Phoebus UltraArc II service manual needed.

[mcdork]

Does anyone have a service manual for the Phoebus UltraArc II Long Throw?

I've only been able to find the user manual for it, which doesn't include pictures/diagrams of the interior. The reason I'm asking is that ours doesn't seem to have the right dowser/shutter/iris assembly in it. The dowser/shutter work but seem to be too small for the beam (aperture is about 1.5" square) and the iris cannot close far enough to affect the beam at all because the operating lever collides with the rear lens assembly in its rear position. With the lens in the forward position, the iris still can't close because the iris handle slot doesn't have enough length.

The only way we can get a round beam out of it is to throw it completely out of focus.

If someone has the service manual (or pictures of the inside of a working one) I can go throw a fit at the"repair shop" that did the work on it under my predecessor.


I'll post some pictures of what I'm looking at later on.

 

[JD]

You're saying the iris cannot dial down to affect the beam coming from a 1.5 inch gate? Don't have a manual, but have worked on them in the past. Iris should dial down to about 1/4 inch or smaller. Sounds like somebody was playing around with this one, or improvised a replacement iris.

 

[David Ashton]

I have some of these lights, no manual but if you want photos of any sections let me know

 

[mcdork]

Correct, fully "closed" the iris opening is still more than 2.5 inches in diameter. The iris control lever moves thorough an arc a little less that 90 degrees with the cover on. To close fully it needs to move somewhere closer to 120 degrees which can only be done with the covers off, the handle removed, and the rear lens positioned all the way forward. Even then I'd say its still more like 3/8" in diameter.

David, If you could get me a couple photos of the dowser/shutter/iris assembly in one of yours I'd appreciate it.

 

[JD]

2.5 sounds more like the full open position! Any chance this thing got mounted 90 degrees off? 4 hole mount if I remember.

 

[venuetech]

I had an Ultra-Arc LT (first generation) and i recall that the iris itself did not have fixed mounting holes it was round, small tabs on the mount held the iris in place. The iris could have easily rotated from its normal position. I recall getting a replacement iris from Phoebus, when i talked to the fellow he told me that they had stopped using that type and he was giving me the last one they had on the shelf.

 

[mcdork]

Ok, here are pictures. First one is the whole thing with the cover off. The rear lens is as far back as it goes which puts it flat up against the iris.

Second is a close up of the lens and iris in the same position. The black bracket coming out the top is what the control handle screws into. It is in the fully "closed" position and is stopped by the top of the lens housing.

Last is the lens fully forward and the iris closed as far as possible. This can only be done with the cover removed though due to the range it has to travel to reach this position.

 

[JD]

I had an Ultra-Arc LT (first generation) and i recall that the iris itself did not have fixed mounting holes it was round, small tabs on the mount held the iris in place. The iris could have easily rotated from its normal position. I recall getting a replacement iris from Phoebus, when i talked to the fellow he told me that they had stopped using that type and he was giving me the last one they had on the shelf.

Looking at the pictures, I think that he's right! Move the iris itself so that the smallest aperture is correct with the handle position and tighten it up!

 

[mcdork]

I'll give it a shot next time I'm down there. Thanks.

 

[Les]

Agreed here too - looks like the iris needs to rotate a few degrees to the left (from the camera's perspective). Tighten it up pretty well. I think there is some hi-temp Loc-tite you could put on those tabs to keep things from moving again.

 

[venuetech]

Another thing to check is the UHMW guides that ride the stainless steel rods. The aluminum block that the moving lens mounts are based on should have that white UHMW bushing fully inserted. they tend to work loose as i recall.

I think the reason i had to replace the iris was that it had been installed rotated too far the other way and the leafs kept getting jammed by the operators, bending a leaf or two. So make sure when the top housing is on that the lever stops before the leaf crunch.

 

[mcdork]

I finally got down to the theater and re-adjusted the position of the iris. It now does cut off the beam, but it seems to be dimming it instead of irising in. I can get a nice hard edge when using the shutter and dowser, but there doesn't seem to be any position for the movable lenses that will give me a hard edge at the iris. So I think that the focus is so far to soft that you can't tell the iris is closing in. Could it be that the lamp/lens assembly is in the wrong position?

I was using a pretty short throw (~3 feet) when I was testing. Since this is an outdoor venue I'd have had to wait til dark to test it on the real throw, could that make a difference?

 

[JD]

3 feet is a bit too close to tell. In general, the position of the smaller lens sets the focal point. All three cannot be in focus at the same time, so usually, the iris gate is what you focus on. The chopper and dimmer are less important, and the dimmer works best when it is out of focus the worst. Again, 3 feet is not going to give you results for a test.

 

[mcdork]

The short throw was only due to the limits of the storage room. This thing is stored inside and the stand is kept outside on the balcony. It weighs too much for me to get it out there on my own. I'll be down there next week sometime and get it loaded up and test again.

 

[JD]

By the way, in photo #2, the small lens looks WAY too close. For a throw of 100 feet, I would move the forward most lens all the way forward, then move the rear lens to bring the iris in focus. If you cannot get a wide enough spot, then back the front lens up a bit and refocus. Your highest light output is with the forward lens far forward. As you back it off (for shorter throws) your light output drops.

 

[mcdork]

The photos just how the movement range of the smaller lens, it wasn't focused on anything or powered on at the time.