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Topic: Focus Problems

Christopher A Kerr
Film Handler

Posts: 43
From: Oakville, Ontario, Canada
Registered: Sep 1999

posted 10-13-1999 07:35 PM

OK, I'm stumped.

I have been showing The Sixth Sense for 2 weeks now and for some reason it keeps going out of focus at the reel changes. It doesn't happen every time, but when it does, as soon as the reel changes, the focus goes all to hell. I've checked the gate tension and it is still properly adjusted. I just can't figure it out. It's probably a very simple solution. Any ideas?

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Rick Long
Jedi Master Film Handler

Posts: 759
From: Toronto, Ontario, Canada
Registered: Nov 1999

posted 10-13-1999 07:46 PM

Give us some information about the type of equipment you're using and bulb wattage, ect. Does this happen on both Scope and Flat?

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Brad Miller
Administrator

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

posted 10-13-1999 08:13 PM

I'm wondering if you are a changeover house?

Does the focus gradually work itself in or out of focus...or is it an instant change when the splice goes through?

Does this only happen with "Sixth Sense"? Have you tried playing another print in that house since the problem emerged? Has anything changed...perhaps a service call?

And most important, Rick is right...tell us exactly what kind of equipment you are using. Someone on this forum will have a solution!

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Joe Redifer
You need a beating today

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

posted 10-13-1999 09:24 PM

It does not sound as if Christopher is running at a reel to reel house.

Try this: Make a giant loop with several splices in it and see if it goes out of focus at the splices. If it does, watch what happens in the gate when the splices go through. Perhaps it is jumping slightly out of position, even if the band tension is set correctly. Perhaps it is forcing the gate open a little bit as the thick splice passes through. Try pushing the gate closed before refocusing next time and see if that restores the picture. If so, you may want to check out your gate and make sure it is completely secure and not prone to wandering when a splice goes through.

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 10-13-1999 11:29 PM

When I first trained in the booth, it was in the 'old' 6-plex just pre-opening of the 17-plex I work at now. They had the 'old' Century proj. without turrets.
(You press the knob in to shut the gate.)

Well, the gate didn't shut tight enough and every time a splice went through you had to refocus. It turned out that the gate wasn't shutting all the way tight. If you made sure it was all the way closed, (Turning the knob with your hand after you closed it, instead of just letting it 'snap' shut.), you didn't have that problem.

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Brad Miller
Administrator

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

posted 10-13-1999 11:49 PM

Those old Century projector knobs have a spring that can be tightened to prevent that. Replacing the entire assembly is a cinch too...just two allen screws on top and bottom to remove and install a new one.

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Scott Ribbens
Expert Film Handler

Posts: 118
From: Los Angeles
Registered: Oct 1999

posted 10-14-1999 12:25 AM

There are a few more reasons that a Century (or Monee) gate dose not close all of the way. The gate support tube may be clogged with gunk (do not oil this as it just gunks it up even more in the future), it should be dry and clean. Second is the spring in the knob. If you replace the spring, follow the manufacturer's instuctions for tension as one of the major causes of the spring going bad is from over tensioning of the spring. Another cause could be a burr in the tube.

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Aaron Sisemore
Flaming Ribs beat Reeses Peanut Butter Cups any day!

Posts: 3061
From: Rockwall TX USA
Registered: Sep 1999

posted 10-14-1999 07:00 PM

Another thing to watch out for with Century and clones: Trap assemblies that are BENT out of alignment because somebody DROPPED them to the floor and then tried to 'cover it up'- Unfortunately, when the trap is dropped and bent this way the resulting picture is almost ALWAYS unfocusable, usually a 'good in the center but not the sides and vice versa' type of problem. The trap can be bent back into position (after disassembling the tension mechanism and lateral guide assembly) then being VERY careful when bending the 'ears at the top of the trap (you can break these very easily, be careful!), but the result is not always optimum. I have replaced several trap assemblies because of this problem. If I only knew WHO was dropping these things!

