This is topic Shutter Timing ? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Glenn Conatser (Member # 970) on 05-01-2002, 02:39 PM:
Hello Everyone,
One thing i still have not learned is how to time a shutter. Can someone explain the procedure. Im having a real problem in one of my auditoriums and need to learn this. Projector - Christie P35c
Lamphouse - Christie 2k
Thanks,
Glenn
Posted by Paul G. Thompson (Member # 655) on 05-01-2002, 03:00 PM:
If you have to time the shutter in a P-35, you might check the belt and the pully. Chances are,they are both shot! That is probably the reason why it jumped time. I never timed one, but if you check the manual on how to change the belt and pully, I am certain it will step you through on how to time it.
Posted by Glenn Conatser (Member # 970) on 05-01-2002, 03:31 PM:
Thanks for the quick reply Paul. One of the belt tensioners came loose and my tech talked me through how to take care of tightening up the belts. Im in luck though, someone is coming by to go over this in a couple of hours. So i should be ok. My tech is on vacation and im trying to avoid calling him unless absolutely necessaary.Thanks Again,
Glenn
Posted by Randy Stankey (Member # 64) on 05-01-2002, 04:43 PM:
Christies aren't too hard to time-up. If you know how to change (and retension) belts you are half way home.Take out the trap and remove the cover(s).
Check the belts for wear. Tighten or replace if necessary... OR just replace it anyway. If it's gone out of time, this is the prudent thing to do.
Turn the "timing knob" until the projector is in time, just like when you go to thread. Carefully inch the knob until you go exactly TWO sprockets past the "rest" position. (Place the tip of a pencil against the outboard bearing arm to act as a landmark.) Don't let the projector mechanism move out of this position! Have somebody hold the knob, or whatever, if you think you need to.
Loosen the shutter blade from its shaft with the long "T-Handle" Allen wrench. (Should have been included in the tool kit that came with your projector.)
Rotate the shutter on its shaft until the "cross hairs" etched onto the blade are centered EXACTLY in the aperture. (As seen from the projector, where the trap should be.)
Tighten the screws back down.
Rotate the timing knob and check the timing... Repeat steps above as necessary in case you didn't get it right the first time.
Put a couple drops of Christie (Panef) belt dressing on the shutter belt.
Buckle the projector back up and test it.
Posted by Brad Miller (Member # 2) on 05-01-2002, 05:03 PM:
Randy summed it up well, but of course there are always more than one way to get the job done. There is one thing that has not been mentioned in this thread that is very important, and that is the specific belt tension.Before you see the shutter is in time and decide your job is done, grab the holdback sprocket's knob with your right hand and hold the shutter still with your left hand. Now without the force of Arnold Schwarzenegger, but more than the projector would ever put on it, try and turn the inching knob. Does the belt jump teeth? If so, it's not tight enough. If it doesn't, is it too tight???
That being said, the easiest way I have found to time the shutter is to skip all of the prep work Randy described and just get the belt on. On the non-operator side there is a pulley that is mounted with 3 allen screws. Simply loosen those so that the pulley falls most of the way down and put the belt on. Then move that pulley back up so the belt is loose, but just barely tight enough that the teeth of the belt will mesh with the teeth in the pulley. Then tighten those allen screws just enough so that you can move the pulley up and down, but not so much that it will fall from gravity. At this point, check your timing. If it is off, just hold the inching knob still with one hand while you "bump" the shutter into time. So long as the shutter is blocking the path of light during the intermittent's pulldown, you are in time. (Of course do not have the xenon lit during this.) Now raise the pulley in the back to get the appropriate tension and do the test like I described in the first paragraph to make sure it is at the optimal tension.
Remember, you want that belt as loose as possible without it able to jump teeth, otherwise it will wear out FAST! I have several projectors running with belts I put on it over 3 years ago by using this technique. Your belts and pulleys will last a lot longer.
Posted by Dustin Mitchell (Member # 372) on 05-01-2002, 06:39 PM:
Does the P-35C (Glenn's projector) time any different than the P-35GP?
Posted by Will Kutler (Member # 770) on 05-01-2002, 09:56 PM:
If you really bust ass and the picture goes down, the Christie P35GPS can be retimed and up and running within a matter of a few minutes. Been there, done that!Like Randy said, a LONG HANDLED ALLEN (T-HANDLE) WRENCH sure makes life easy!
As for correct shutter/jackshaft belt tension, the belt should barely touch itselfe when squeezed together between the jackshaft and shuttershaft.
