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This topic comprises 2 pages: 1 2
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Author
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Topic: Question about scratches
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Ken Lackner
Phenomenal Film Handler
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Posts: 1907
From: Atlanta, GA, USA
Registered: Sep 2001
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posted 03-11-2009 06:45 PM
I'm sure many others will chime in here with suggestions for both projectors, but one thing I can think of for #16 is your failsafe. If you have the type of failsafe that uses mechanical drop arms, and the film rides on top of bearings, those bearings can be a source of trouble. Although they should only touch the edges of the film outside the picture and soundtrack (except, of course, for the SDDS track), I have seen some where the edge of the bearing rides just inside the image area of the film. Xetron, Big Sky, and "Christie" (manufactured by Speco) failsafes use this type of design. I believe Kelmar does, too, but I'm not 100 percent on that one.
Please list your entire setup, as it will help greatly in troubleshooting. The problem very well may not be in the projector head.
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Gordon Ford
Film Handler
Posts: 2
From: Wolverhampton West Midlands
Registered: Oct 2003
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posted 03-16-2009 04:17 PM
Ok lets look at average film path, now where does the film actually weave like that? not usually on rollers, but in between rollers maybe. So lok at the film path when lacing up and see if anything is close to film when laced up, anything very close to film plane? Look at feed off unit, does film "relax" or drop when not under tension when running? gate area is unlikely as film is under tension and would be stable running, unless you have excessive wear somewhere , but that is likely to show on screen. Without expert knowledge of the equipment you are using, the best advice is lace up a small a trailer and LOOK at all ther film path where weave could occur. The scratches are black so that will be on the base, the emulsion scratches are white or coloured, depending how deep they go and which colour layers are removed. As to the green dots, the most likely cause is on a constant speed sprocket, either has been laced incorrectly, also if this is the case you will find that the scratches could be caused by the one side teeth of the constant speed sprocket,( this would probably be on the emulsion side) therefore being done at the same time as the wavy scratches? or has poor quality machining inside the teeth leaving slightly raised edges, is there a new sprocket? Best of luck in your investigations sherlock LOL Regards Gordon
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