Film-Tech Forum ARCHIVE: Century Projector Lower Gears

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Posted by Shane Hoffmann (Member # 1620) on 12-07-2003, 07:28 PM:

We have greased all of the gears one of our old Century projectors, but it persistently makes noise, mostly squeaking. I believe that the squeaking is from the lowest gear behind the soundhead, but I have lubed it over and over again. Is there anything else I should check or do?

Posted by Mark Gulbrandsen (Member # 72) on 12-07-2003, 08:56 PM:

Typically its the belt idler that squeeks. This tensions the belt that goes from the soundhead to the projector. If its an older Century machine then you'll probably find its a black phenolic idler, later machines have an alumnium and ball bearing idler. If you confirm that its the phenolic type then place a few drops of oil in behind so it can run down onto the shaft as well as a few drops from the front side of the idler. This usually cures the squeeking. If this problem returns frquently, then replace the phenolic idler with the later ball bearing version.

Also, if the take up reel belt drive gear is still in thereit might also be the squeeky contender. That gear is also located on the same arm casting that the tensioner mounts onto. A few drops of oil as on the idler will also take care of that. If its neither of the above you probably should get your service tech out ASAP as the problems may be bearing, or bushing related.

Mark @ CLACO

Posted by Paul G. Thompson (Member # 655) on 12-08-2003, 03:02 AM:

I agree with Mark. More than likely, the idler/tensioner is the problem. It is easy to verify. Use a plastic hose or a rubber hose such as a automotive vacuum hose and use it as a stethoscope. With this method, it is very easy to determine where the squeaking is coming from.

However, exercise caution so you won't foul the drive belt with the hose.

Posted by Jon Bartow (Member # 241) on 12-11-2003, 07:51 AM:

Just for kicks, grab the sprocket in the sound head and see if you can move it in and out or up and down. (Do this only when the machine is not running or course [Big Grin]

)

Posted by Mark Gulbrandsen (Member # 72) on 12-11-2003, 09:01 PM:

"Just for kicks, grab the sprocket in the sound head and see if you can move it in and out or up and down. (Do this only when the machine is not running or course"
_________________________________________________________________

I run into this all the time and carry a set of bushings in the van with me. You will find this problem with Centurys that have been running on Christie AW-3 platters for some years. The holdback on the payout heads causes the extra bushing wear. You'll also find the same problem with the Century JJ as well if the machine has run alot of 70mm film.

Mark @ CLACO

Posted by Shane Hoffmann (Member # 1620) on 12-11-2003, 09:16 PM:

That could be what our problem is. We have an AW-3 platter with that projector. We're having our tech come shortly, I'll have to have him check our other century/AW-3 setup as well.

Posted by Brad Miller (Member # 2) on 12-11-2003, 09:18 PM:

quote:
The holdback on the payout heads causes the extra bushing wear.

Well I've always said to remove those stupid springs, but some people insist they have to be in there. [Roll Eyes]

Anyway, what about a Century that has been running with an SDDS reader (particularly the 3000 model) for some time?

Posted by Michael Schaffer (Member # 1204) on 12-11-2003, 09:57 PM:

How can the payout holdback influence the sound head sprocket?

Posted by Mark Gulbrandsen (Member # 72) on 12-11-2003, 09:58 PM:

Brad,
If ya remove them you will sometimes experience DTS time code read problems....especially with Christie projectors, not to mention higher error rate on SRD!! If Christie would just make a delrin strap instead of the cheapo metal thing in there it wouldn't be a problem. Don't have any SDDS penthouses on Centurys in my sevice areas that I can think of. I'll just be happy to put the last SDDS system in the junk yard anyway....

Michael, The grease thats normally in there gets sticky after a few years and causes the center roller to have higher tension than when its new or freshly greased. A delrin spring band would eliminate having to have grease in there anyway. On the platters that need to have them on I re-grease them with SuperLube...it doesn't dry up or get gummy over the years. Other wise like Brad says...get rid of em.
Mark @ CLACO

Posted by Gordon McLeod (Member # 33) on 12-12-2003, 09:21 AM:

Often on older century styled soundheads there was an oilcup on the non operating side of the machine that provided oil to the soundhead sprocket shaft sleave and was usually forgotten in routine lubrication and then seizeing up wears and makes noise

Posted by Matt Zeiner (Member # 1914) on 12-12-2003, 05:56 PM:

I guess you are talking about the picture head upper holdback, Mark? 'Cause I also fail to see how the payout head is going to affect the soundhead holdback. Those springs should always be removed. I haven't experienced the issue with springless vs springged (huh?) payout heads and penthouse type readers. Not to say that the issue doesn't exist in some cases...

