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Topic: Technical Questions

Paul Rich
Film Handler

Posts: 56
From: Murfreesboro, TN, 37128
Registered: Nov 1999

posted 01-06-2000 03:57 AM

Hi, this is my first post to this forum and hopefully not the last. I'm on the floor staff at a 3 month old Carmike 16 plex.

I have noticed several things that I was wondering about. First, I have noticed on one auitorium that prints shown in it end up having vertical lines on the film. I haven't noticed this on prints that started in other auditoriums. It's real bad and annoying. What's the problem?

Second, another auditorium has a problem with flicker. Is this because of the bulb? Films are always not framed properly in this auditorium either. They're too high.

Thank you.

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 01-06-2000 04:02 AM

Tell us everything you can about the booth at your theater. The vertical lines are scratches in the film due to the projectionist misthreading, failing to properly clean the projector or there is something mechanically creating the scratches. Commonly this is the big screen with the "70mm" projector and the extra sets of sprockets confuses some projectionists.

The flicker could be caused by the bulb, perhaps there is an open diode in the rectifier, lots of things. As to the framing, there is a control generally labeled "frame" that the projectionist can turn slightly in one direction or the other to properly center the image vertically. If it is not centered horizontally, then this is an entirely different problem.

Let us know make, models, anything you can about your booth and we'll help ya as best we can.

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Ari Nordström
Master Film Handler

Posts: 283
From: Göteborg, Sweden
Registered: Jan 2000

posted 01-06-2000 07:15 AM

The flicker could also be caused by a loose main mirror. I ran into this problem a couple of years ago, when working extra at a triple-screen theatre in town. Their largest screen flickered its way through shows in an irregular, rather anoying manner, and I couldn't stand the thought of having anyone pay for a show in that auditorium. So after checking the condition of the bulb, I had a quick look around in the lamphouse and discovered that the mirror wasn't secured; it could move several millimeters in every direction.

It was easy enough for me to replace the washer and tighten the screws between shows, but I don't recommend it to anyone not used to messing around in lamphouses since there is always a risk connected to opening a lamphouse.

Of course, a thousand other things could also cause the flicker, so good luck!

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Paul Rich
Film Handler

Posts: 56
From: Murfreesboro, TN, 37128
Registered: Nov 1999

posted 01-06-2000 03:58 PM

I know we have Christie projectors, but I'm not sure of the exact model, and autowind (I'm guessing AW3R).

I'll find out tomorrow.

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Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 01-06-2000 04:27 PM

Well, I don't think your Christie's are old enough yet, but when the shutter belt starts to wear out the image will have a stroby type of flicker. The entire screen flickers, not just a portion of it. If it is only a portion of the screen flickering, then it is the xenon bulb. If the shutter belt was installed too tight at the factory (unlikely) or during install (possible) then it could wear down quickly as a result. Depending on the tension, you will usually have about 2 weeks to change out a shuuter belt when you notice it flickering before it breaks completely.

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