This is topic Christie Platter Problem - AW3R in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Glenn Conatser (Member # 970) on 04-24-2002, 06:59 PM:
Hello Everyone,One of my platters is shaking bad when the speed arm is up to full speed. When things drop down to a slower speed the problem goes away. This shaking is ony happening in that speed zone. Typically when i get this kinda shaking its the drive wheel which has developed a flat spot but that isnt the case. Does anyone have any ideas what this might be.
Thanks,
Glenn
Posted by Darryl Spicer (Member # 711) on 04-24-2002, 07:33 PM:
Could possably be the center bearing rings that the decks sit on. THey may need to be greased or replaced.
Posted by Paul G. Thompson (Member # 655) on 04-24-2002, 07:41 PM:
The drive wheel could be in need of replacement. Check for rubber deposite chunks in the platter drive rim, and check the drive wheel itself. I'll almost bet that is where you will find your problem.
Posted by Darryl Spicer (Member # 711) on 04-24-2002, 07:43 PM:
That's what I would have thought too Paul, but he claims that the wheel is ok.
Posted by Glenn Conatser (Member # 970) on 04-24-2002, 07:51 PM:
Hi Paul and Daryl,The drive wheel is smooth with no flat spots at all. Could it be some thing in the motor itself ? Bodine motors are being used.
Thanks for the quick replies.
Glenn
Posted by Gordon McLeod (Member # 33) on 04-24-2002, 07:56 PM:
Well it would help to know what platter is involved
It is possible it is the centre bearing
Posted by Brad Miller (Member # 2) on 04-24-2002, 08:15 PM:
He is speaking of a Christie AW3R (he listed it in the subject header instead of the text).Glenn, I would swap drive wheels with another deck anyway to rule out the problem. I've seen wheels that I would've sworn were fine, but exchanging them with another deck proved that it was bad, as the problem followed the wheel.
I doubt it's the bearings. However I could buy the fact that the platter deck itself is damaged. All it takes is some bonehead splicing ON the platter, by punching down against the edge of the deck, instead of the proper procedure of raising the front end of the splicer off of the deck and squeezing the handle against the base. Once the deck cracks, you mine as well throw it away.
Posted by Gordon McLeod (Member # 33) on 04-24-2002, 09:02 PM:
Sorry didn't read the header
Some of the newer christie drives I found to be very soft and left a deposit that made the action jerky
Posted by Glenn Conatser (Member # 970) on 04-24-2002, 09:18 PM:
Well it looks like it was the drive wheel after all. The funny thing is im looking at it and see nothing to cause the vibration. I also visually inspected the platter and noticed no cracks or damage.Thanks again for the help.
Glenn
Posted by Will Kutler (Member # 770) on 04-24-2002, 10:05 PM:
A few years ago Christie had a problem with defectivly manufactured drive wheels that developed flat spots and were out of round. Christie promptly recognized and offered replacements which I believe were free? I do not know what Christies current policy is, so ask Bevan...
Posted by Scott Norwood (Member # 30) on 04-24-2002, 10:11 PM:
On the topic of Christie platter issues: what would cause a drive motor to make squeaking noises? I don't see how the drive "puck" would cause this, but I can't think of anything else that might. I am assuming that the motors are not supposed to be oiled; is this correct?Also: is there some sort of trick to re-mounting a motor after removing it to change the drive "puck"? For some reason, I always seem to have difficulty compressing the spring enough to get the motor in place....
Posted by Will Kutler (Member # 770) on 04-24-2002, 10:27 PM:
Maybe the motor bearings are bad? According to Christie instructions, the brushes should be removed every 6 months I believe and the carbon blown out and the brush length measured to ensure they are over min length specs. Warning is given that if this is preventive/routine maintenance is not performed you may risk the motor shorting out from excessive carbon dust. However, I have known a few techs who say that they have never done this and have never had a problem. I do think that the Bodine motors are iffy. The stator magnet is a cast composite and not stacked metal. On one occasion I went to blow out a motor per the above mentioned maintenance. Unbeknownst to me, the magnet was flaking and cracking and when went to blow out the motor, chips got stuck between the stator and rotor hanging up the motor. I did a quick disassembly of the motor, cleaned it out so that I could temporarily get it back in service. I then promptly called Bevan to let him know what had happened. Needless to say he was not too happy that I disassembled the motor because I could have voided a warranty. I did make the suggestion to several manufacturers that brushless can motors be used on platters, but my sugestion has been veteoed because of how expensive these motors are. The Christie lamphouse exhaust fan motors do require oiling I believe every 6 months. To my knowledge, the platter motors do not require oil.I too would like to know about a single person method of removing and replacing these motors. In my experience, 4 hands are better than 2!
Posted by Brad Miller (Member # 2) on 04-24-2002, 10:50 PM:
Don't remove the motor. Take a screwdriver and prop the motor away from the edge of the deck, then just remove the deck. This is MUCH easier than removing the motor.
