This is topic need advice on xenon alignment? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Brad Haven (Member # 954) on 03-27-2002, 05:52 AM:
lamphouse : super lume-x
xenon : ushio 1600k
I am having problems aligning the xenon!
I am left with dark shadows on the top left and right, with bottom half being evenly lit. Using the bulb adjustment controls i have lifted the light as high and as even as possible, the control wont lift any higher!. The only possible solution i can see, is to adjust the height of the yoke?. Would i be right on this or can anyone think of another reason/solution?. Also to lift the light (on screen) higher, would i need to raise or lower the yoke?.
I have changed/rotated xenons before (in other cinemas) , but always without incident, but my experience is limited!
If anyone could help with some words of wisdom, they would be greatly appreciated?
This problem has been in this cinema for a couple of years, but no one else could/would fix it! The person who used to maintain the xenons has since left the company.
Posted by John Pytlak (Member # 331) on 03-27-2002, 06:50 AM:
Is the lamphouse itself properly aligned with the projector's optical axis? Is the distance from the reflector to the aperture correct?First step is checking alignment and distance:
http://www.muellersatomics.com/alignotron.htm
------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
Posted by Brad Haven (Member # 954) on 03-27-2002, 07:06 AM:
i dont believe that it has been properly aligned.
i hope to get our local tech in to do an alignment some time soon.
i dont believe that my company would fork out for the align o tron , but i could give the string method a try, atleast it would give me an idea of how close i am?
Posted by Gordon McLeod (Member # 33) on 03-27-2002, 07:52 AM:
Once you have done the string method look at the bullseye on the screen with no lens and the rear alignment in the centre position then move the yoke to centre the bullseye.
Then you will have some adjustment at the rear end of the lamphouse for fine tunning
Posted by Frank Angel (Member # 248) on 03-27-2002, 08:43 AM:
And once you do all those things....use the string, use the big stick with the thing that sticks in the lens holder, and you get that round black spot to sit perfectly centered on the screen when you have the lens out, xenon lovers will make it sound like that will get you a completely even, corner-to-corner light. Well, my friend, that would only be true if you were aligning a CARBON ARC lamphouse. With xenon, you may have to resign yourself to settle for uneven light, mottled with dark spots and hot spots that just move around the screen while you twist and turn the alignment nuts until you're blue in the face. I mean, how much "alignment" can you do with a lamphouse that can only sit one way on the pedestal? Either the screw holes in the lamphouse line up with the slots or they don't -- it's not like you have any fine adjustments left and right. The only thing you can really adjust is the distance from the center of the bulb to the center of the aperture plate. And believe me, you can have that distance correct down to the millimeter and that won't guaranttee you anything in terms of no hot spots or dark corners. And lastly, don't fall into the trap of thinking, "Oh, geez, I must be doing something wrong....it must take a 'tech guy' to align this" HAH! You ARE the tech guy. What...you think he's got some magical powers that you don't have? He knows some special "tech controls" in the belly of the lamphouse that's gonna make it put out an even, beautiful light? Maybe in some mythical world, but when it comes to xenon, I'll bet you're pretty much are doing it all right -- it's just a crappy lamphouse. IT AIN'T YOUR FAULT! (See what happens when I log on before I have my morning coffee?) 
Sorry guys.
Frank
Posted by Jeff Taylor (Member # 443) on 03-27-2002, 08:52 AM:
C'mon Frank. Stop pussyfooting around and tell us what you REALLY think!
Posted by Dave Macaulay (Member # 813) on 03-27-2002, 08:52 AM:
The SLX uses the little pin clip to set the height of the yoke, and it usually comes close to being correct if you use the right hole. The Ushio CX16 is physically the same as the Osram 1600HSC and uses the brass threaded-on cathode adapter and the chrome anode extension, correct?
For this setup the pin must be in the bottom hole - thus the yoke is at its highest "preset" position. (page 12 in the newer SLX manual)
Unless the lamphouse has been maladjusted via the threaded rod inside, or it has a new type adjustable mirror that has been maladjusted, this should give a well centred beam right down the design axis.