Posted by Mark Gulbrandsen (Member # 72) on 12-12-2003, 09:01 PM:

Matt......
The only issue is with P35GP machines, other Christie versions don't need the spring. Of course there have been too many issues with these machines to begin with! You definately get better results with the spring in there on everything else I leave em out.

Mark @ CLACO

Posted by Gordon McLeod (Member # 33) on 12-12-2003, 09:04 PM:

And I thought we were talking about century soundhead issue [Confused]

Posted by Mark Gulbrandsen (Member # 72) on 12-12-2003, 10:26 PM:

Yea.... I covered that by suggesting that he get the tech in to work on it if oiling the idler didn't help out. Suggesting that someone inexperienced and without replacement parts at hand dismantle the soundhead shaft and parts would not be wise.

Somehow we got onto discussing the upper busing wear caused by the darn tension spring in AW-3's. A valid point indeed...
Mark @ CLACO

Posted by Matt Zeiner (Member # 1914) on 12-13-2003, 11:44 AM:

OK gotcha. we are talking about a myriad of topics in this thread....We just got an account with a location of all busted up p35s. Lucky me. Mark - do you guys do Christie ultramittants? We do all of ours in-house for Cinemeccannica Century and Simplex, but I've heard that the ultramittants are not serviceable. Is this true?

Posted by Mark Gulbrandsen (Member # 72) on 12-13-2003, 11:16 PM:

Matt,
Yes, have done many of them in our shop. Christie(more likely LaVezzi) recently discontinued supplying the rebuild kits, or any parts at all. Perhaps its cause they've gone digital now... or perhaps they have LaVezzi working up a new replacement Digimittent [uhoh]

.

I know of other dealers that also did their own rebuilds and they now wait months for a repaired movement from Christie. Very sad indeed and another good reason not to by any P35's!

The most common failure I see out here in the dry climate is the outer cam ball bearing...hint hint... its an off the slelf ABEC 9 bearing as is the outer star bearing. Best to replace both of them if the cam bearing is shot. Ya can get em from Barden Bearing. The crapo made in Thailand bearing that comes in the Ultramittent also has crapo fibre covers on it that don't keep the crapo grease from drying out and moisture from getting in. I've seen outer cam bearings that were solid rust!! The inner bushings were both brass, possibly bronze, and the use of the inner ball bearings was discontinued a long time ago as they didn't last very long.
If you get a movement and it is still full of lube...hint hint.... LaVezzi Oil, then the star and cam are probably in good shape. Hint hint....If your fussy and like to do rebuilds the right way, then installing a new P360BB cam pin is a nice touch. Both seals in there are also off the shelf seals.

Ah, you inherited a pile of them ha??? I just left 4 of the first generation P35GP's a few days ago...real strange machine that has super critical belt tensioning. If they are too tight and you frame once too often the belt snaps! Oddly these 10 year old machines have the original movements in them and they run great. Tommrrow I'm off to another location that has 4 more P35GP's... the final version. I have my box load of belts, pulleys, bearings, and a few other parts plus my arbor press already loaded in the van. If you replace bearings in the pulleys, jack shaft bearings, or the shutter shaft bearings (R-4's and R-6's) buy the bearings that have the red rubber seals on them...they last ALOT longer in the black particle and gunk environment of a P35GP.
Other than that I'd reccomend taking your load of Christie projectors to the nearest scrap yard. Due to the alumnium pulleys they use in them they are actually require more technical maintainance than any other machine I've encountered.

I'm looking into making my own steel timming pulleys for the Christie. Using pre hobbed steel timming pulley bar stock they would be easy to make and the use of both steel pulleys and Kevlar belts might acutally make it nearly maintainance free for at least a few years.

I'm getting sick of working on Christies and continually feeding them parts [puke]

!!

Mark

Posted by Matt Zeiner (Member # 1914) on 12-15-2003, 08:45 AM:

Hey thanks, Mark. Much appreciated info. I sure wish I could get rid of them - not looking forward to the emergency repair calls, but I guess an account is an account in these dark days! I hear you are also the AAII man out there in SLC. Would like to speak with you about your experiences with VR upgrades if you have a minute. Thanks

mzeiner@netheatre.com

Posted by Mark Gulbrandsen (Member # 72) on 12-15-2003, 09:01 AM:

With good timming pulleys you should get a year out of a set of belts... don't go any longer than that though. The main thing is to get people at the locations to leave em alone and only you change belts, any worn pulleys, and set belt tension correctly. The last year has been quieter for P-35's but its taken several visits at each site and many, many new parts to get them there. Before this it was three times a year for belts, more at some locations, most of the problem was caused by the projectionists thinking they knew how to fix them.. they were changing the bad belts out and the rest of the machine was not getting the atention it needed.
Let me know whatever questions you might have with your Norelcos.

Mark