Posted by Darryl Spicer (Member # 711) on 04-24-2002, 10:59 PM:
Yes it is much easier to take that deck off than it is to remove the moter. But you still will need four hands to lift it off.I know some of you may remember when christie changed there platter motors to the small green ones. The ones that would just run cuntinuously when they would go bad. Pieces of crap. Are there still any of this still in use or have they been switched back to the black motors.
Posted by Gracia L. Babbidge (Member # 582) on 04-24-2002, 11:01 PM:
Scott - what I've found when I had to re-mount a motor, was that the trick is have someone else help you!
Just get the spring compressed to where you want it, then have your helper hold it there.
Piece of cake. 
Posted by Glenn Conatser (Member # 970) on 04-24-2002, 11:16 PM:
Im still running some of those green motors and had the problem mentioned above where the motor keeps running. However that was changed to one of the Bodine motors. No problems since then and the great thing about the Bodine motors is they can be repaired where as the Christie ones couldnt be fixed. Cheers,
Glenn
Posted by Michael Rourke (Member # 1142) on 04-24-2002, 11:31 PM:
I can lift decks off their axle without help...the secret is the chin.I had some of those defective drive wheels and they just come apart like an old eraser, very messy. The new drive wheels are much harder and when the deck starts to spin they squeal like little piggies...until they get broken in.
I blow the carbon dust out of the platter motors every year, at six months there isn't any dust to speak of. Not doing this at all wouldn't make the deck shake the only problem that comes from not blowing out the motors would be squeaky motors.
Glen: Make sure you grease your axle bearings every year too for smooth platter operation; and whenever you aren't using a deck for an extended amount of time, prop the motor off the platter arm or you'll give the drive wheel flat spots. They're 40 bucks apiece!!!!
Posted by Darryl Spicer (Member # 711) on 04-25-2002, 08:57 AM:
A good practice to do to prevent the flat spots from occuring due to not using the platter. use all three platters. If the print is on the top platter run the first show to the middle. Then run the next show to the bottom. Then run the next show to the top. Just keep repeating the rotation.
Posted by Paul G. Thompson (Member # 655) on 04-25-2002, 01:51 PM:
Darryl, you have a good point. Maybe Christie could make a retrofit kit to release the tension any given platter is not used frequently. Something like Strong International did on their A-3's, and Xetron did on their XNR series.
Posted by Will Kutler (Member # 770) on 04-25-2002, 06:09 PM:
The worst thing for ANY piece of complex mechanical equipment is to let it sit for extended periods without use. Make it your business to use that extra platter deck at least once a week....
Posted by David Whitbeck (Member # 894) on 04-25-2002, 06:42 PM:
Since you're all on the subject of the AW3R, I've got a problem that just popped up myself. Today I noticed that when the take up arm was pulled all the way over to the motor, the motor kept creeping. This didn't really make my leader too happy... Anyway, we just got these put in so I decided to ask you guys before I dig into them. What do I need to adjust?
Posted by Paul G. Thompson (Member # 655) on 04-25-2002, 07:28 PM:
David, that is just an adjustment. Check your manual on how to make that adjustment. It could be a mechanical adjustment of the light shutter in the module to a mis-adjusted control module. More than likely, it is a control module adjustment. Re-time the whole system IAW the manual, and you should be just fine.
If you didn't get a manual with your machines, there is a manual you can download in the FT Manuals section.
Posted by David Whitbeck (Member # 894) on 04-25-2002, 08:22 PM:
Yeah, I looked in the manual, but it didn't really say anything about my problem so I really just wanted to confirm that it was the control module before I screwed with it. Thanks Paul.
Posted by Brad Miller (Member # 2) on 04-25-2002, 08:27 PM:
Odds are your timing has drifted. The quick fix is to open up the side column of the platter tree and adjust the LO pot just a touch counter-clockwise until the creeping stops. That'll keep you on screen, but you need to re-time that platter a.s.a.p.
Posted by Gordon McLeod (Member # 33) on 04-25-2002, 08:29 PM:
Since they have just been put in it is possible that the arm has gotten shifted on the control for the take up not creating the correct "0" point
Posted by Michael Rourke (Member # 1142) on 04-25-2002, 09:20 PM:
David, if the problem still occurs after re-timing leave the brain out of the take up deck, that might be giving mixed signals to the control sensor assembly.
Posted by David Whitbeck (Member # 894) on 04-25-2002, 10:07 PM:
I set the brain arm at 20 and turned down the Low pot until the platter was just creeping, this is what the techs said to do and the same with the manual, it seems to be OK now. Now that I've done this and it's working fine, will I really need to retime the High speed?
Posted by David Whitbeck (Member # 894) on 04-25-2002, 10:08 PM:
Oh, and we have only one brain per set of platters so the brain isn't interfering with the signal any. Just so you know...