Try removing the main lens and aperture plate and projecting white light on screen (motor running!). With the cathode adjustment roughly centred you should be able to get a basically circular pattern with the light brightness symmetrical around the centre, excluding the cable shadow. That happens when the lamp arc is centred in the (properly shaped and not bent or dented to hell) mirror and near the focal point. If the cathode adjuster is right at one edge to do this, you can move the anode yoke the same way to correct it. Up is easy, down you remove the pin, sideways you turn the yoke so it isn't perpendicular to the mirror. Don't get anal about the cathode being perfectly in the centre of its adjustment.
The centre of the round light pattern on screen must be very close to the centre of your scope screen. The 1.85 masked screen area may be off center depending on what masking edges move but the scope area is the important one for this. If it isn't centred - the lamphouse is misaligned with the projector head.
If you have the lens and mirror adapters and want to use the string method give it a try.
An important thing to remember is that the aperture is one of the alignment points.
The string reflection should match the string image all around, with the string passing through the centre of the film aperture. The old fixed mirrors made this hard to screw up, the new adjustable one lets you get the string looking good with the lamphouse axis offset to the projector optical axis.
The aluminum yoke adapter thingy for the string method is pretty useless for setting the yoke, but handy for aiming the adjustable mirror. The string should look "right" in the mirror, and go through the centre of the yoke adapter hole with the yoke square to the mirror and set with the pin in the bottom hole (highest yoke position!). Then align the lamphouse and projector without changing the mirror settings.
Posted by Greg Mueller (Member # 17) on 03-27-2002, 09:07 AM:
What you can do to help with your alignment is to make an "intermediate" or "adapter plate" which would go between the lamp house and it normal mounting place. Put slots in that adapter plate so you can move the lamphouse from side to side. You will then be able to move the lamphouse forward and backward and side to side. You can adjust in the third dimension by using washers or other little blocks to raise and lower the lamphouse. Another problem I ran into was that although the lamphouse appeared to be straight it was really skewed to the side. It took all of the available slop to get it really lined up. The worst offender was the aim of the reflector. That single thing wound up being most of the problem. When mine was replaced (blown bulb) the tech simply screwed the refector aiming screws down tight against the springs. That made the aim way off. The Super Lume-X (the one with the spring loaded reflector) really benefits from using a laser type device------------------
Greg Mueller
Amateur Astronomer, Machinist, Filmnut http://www.muellersatomics.com/
Posted by Pete Naples (Member # 761) on 03-27-2002, 09:54 AM:
Frank, since when??I've never seen a pedestal that DOESN'T allow you to move the lamphouse table up, down, left and right, as well as back and forward. Most pedestals are designs from the carbon arc days anyway. The Westrex one that is common here (probably similar to a simplex or century) has a table that is adjustable indepently of the rest of it. Much the same way as the current Strong pedestal does. With regard to evenness of light. I have Lume-X all over the place here. Some of them will actually give you 16fl all over the screen. And those ones we end up pulling back the bulb focus because it doesn't look right, it's too flat. We pull the focus back to a point where the corners drop off, but are still within SMPTE spec. Can you explain to me what is different between aligning a carbon lamp and a xenon arc lamp? Both have a mirror which needs to be aligned to the arc, and both must be aligned to the optical centre of the machine. If you've only ever seen xenon light as you describe, then you have seen some very poorly installed and aligned lamphouses.
Posted by Greg Pauley (Member # 503) on 03-27-2002, 10:14 AM:
"I mean, how much "alignment" can you do with a lamphouse that can only sit one way on the pedestal? Either the screw holes in the lamphouse line up with the slots or they don't -- it's not like you have any fine adjustments left and right. "Frank, What type of pedestal are you working with? Every pedestal we use have horizontal and vertical adjustments for the position of the lamphouse and you can easily have the lamphouse out of alignment. The fact that the holes lineup with the lamphouse means nothing as far as the alignment of the lamphouse. Brad, how old is the reflector? I have found a few metal reflectors in our Super Lume-X have warped due to excessive heat and will not allow even light regardless of how much you align the lamphouse. If you have another Super that has a good light output, you may want to switch the reflector to see if the problem moves with the reflector. My experience with Super Lume-X is they give a good even light output whenever they are align properly and have a good reflectors
Posted by Brad Haven (Member # 954) on 03-27-2002, 10:16 AM:
thank's for the very interesting comment's/suggestions.
this morning when i rotated the other xenon i was very pleased with the result, very even light across the entire scope screen, the entire process taking just 5 mins, 3000hrs down and still plenty of gas left in the tank!
well... i've printed out the posts so far and i'll take them into work tomorrow and work out my plan of action!
thanks
brad
Posted by Brad Haven (Member # 954) on 03-27-2002, 10:24 AM:
greg,
As the cinema was set up about 10 years ago , i'd say 10 years?.
