hot at the wrong places. It is very hard to find this cross point in the spec sheets, and I have often resorted to taking the hood off a know good spot, putting on welding glasses, and taking a dull finished piece of metal and looking for where it should be. I DO NOT RECOMMEND THIS as there are many safety issues. Still, the point I am making is that "bench focus" sometimes involves a lot more than getting the field even. In the case of this spot, at one time one of the spots did not have this problem. Since this has changed, we can assume something changed.
 
You have one good spot and one bad one. It's time to play "one of these things is not like the other." I would put them side by side, in a well lit shop, and carefully examine and compare the internal components. For anything in the optical train that is adjustable, measure its position down to the millimeter and set the bad one to match the good one. That will give you a new starting point for bench focus. It could be that too many variables are simply too far off adjustment to get it back to where it needs to be. You could find a lens or other part that isn't right, or is missing altogether, after someone made an emergency repair.

Just be sure to mark the bad spot with tape and a sharpy so you don't accidentally get them mixed up. You don't want two spots grossly out of adjustment.
 
Thanks for that JD,
It might resort to a service call from someone who actually repairs these things to calibrate it or at least take a look at them.
From what I have been told the 1 spot light always burnt gels as far as my manager can remember, the other one was find until we replaced the lamp. Neither spotlight had a Heat shield in them, so either an old lamp, bench focus or something else allowed it to operate without burning gels.
That without saying, if there hasen`t been a heat shield in there for quite some time, who knows how long these issues have been there, that no one has looked into. Over the years, they just found settings that worked, band aiding the problem so it worked or accepting that it doesn`t, without actually solving the real issue behind it.
With all this information, online, and help with forums like this one, with knowledgeable people like you, I just thought I would like to try and get to the bottom of this once and for all without, accepting, that "its the way it always was" line.
Again they didn`t even know there was supposed to be a heat shield until I started to look into things.
Curious though with the Cover off is there anything I should look for that would indicate something is out of whack (ie the bulb placement itself or the direction of the buldge of the bulb and weather that should be up or down), or anything else.
I am trying start from scratch, and take nothing off the table, as I don`t know what previous people have done over the years to it.
FM One spot always burned gels but no one looked into it, but now that we replaced the bulb in the other one, now both are doing it. Which is making this harder to pinpoint
Again thanks for all the help/
Soundguy99
 
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As if a target for a gun a little high, adjust the windage thru the front aiming pin. Bench focus is off! I wonder if the lamp isn't a little too far back from its reflector in also the cause. Download the manual and read it. This is step 1 in operating the lighting fixture.

I ran into some fixtures recently where the (+) rear wire was at too sharp an angle to get a wgood bench focus in lowering it further and that's why the bench focus was always high. Simple fix in adjusting that wire so it in bench focus doesn't bottom out for bench focus. Can be the same for the front (-) wire - though in those cases for at least a Trouper... I tend to try to trail that wire more aligned to the lower lamp support ring so as to not block more light.

Now that you have the heat shield appairently, how did that fair? Also a general note.... saturations of say over say 50% are often not needed or expected to work long. Are you oversaturated? Perhaps if you need a high saturation combine two less saturated gels in getting the same effect but taking up two slots.
 
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Just finished initial inspection/light service call to some 3Kw Strong Gladiator III followspots in addition to some SuperTroupers which were all donated or sold to a large promoter we do the service for. Seems the initial venu in addition to sending some employees to the spot booth to remove the lamps, than wrap them in bubble wrap and box them up in what ever boxes they could find.... - much more dangerous than just leaving them in for transport which isn’t a good idea but a better one at least if you don’t have proper storage for the lamps, was done.

They were also apparently told to remove the gel frames from the boomerangs. Were I donating spotlights, I would probably do that also given I believe most gel frames are standardized fixture to fixture, and having extra gel frames is a good thing. Fair enough. Unfortunately those staff removing the "gel frames" in the boomerang in the gel frames in the Gladiators... also removed the heat shield and even the UV assemblies. Fair enough again if one wants used spare parts. UV assembly is not transferable to other spotlights but trauma in a lot of money if not sent back or in all missing so as to replace gel frames and even entire assemblies - not told about. TBA if staff got too ambitious or if just the cost of getting the lights. The about $2K to fix four boomerangs in addition to other issues will determine if the spots are scraped or sold off. Spots are in good overall condition if they see a full service call. A shame to scrap but in limbo at the moment.

Difficult to save 3Kw spotlights with issues but overall in good shape but needing a serious service call to sustain them. That plus all have been cut down to their lowest yoke position so they only stand about 5' high = yoke spigots will possibly have to be replaced in addition to other parts including basically everything inside the boomerang if the parts are not returned and can be re-installed. Their auto ranging for wattage ballasts now serviced, are worth more than the spotlights for other venue’s in failing Super Trouper ballasts. Replacement ballasts are almost cost prohibitive given the amount of work and parts which also have to go into the spotlights so as to make them viable. Do the "factory fixed ballast" at times in indeed sending them back to Strong, but only when for a viable fixture. This for a 3Kw Glad III which is slightly more intense than a Super Trouper, but obsolete as compared to more modern fixtures in its range. To fix them and retain the ballasts as opposed to using them to replace bad Trouper ballasts .... a shame. Lights work per spec. or can in one case be easily cost effectively fixed.

$73.00 list price on the missing heat shield complete assembly. $11.00 for the heat filter alone.
 
Hey, ship: did they wear gloves when pulling the lamps? :)

Or would you just alcohol-wash used lamps in that situation as a matter of course?
 

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