When you tighten up the shutter, make sure that it is not too far forward or aft on the shutter shaft otherwise it will interfere (hit) the projector.
Should you decide to replace the old style aluminum pulleys with the newer style steeel ones..BEWARE..many of the set screws are Lock-Tighted in and can be a BEAR to remove!
Finally, remove the gate at least once a week for cleaning! At the same time remove that little belt cover on top of the gate and clean the belt and pulleys! A couple of fresh drops of belt dressing once a week after cleaning---and I said just a couple of drops---DO NOT FLOOD! will really help out! Apply the belt lube with the machine off, and gently/slowly rotate the machine through via the pull down knob to distribute the dressing...then reattach the gate...
Posted by Randy Stankey (Member # 64) on 05-01-2002, 10:55 PM:
I don't know how many times I would go into a booth, ostensibly to do a quick "10 minute" job, and spend an hour simply because I couldn't find the right tools! Those "T-Handles" really change the way you look at making repairs like this. You'll wonder why you ever farted around with regular Allen wrenches all this time. I liked them so much I went out and bought myself a set of those babies.You SHOULD have a set of every type of Allen wrench needed to fix a Christie projector... T-Handles, Metrics and Ball-Drivers.
Here's what I did... I went into the cash office and "borrowed" one of the blue zipper bags that they keep their money in. It's just the perfect size to hold the dozen or so wrenches in your "Christie Kit". Toss in a couple of screwdrivers, etc and you have just about everything you'll ever need! 
Keep these babies in a safe place and treat them like gold! 
If you you are in a pinch and need a certain wrench you'll be glad you have them!
Back on the subject...
I agree about the belt tension. The way I did it was the way you did it, Will. Pinch the belt together. If you are just able to touch them together you have it right.
Posted by Leo Enticknap (Member # 534) on 05-02-2002, 07:17 AM:
Yet another word of agreement! I've never used one of these projectors, but on the only 'rubber band machine' I had any serious experience with (the Vic 5), then (i) the appearance of ghosting was symptomatic of the belt being knackered, and (ii) getting the belt tension right made a big difference to the useful life of both the drive belt and the shutter gearbox.
Posted by Pete Naples (Member # 761) on 05-02-2002, 12:28 PM:
The same holds true for the Westrex 7000, another rubber band machine(actually it's a steel-reinforced timing belt), whilst it hasn't got that money spinning shutter gearbox to wear out, correct belt tension is vital if the thing is to run without slipping a tooth or two.
Posted by Will Kutler (Member # 770) on 05-02-2002, 05:35 PM:
Randy...At the theater where I worked, it was a 20 screen with two booths. In each booth I constructed a large "shadow board" for tools. Each tool had its own outlined place. What I do recommend is that the boards be inspected (and all tools accounted for) during shift change-over--military style!
Posted by Randy Stankey (Member # 64) on 05-02-2002, 09:08 PM:
I had one theatre that had a peg board like that for its tools and parts. They were quite well organized. In fact, if I got a call from them I knew they had a REAL problem. So much so that when the phone rang and I saw the caller ID I would say, "Oh, Shit!"I wish more theatres were like that.
Posted by Michael Gonzalez (Member # 593) on 10-10-2002, 08:44 PM:
When installing a new timing belt, does it matter which direction you twist the belt (either toward the screen or away from the screen)? If so why? I can't see how this would make a difference but other people seem to think so (though they can never seem remember which way they are "suppose" to twist it).
Posted by Dustin Mitchell (Member # 372) on 10-10-2002, 10:03 PM:
If the belt is twisted incorrectly the shutter will spin in the opposite direction. Best way to remember which way to twist the belt is to look at the way the old one is twisted before you take it off, or if the old one broke look at one on another machine.
Posted by Michael Gonzalez (Member # 593) on 10-10-2002, 11:17 PM:
OK but now what does it matter which way the fan spins? Whether it spins clockwise or counter-clockwise the timing is still going to be the same and thus not effect the presentation. Now it was suggusted that if it is turned in the wrong direction (the belt) it will rub against the film-gate and thus wear out quicker. Does anyone know if thats the case?
Posted by Paul G. Thompson (Member # 655) on 10-11-2002, 02:55 AM:
Fan?
