Author
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Topic: Cat 701 hissing noise?
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Paul G. Thompson
The Weenie Man
![](http://www.film-tech.com/cgi-bin/paulpics.cgi)
Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000
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posted 08-19-2002 02:51 PM
Josh, get a hunk of plastic tubing about 1/2 inch or 3/8 inch inner diameter from your hardware store and use it as a stethoscope to locate the noise.If it is just sitting there and hissing, check and see what your cat is. ![](http://www.film-tech.com/ubb/biggrin.gif) You didn't say if you were running film through it or not when it is hissing, but I presume you are. It could be something mechanical such as the bearings in the little pad rollers or the flywheel dragging on something. More than likely, it is from the pad rollers or the guide rollers themselves. It could also be noise being emitted from the LED power supply for one reason or another.
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Jeff Skallan
Film Handler
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Posts: 65
From: Littleton, CO, USA
Registered: May 2001
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posted 08-20-2002 04:05 AM
Josh,I've heard a few CAT 700s buzz and hiss. In my experience this is usually caused by a loose or misaligned pad roller in the penthouse. Also on occasion I've found that using the tension spring inside the Christie platter brain will slightly increase the hissing noise, but doesn't really adversely affect the film. (I actually like to leave it in place rather than removing it while threading though the CAT 700.) I've experimented with removing the brain holdback spring to find the hissing noise quiet down, but the error rating from our DA-20 went up by 3 points! Interesting enough, while manually holding the film edges with my fingers between the platter and projector with an increased amount of tension in this same instance, I've been able to produce error ratings of "0" on the DA-20. Unless the hiss noise is unusually intense, I have to agree with Mike and Paul that it may be quite normal to hear a bit of it from various film stocks. My 2 cents worth... -- Jeff
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