Another cause of the gate not closing completely, especially if the spring tension is good, is the trap side rails ( the 3/8" wide ones, not the bands) have gotten jarred out of position ( usually from the aforementioned dropping problem) or the screws that lock them in place just came loose...

Aaron

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 10-15-1999 03:23 PM

Arron,

I agree with all of that. We have two traps that are bent like that. The FRAME alone costs about $700. (Not inclding all of the guide wheels, rails and screws. -- Aperture changer not included.)

Studio guides (rails) are a B*tch! Sometimes I think the projector runs better without them. The AA-II at the Warner doesn't even have them! (Of course it's like comparing apples & oranges!)

All I can say is to do your best at realigning things. Unless your trap is REALLY bent up, you can usually get things 99% back to normal. Our technician said that ya' either replace it or live with it. (And you know mgt. isn't going to shell out $1k any time soon!)

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Christopher A Kerr
Film Handler

Posts: 43
From: Oakville, Ontario, Canada
Registered: Sep 1999

posted 10-15-1999 10:06 PM

I should have known better. Here are my specs:

- century CC projectors on simplex soundheads
- strong 5 tier platters
- OSRAM 2000w/h Xenon bulbs

To answer a few questions:

1. No, I am not a changeover house
2. I have tried out my test loops, and the splices do not effect the focus
3. I have checked the gate tension and I seems to be OK to me
4. This only happens on the Sixth Sense so I don't think it has anything to do with the scope/flat issue
5. I have inspected the trap and it is good condition

I've been watching it carefully and it doesn't skip out of focus everytime but as soon as I think its fixed and turn my back, sure enough it happens again.

BTW : I know what you mean about the gates being tricky on Century's and clones. We have two Century CC's but for a while we were running a Westar that we had on loan while the intermittant was fixed in one of our heads. You had to hold the guides while you closed the gate or it would jam against the side of the trap. Lots of fun.

Thanx
Chris

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Rick Long
Jedi Master Film Handler

Posts: 759
From: Toronto, Ontario, Canada
Registered: Nov 1999

posted 10-15-1999 10:10 PM

Any chance of this being a loose element in the Flat lens?

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Joe Redifer
You need a beating today

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

posted 10-16-1999 03:32 AM

Rick has an excellent point. We had this problem. Remove the lens or have your tech do it and shake it to see if there is any rattle. If so, time to fix the lens or get a new one. Or you can try swapping lenses with another auditorium of the EXACT same size and throw if you have one and see if the problem follows the lens.

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John Walsh
Film God

Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999

posted 10-16-1999 11:26 AM

Since it only happens with "Sixth Sense", could it have been damaged by a previous theater that ran c/o's and had one lamp too hot and distorted the print? Switching lens of the same focal length is a good idea, but you will probably see the aperture edge. Good for a test, though. On a slow night, swap the print to another theater. When the theater is closed, run it in flat and see what happens.

Or you could break down the film and then make it up again, only put the reels in this order: 2, 1, 4, 3, 6, 5, 7.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 10-16-1999 04:05 PM

Ah, since your projector is a Century CC which is a straight gate there is one thing to look at...

If the gate parts have worn or if your print is shedding....there will be a build up of dust in the gate area that may move when the reel change splice goes through and then wedge between the studio guides/trap and the film and cause it to pucker out slightly.

I have seen this on both Century and Simplex straight gates. It is normally caused by worn trap parts scraping the film to create build up.

This may not be true in your case but it is worth a look.

Steve

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Christopher A Kerr
Film Handler

Posts: 43
From: Oakville, Ontario, Canada
Registered: Sep 1999

posted 10-17-1999 10:57 AM

Eureka!!!!!

Steve you did it. My projector does shred slightly and I watched for th loose dust bits that you suggested and sure enough...

A little bit of dust collected at the top of one of the studio guides and when the plice went through I saw it dissapear. I stopped the projector and there it was, lots of dust on the guides. I cleaned it off and the picture went back into focus when I re-started.

Now, how do I keep this from happening again? I keep my projectors CLEAN and always have paid special attention to the trap, but how do I keep fresh dust from getting sucked in during the show?

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