Would a warp be visible to the eye or only by the test you suggested?.
i'm not sure of how to swap a reflector, but there are people around in perth that would help if needed?
Posted by Greg Pauley (Member # 503) on 03-27-2002, 10:45 AM:
Brad,Pretty easy to remove the reflector on a Super Lume-X. You will need to remove the bulb using protective gear. There are 4 screws that hold the reflector to the mount from the back side of the reflector. Remove the screws and pull the reflector (there are 2 aligning pins that the reflector sit on). After you remove the reflector, hold it like a bowl and look for any obvious defects. The ones I saw were all deformed around the cutout on the back of the reflector. Should be pretty obvious if they are bent. Also, look for any discoloration of the surface of the reflector. If you see a lot of blue or green color, it's time for a new reflector.
Posted by Gordon McLeod (Member # 33) on 03-27-2002, 04:04 PM:
Actually some of the Simplex LL3 bases (or is it LL1) had minimal lamphouse adjustment
Posted by Josh Jones (Member # 447) on 03-27-2002, 09:43 PM:
Gord, the LL-1 was the heavy cast-iron bastard wasnt it?
the LL-2(sheet metal) is more common, never heard of an LL-3as for the xenon and carbon thing, all of the light in a carbon arc lamp comes from the glowing crater. in a xenon, it is the plasma ball giving off all the light. collecting light from a wondering plasma shere is difficult. they could take all of the light from the anode, but it would look quite orange on screen 
Josh
------------------
"Film is made of silver, video is made of rust"
'nuf said
Posted by Paul G. Thompson (Member # 655) on 03-27-2002, 09:47 PM:
Josh, the LL-1 is the big heavy bastard. I have one, do you want it? It is something neat to trip over. It won't move! It even has the RCA goose neck on it.
Posted by John Walsh (Member # 168) on 03-27-2002, 10:19 PM:
I been lucky enough to get pretty good alignment out of most every xenon I've delt with. Less experienced people tend to do something like be a little off one way on the bulb-to-reflector alignment, then compensate by throwing off the reflector-to-lens alignment.OTOH, those vertical lamps with the auxiliary mirror - I didn't work on very many, which is good because I don't think I ever got one completely right. Luckly for me, they were pretty much passe by the late 70's when I started working a booth
Posted by Paul G. Thompson (Member # 655) on 03-27-2002, 10:42 PM:
John, there was one base made by RCA that the lamp table was basically non-adjustable. I don't know what the model number was, but it was so far out of kilter I had to make the target adjustment by actually shimming the mirror in the lamphouse. It was a real chore, and took a substantial amount of time just to get it in the ballpark.I abandoned the base when we closed the theater and dismantled the booth. It promptly went into the dumpster along with a broken LL-1 that was dropped when removed from the Lido Theater in Mount Vernon before Plitt went bankrupt. The LL-1 was so heavy I had to take a sledge hammer and make a bunch of little LL-1's out of it so it could be moved. That was before I figured out how to dismantle it into manageable chunks.
Posted by Dave Macaulay (Member # 813) on 03-27-2002, 10:50 PM:
The easiest way to check a reflector for damage is to take a mini-maglite and remove the whole front part so the bulb is on and sticking out.
Obviously if the mirror has dents or other serious damage you already know it's screwed up...
Hold the mirror securely pointing squarely at a light coloured surface (wall?) or leave it in the lamphouse with a sheet of paper at the dowser (perpendicular to the mirror).
Slip the maglite bulb-first into the vertex hole from the rear.
You will see a pattern of light on the wall or paper. Moving the bulb up/down or sideways will distort the circular symmetry of the pattern, get the best looking concentric circles you can. Moving axially in and out alters the size and focus of the pattern. (rotating the minimag gives an idea of what effect the filament shape has, this effect should be ignored)
With a perfect reflector, you will be able to produce - with the bulb exactly on the mirror's optical axis and close to its focal point - a pattern of perfectly concentric perfectly circular rings. A damaged reflector will not be able to do that - no matter where the lamp is you will see a messy pattern, with blobs of light and/or figure-8 patterns all over. Mirrors without obvious problems can still give really bad results, and the bad results here correspond to bad results on screen with a xenon lamp.
