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Author Topic: Infuriating scratches. Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 11-30-2008 08:15 PM                     quote: James Waite Since that loop has no defined size we all make it different sizes Okey, I can also see what's happening: You have a 5star head with that "shock absorber" roller to the left of the holdback sprocket. There is actually a defined size that is required for this soundhead: the film needs to be pulled full tight across the holdback sprocket where the 'shock absorber' roller (called a 'snubbing' roller) is fully pulled forward. Then, you back the film over the sprocket one sprockethole, then close the pad roller over that sprocket. This will still allow the 'shocking' action of the snub roller, but keeps the film tight enough to not allow any slack of the film during startup and operation. -Monte  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 11-30-2008 10:22 PM                     Yes, most make the isolation loop too large. It need not be large at all...it should look like a ")" and that is it. It isolates the film from the outside world...which with a platter, isn't going to be too much other than what the take-up elevator might inject. However, it is a good idea to change the pad roller anyway. The flanges are likely chamfered now. MNR-221s are good though a better roller to use is the SOR4-22 as it is precision ground metal and the inside flanges are under-cut slightly to prevent scratching. Steve [ 12-01-2008, 05:50 AM: Message edited by: Steve Guttag ]  |  IP: Logged Eric Robinson Jedi Master Film Handler Posts: 538 From: Santa Rosa, CA Registered: Jan 2005 posted 12-01-2008 09:34 AM                     It also sounds like the pad roller arm closing distance may be off since the film can skip sprocket teeth when a splice goes through. If you do work on the pad roller arm, you need to make a few adjustments. Be aware that one of the pad roller shafts is eccentric where it mounts to the pad roller arm. If you loosen the locking screw which holds the pad roller shafts you will notice that one of the pad roller arm shafts does change its relative position with respect to the sprocket when rotated and the other does not. Note: First replace your pad rollers and ensure that they spin freely on the pad roller arm shafts. Pad roller arm adjustment steps: 1) Wrap two pieces of film around the sprocket. Hold onto the ends of the film so that they are wrapping tightly around the sprocket. (in the same position they would be in during normal film play) 2) Rotate the eccentric pad roller farthest away from sprocket. 3) Close the pad roller. 4) Turn the non-eccentric pad roller by hand. 5) Adjust the pad roller arm closing distance stop screw so that the non-eccentric pad roller gives a very slight resistance. 6) Remove the two pieces of film and put in one piece of film. 7) Turn the non-eccentric pad roller by hand. 8) The pad roller should turn freely with no resistance. Repeat steps 5 through 8 until you get the proper result. Then, adjust the eccentric pad roller distance to the sprocket so that it has the same behavior with one and two film thicknesses.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 12-01-2008 01:40 PM                     quote: Eric Robinson Wrap two pieces of film around the sprocket. ...but, folding a length of film over the sprocket, then close the pad roller over this fold to make the two layers is tons easier to do .... But, one needs to adjust the entire pad roller arm assembly first with the stop screw to get the two film thickness with the rear pad roller since that roller is not on a eccentric shaft as the front shaft is. Then, after the rear adjustment is made, then one does the front eccentric adjustment for the two film thickness between sprocket and roller..if you want to make it an offical adjustment for the record books. ,,and this goes for all pad roller assemblies on a Simplex .. and practically with all two pad roller arm projectors.. -Monte  |  IP: Logged Eric Robinson Jedi Master Film Handler Posts: 538 From: Santa Rosa, CA Registered: Jan 2005 posted 12-01-2008 02:04 PM                     quote: Monte L Fullmer ...but, folding a length of film over the sprocket, then close the pad roller over this fold to make the two layers is tons easier to do .... These techniques are hard to explain in writing, for example, I don't understand what you are saying above. Nonetheless the information has been made available and the reader could certainly gain from it and he/she could ask for clarification if needed.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 12-01-2008 02:56 PM                     quote: Eric Robinson for example, I don't understand what you are saying above. We old school techs know this one since we were raised with this procedure..but sorry, didn't know I confused you. To make it simple then: 1-Take a piece of film and fold it in half. 2-Lay it across the sprocket with the teeth coming through. 3-Hold the fold down over the sprocket and close the pad roller over this folded film and the pad roller should still spin freely. Try this one out for size. - Monte  |  IP: Logged

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