Posted by Matt Close (Member # 996) on 10-11-2002, 04:49 AM:
Sorry if this doesn't really belong in this thread ..... BUT,I use the Monee (Century knock-off) projectors, and I have a problem with travel ghost. If I totally get rid of the ghosting at the top of the frame, then I have ghosting at the bottom, and vice versa.... The best I can achieve is a little big of travel ghost all over. Do I need to adjust the blades themselves? I see the physical area of the shutter blades can be varied .... would this help matters?
Posted by Michael Gonzalez (Member # 593) on 10-11-2002, 10:33 AM:
Sorry shutter blade. I got used to calling it a fan from working with ballantine projectors because the shutter blade on those looks like a fan. Anyway what does it matter which way the shutter blade spins as long as the timing is the same since the blade is symmetrical.
Posted by Dustin Mitchell (Member # 372) on 10-11-2002, 03:07 PM:
To be honest I'm not sure if it does matter. I seem to recall I put the belt on backwards once and there was ghosting. I thought the blade was timed correctly, but maybe I was wrong.*shrugs*
There might not be a difference, then again there might be. Unless there is some sort of advantage to twisting it the other way I'd rather just do it how the manufacturer intended.
Posted by Michael Gonzalez (Member # 593) on 10-11-2002, 07:18 PM:
Then what is the right way according to the manufacturer? Toward or away from the screen?
Posted by Gordon McLeod (Member # 33) on 10-11-2002, 09:25 PM:
you may need a wider shutter blade
Posted by Dustin Mitchell (Member # 372) on 10-11-2002, 10:16 PM:
It should show you in your manual. If you don't have one you can download one from the manuals section of this site.
Posted by Jon Bartow (Member # 241) on 10-11-2002, 10:32 PM:
Matt,
Measure your shutter with a protractor. what do you get? IIRC 100deg is the "normal" Century shutter. However there are "Drive-In" shutters around that are a bit smaller (90deg?). If the shutter that you have is adjustable try expanding it to its maximum (make shure to check the timing after changing the shutter size).
Posted by Matt Close (Member # 996) on 10-13-2002, 10:55 PM:
Thanks Jon ... I'll check that ......
Posted by Randy Stankey (Member # 64) on 10-14-2002, 03:44 PM:
In the Christie Projector (Most other ones, too.) The shutter should spin OPPOSITE the direction the film is going... In other words, it will spin clockwise when viewed from the rear of the machine (Or counter-clockwise viewed from the front.)The easiest way to describe it in words would be to hook the belt under the bottom of the shutter pulley, then twist the part that's nearest you toward the front of the projector.
OR... you could just look at this picture...
Posted by System Notices (Member # 2357) on 08-05-2010, 02:08 AM:
It has been 2851 days since the last post.
Posted by Monte L Fullmer (Member # 2797) on 08-05-2010, 02:08 AM:
Gonna bump this 8 yr old topic up to the present day due to a search that I did, thus please forgive me:
I had to do a search on this topic that happened to me tonight on a Christie belt replacement and had problems like crazy until an almost major reinstall of parts finally cured the problem:
P35GPS - love these units. They don't have the swing-out motor mounts.
I can do a belt changeout in 15 minutes on these units without a hitch - including the pinch method that Brad mentions in this post on the shutter belt.
Tonight, while at the 14plex, I was doing some preventive maintenace while operating-which includes some belt changes.
Thus, got 4 machines done without a hitch until my 5th one and all hell broke loose.
Got the belts installed, hit the screen with the picture and horror was present on the screen: shutter streak oscillation-meaning it would be in time then horrible streaking would follow and then back in time.
Shut down the projector and rechecked my timing-which was totally way off. Thus, retimed the shutter, did the test and continued..and again streak oscillation.
Figured I had a defective double side belt. Replaced it with another one which proved negative-still had the problem.
(we had to cancel the show, but luckily, only 3 people in the house..)
By this time, the AST MGR came upstairs to see what is what. AST MGR called the company tech and was told to change out both the shutter driver and the jackshaft assemblies...along with the shutter.
Did the parts changeout and got the problem solved. I think that the shutter was defective and would not pinch down on the shaft very well.
Yes, I was flustered and embarrassed that of all the belt changes that I've done on these units that this was the first time I've experienced this kind of situation..and was politely recommended by the AST MGR to do belt changes before or after hours-not during operational hours.
*sigh* .. live and learn. - Monte
Posted by James Westbrook (Member # 3690) on 08-05-2010, 12:50 PM:
I'm guilty of wanting to perform some tasks on my regular shifts instead of coming in before the theater opens or after it closes. "There is 40 minutes between shows...that should be plenty of time." Then we discover...no...