Perfect reflectors are rather rare but a good one will have a near-perfect pattern with some distortion on the inner and outer rings but mostly good circles.
Why this pattern of circles? The mirror is not a single parabolic curve, it is a blend of many slightly different such curves arranged in successive rings from the vertex to the front edge of the mirror - so it doesn't focus light to a point, rather it focuses to a circular pattern made up of rings of light each focused by one of the mirror sections.
The minimag filament is considerably smaller than the arc plasma area thus the light rings are narrower. Instead of blending together into a bright spot, the rings are made individually visible. The rings' curves and sizes are engineered to match the plasma ball size of the lamps expected.
(bonus: if you set a bit of paper in the aperture you can check if the mirror is pointed exactly on the aperture centre - the centre of the concentric ring pattern is on the optical axis of the mirror)
Posted by Frank Angel (Member # 248) on 03-29-2002, 01:15 AM:
We've got the big Simplex bases with Peerless Magnarcs sitting on them. These pedestals are very simple, very dumb, big slabs of cast iron that don't want to be moved. And unless I am missing something, the ONLY adjustment that can be made with respect to the lamphouse and the base on which it sits, is the ability to slide the lamphouse foward and backward. No way to slide it to the left or right with respect to the head aperture. I always assumed because of this, that the industry must somehow have "universal" mounting dimension, like arms and magazines to the top of projector heads....if you can get the bolts to match the lamphouse threaded holes through the slots in the base, you were dead center. Bad assumption? No matter, the carbon arc focus on these machines produces a very even light and the mirror adjustment knobs do exactly what they are supposed to do -- they move the entire light ball EVENLY up and down or left to right, never a hotspot or uneven illumination -- UNLIKE the Xetrons which are in our smaller theatre, where when you adjust the mirror, the light on the screen looks like it is twisting and just moving the hotspots and dark spots around. The pedestals that the Xetrons sit on (no name on them, but I think they are made by Kelmar) also seem to have no lateral adjustment whatsoever and there again, the mounting holes in the lamphouse seem to be able to mate in only one place. These were already set up when I got to that venue and by a big, reputable cinema service company here in NY, so I assume that at the very least, these tech guys got the gross physical alignment of the lamphouse on the base correct. But any adjustment of the mirror or focus distance on these babies never gets rid of the slight dark spot, just moves it around -- and I recognize that "figure 8" that Dave M. mentioned. I've never had such trouble with the carbons -- maybe the optical system of the carbon lamphouse is more forgiving of slight optical misalignments? Anyway, with all the great tips the guys here have been posting, it becomes pretty obvious to me that these tips didn't come from a Strong lamphouse manual. None of this stuff seems like it is part of the lamphouse design. Seems like they could design some of this alignment minutia into the lamphouse itself to make setting the things up reliant a little less on years of personal experience and a little more on well placed, intuitive knobs and adjustment screws.
Frank
Oh yah, PS -- in the park venue I've got ORC lamphouses on the same Simplex dumb pedestals. There I am happy if I can even get the lamphouse screw holes to line up with the slots in the base. Forget about any Left/Right alignment. Lucily, both these put out fairly even light, but not perfect....not as perfect as I feel I could easily get with a couple of Core-Lites sitting on top of those bases.
Posted by Brad Haven (Member # 954) on 03-29-2002, 05:24 AM:
Well... it's now looking better than it has done for the 2 years that i've been at this location!. It's not perfect, but it's not far off!.
after having a good long think/look at the problem i decided to make an adjustment to the yoke, it was close to the A position, but i raised it slightly and made a slight twist, to centre the light more evenly. The way i'm looking at it now, it's seem's that 3-4 wrong's kind of make a right?, i think i will get the tech to do a proper alignment, he's coming in soon to replace the framing on the ballantyne for the same cinema. I know it can be better and i'm not going to be happy until it's perfect!.
So thank you for all your post's, once again i am a better projectionist than i was the day before!
thanks
brad 
dave macaulay , i tried to email you, but your email address doesn't seem to be working? , just wanted to say thanks!
