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Topic: Christie Platter Problem - AW3R

Glenn Conatser
Film Handler

Posts: 73
From: Northern California
Registered: Aug 2001

posted 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

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Darryl Spicer
Film God

Posts: 3250
From: Lexington, KY, USA
Registered: Dec 2000

posted 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.

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 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.

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Darryl Spicer
Film God

Posts: 3250
From: Lexington, KY, USA
Registered: Dec 2000

posted 04-24-2002 07:43 PM

That's what I would have thought too Paul, but he claims that the wheel is ok.

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Glenn Conatser
Film Handler

Posts: 73
From: Northern California
Registered: Aug 2001

posted 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

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 04-24-2002 07:56 PM

Well it would help to know what platter is involved
It is possible it is the centre bearing

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Brad Miller
Administrator

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

posted 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.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 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

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Glenn Conatser
Film Handler

Posts: 73
From: Northern California
Registered: Aug 2001

posted 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

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Will Kutler
Phenomenal Film Handler

Posts: 1506
From: Tucson, AZ, USA
Registered: Feb 2001

posted 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...

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

posted 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....

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Will Kutler
Phenomenal Film Handler

Posts: 1506
From: Tucson, AZ, USA
Registered: Feb 2001

posted 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!

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Brad Miller
Administrator

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

posted 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.

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Darryl Spicer
Film God

Posts: 3250
From: Lexington, KY, USA
Registered: Dec 2000

posted 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.

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Gracia L. Babbidge
Jedi Master Film Handler

Posts: 709
From: Bowdoin, Maine
Registered: Aug 2000

posted 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.

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