Film-Tech Forum ARCHIVE: Strange Maltese sound

This is topic Strange Maltese sound in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Antonio Marcheselli (Member # 373) on 06-20-2002, 12:46 PM:

Hi everyone

Yesterday I was cleaning deeply one of our projector. I notice that the maltese movement makes a strange sound while running.

It is a "click" when the maltese sprocket starts moving. It doesn't appears if I move the motor knob counterclockwise and it is not regular (not like click-click-click-click-click but click---click-click-----click-click--click).

No problem with the picture on the screen. Is it something to worry about?

Bye
Antonio

Posted by Richard Fowler (Member # 893) on 06-20-2002, 03:55 PM:

Other sources of random clicks are the gears in the shutter box and the idler rollers for the timing belt aroound the intermittent and shutter box.
Richard Fowler
TVP-Theatre & Video Products Inc

Posted by Paul G. Thompson (Member # 655) on 06-20-2002, 05:54 PM:

Is the shutter beating on something?

Posted by Antonio Marcheselli (Member # 373) on 06-20-2002, 06:51 PM:

I forgot to say that I also tried the shutter without have the belts pass through maltese movement and there were no strange sound. That clicks are just in the same moment when the sprocket start to move.

Antonio

Posted by Paul G. Thompson (Member # 655) on 06-20-2002, 07:15 PM:

Check the indexing of the star and cam. They may be wearing out. Also check the intermittant sprocket for lateral movement.

Posted by William Phillips (Member # 1162) on 06-21-2002, 12:11 PM:

I had a similar sound on my Vic 5 a few months ago. The picture was good, so the first thing i did was to replace the belt idlers just to make sure it wasnt them, the noise was still there so the tech came out to put a new led in for me so I got him to take a look while he was here. He had a listen to it and straight away he said that the messing between the cam and cross was out a bit. He redid it but did say that they will run quite happily like that for years or their whole life and not do anything nasty. He also said the time to worry is when the picture looks strange or the cross box stops turning.

Posted by John Pytlak (Member # 331) on 06-21-2002, 01:00 PM:

A very useful diagnostic tool is a stethoscope. Very useful for isolating the source of an unusual sound. Many pharmacies sell simple "blood pressure monitor" kits that include a stethoscope for under $20 US Dollars.
CVS Stethoscope

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by Don Sneed (Member # 955) on 06-21-2002, 02:44 PM:

Hey John P. that is a great idea, I never thought of that !!! An old projectionist (now pass away) once showed me how to check for a noisey bearing, use a long screwdriver, put the flat blade of the screwdriver on a bearing (being careful not to get off the bearing & into the gears)or use the bearing housing, put your ear to the handle of the screwdriver & listen, a good bearing will be smooth sounding or very close to it, a bad bearing will have a rough sound or noisey...you will know when you come accross a bad bearing....I have use this to find many bad bearings in all makes of projectors...crude way of checking bearings...but it "works"... !!

Posted by Paul G. Thompson (Member # 655) on 06-21-2002, 03:07 PM:

A hunk of garden hose makes a good stethoscope. Used them many times...

Shove one end in your ear, and point the other end to what you want to hear.

Posted by John Pytlak (Member # 331) on 06-21-2002, 03:08 PM:

But a real stethoscope makes you look like a doctor! Especially if you wear a white lab coat.

DOP = Director of Photography

DOP = Doctor of Projection

Posted by Jerry Chase (Member # 660) on 06-21-2002, 04:50 PM:

"A hunk of garden hose makes a good stethoscope. Used them many times...
Shove one end in your ear, and point the other end to what you want to hear. "

A friendly word of advice, Paul. Never, ever, listen to farts with this setup. You'll blow your brains out.

Come to think of it, I wonder if this is what happened to the people that seem to have for brains?

Your mother had it right. Never stick anything in your ear that is smaller than your elbow. Using a hose or tube that isn't capped might not be the best idea.

Posted by Jonathan Worthing (Member # 803) on 07-01-2002, 05:46 AM:

Which projector is it

I have had the same sort of problem with a Westar intermittent.

The reason it was doing it was the locator which gives you the amount of turn you give the unit when putting the unit back. The cam becomes strained incorrectly with the cross.

Also I have seen the wrong screw put back in the fly wheel making it uneven on rotation.
I would suppose it is not that one, as the customer that did that could not find the screw he had taken out so he put one that fitted through with a locking nut on the other side.

Posted by Gordon McLeod (Member # 33) on 07-02-2002, 04:51 PM:

I have a mechanics stethascope that is a rod is connected to the standard earpieces

Posted by Ray Derrick (Member # 1001) on 07-03-2002, 05:52 AM:

Sennheiser (I think it was them) used to (and probably still do) make a diagnostic microphone for finding the source of mechanical noises primarily in motor car engines. It is a tiny electret mic at the end of a long probe, but the beauty of the system is the little preamp box that lets you plug in a set of headphones. The little box has switchable filters to enable you just to hear the noises in certain frequency bands. It would be very handy for projector maintenance. Some of you guys could probably make one of these up yourself.

------------------
Ray Derrick
President/Chief Engineer
Panalogic Corporation Sydney, Australia
Phone: 61 (0)2 9894 6655 Fax: 61 (0)2 9894 6935