Posted by Pat Moore (Member # 380) on 03-29-2002, 06:52 AM:
There are two keys to proper xenon alignment. First is is the primary alignment of the reflector in relation to the lens's optical axis and the film plane. Second is proper focus of the xenon lamp within the reflector. Assuming the reflector is initially in the right place, that position will never change unless the reflector or projector changes, so primary alignment is really important to allow the system to operate at peak efficiency.Working Distance is the measurement from the film plane to some reference point of the reflector -- with Strong equipment, that's from the hole in the reflector to the film plane, and for Super Lume-X 11" reflector that WD should be about 25-3/4 inches to the aperture plate.
Once WD is correct, then you need to get the reflector on the same optical axis as the lens. The laser is a great tool for this and centers up the reflector really well. The string simulates the laser and does a nice job to show you what the reflector's optical surface is actually doing.
Once this primary reflector alignment is complete, then it's getting the bulb in the right place. This is generally pretty easy using the focus controls of the lamphouse, assuming the anode (POS) support is in the right place. Lamps from 700-1600 watts all use an anode adaptor in the Super Lume-X, so that should be the highest adjustment point of the anode support for all those lamps. For 2kw and above, the anode of the lamp itself is supported so it needs to accommodate the varying ferrule diameters of the xenon lamp manufacturers -- and they vary quite a bit depending on seal designs and such. I usually adjust that anode support just as I look at the string alignment -- get a viewing angle looking at the front end of the lamp on the reflector's surface, and adjust the height so the anode "covers" its image on the reflector. That will get you close enough that the focus control can make any fine adjustments required -- there's LOTS of adjustment room there.
Looking at the light on screen without the lens tells you a lot too. The black rings mentioned before (good post, by the way) should be circular and generally concentric. Anything resembling a "figure 8" means the reflector got whacked or is really deformed -- chances are pretty good the light's poor on screen.
Brad -- I took a quick look through this thread and did not see if you did try the string alignment just to see where things sit. The string is a quick way to see if the reflector is actually aligned where you think it is. Ideally you'd use a laser first, but the string might help a bit IF you feel the primary alignmemnt of the lamphouse is not correct. It sounds like you are closer to proper alignment though.
Even the old cast iron bases generally had some method of adjustment. If the lamp table really doesn't move, chances are there are provisions for adjusting the location of the soundhead & projector, even if it was just loosening the bolts and moving it.
Carbon arc optics are more forgiving, yes. Take a look at the arc flame -- it's HUGE compared to the plasma ball of a xenon lamp. Reflectors were generally very "slow" optically -- you see that in the shallowness of their curves. Xenon optics are totally different, based on maximum collection of light from that relatively small plasma ball of the lamp. They are also "faster", usually f2.1 or less. So yes, alignment of the xenon system is probably more critical, but their performance potential is also higher if properly aligned.
Early xenon optical systems had some "adjustment on the fly" provisions for the reflector built into them, but that proved to be more trouble in the long run. In the 70's the two-piece lamphouses, such as the Super Lume-X and virtually all others, fixed the reflector in place. The theory was -- and still is -- that if primary alignment of the system was done correctly, it never again needed adjustment. Properly aligned, these lamhouses could put out a great, even field of light.
If there were no other provisions on the pedestal for alignment, it wasn't unusual to shim as required. That was usually getting the lamphouse "up" a little, as the Super Lume-X was designed to be just short of the 9-1/2" optical height standard the industry had settled on.
Phew -- time for that third cup of coffee...
Pat
Posted by Brad Haven (Member # 954) on 03-29-2002, 09:09 AM:
hi pat,
no , i didn't get to do the string test, time has been a problem around this holiday period, i only had time to make slight adjustment's to the yoke.
we have a VIP base and while bolted down, we have complete freedom to adjust in any way.
about 6 months ago my former/future chief (a long story!) and i replaced the ballantyne head using a ruler and a couple of coins for alignment and he promised that when we get our framing replaced he would have it all properly aligned again by our tech (please note that our alignment problems have been there for a couple of years atleast!), so, beacause i am now alot closer/acceptable, i might wait for our tech who has all the eqiupment to do it right.
Posted by Pat Moore (Member # 380) on 03-29-2002, 10:55 PM:
Sounds good, Brad. Let us know what happens...Pat