Film-Tech Forum ARCHIVE: Stabilizing film on its way from a platter

This is topic Stabilizing film on its way from a platter in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Mark J. Marshall (Member # 1409) on 07-01-2003, 11:34 AM:

Sometimes when a splice works its way to the projector, it causes the film to jump off the first roller of the CAT 701 reader (the one all the way on the top right of the reader). It seems the film coming from the Strong platter is so lose, it just doesn't have enough tension to keep it in place.

I'm wondering if anyone else has ever seen something like this, and how you've dealt with it. All the rollers seem to be aligned pretty well, and I've tried moving things around, but the problem doesn't seem to want to go away. Is there a way to install a keeper roller on the 701 roller?

Thanks!

Posted by Brad Miller (Member # 2) on 07-01-2003, 01:18 PM:

Your roller on the top of the projector feeding into the Dolby penthouse is not aligned properly. Simple as that.

Posted by Mark J. Marshall (Member # 1409) on 07-01-2003, 02:09 PM:

I checked that again (checked it already several times, and tried several different postions) but sometimes it comes off and goes left and starts riding the edge of the 701 roller, and sometimes it comes off and goes right and comes off the roller completely. It really seems like an issue of lack of tension.

Posted by Brad Miller (Member # 2) on 07-01-2003, 02:28 PM:

What is the distance from the upper roller to the penthouse? Are you running the film with the least amount of twist? Often I see people running "soundtrack toward the screen" for no particular reason, which on many setups puts the film at a more than 90 degree twist which can make the film buckle and want to pop off of the track.

Posted by William Leland III (Member # 1400) on 07-01-2003, 02:46 PM:

We had the same problem with the film coming off that first roller. We finally put another roller above the first roller. I don't work at that theatre any more or I would show a pic. The roller was above the orginal roller and the film never slipped off. We did what Brad said but it didn't work.

Posted by Paul Salley (Member # 740) on 07-01-2003, 03:02 PM:

I too have seen this problem we worked and worked on the positions of the top roller, but the tension between platter and projector goes slack or bounces when a slice goes through. I have posted a couple of pics. We added a roller on the Cat701. This setup has worked for us.

Posted by Mark J. Marshall (Member # 1409) on 07-01-2003, 03:36 PM:

Brad,
There are some here who were trained by former GCC people who thread the soundtrack toward the audience. We are trying to break those habits, but I don't think its necessarily contributing much to our problem here. The upper feed arm roller is about 8" - 10" directly above the film cleaner roller. The "twist" is between the upper feed arm roller and the film cleaner roller.

Paul,
I noticed that you have the film coming from the film cleaner roller in the top photo, and you skip it in the bottom photo. Is that just to illustrate? Or do you always use the film cleaner roller, or how do you do that?

One of our problems is that we have all 3 digital heads mounted on removable brackets. Which complicates things a little when you want to lock down the permanent rollers. The SDDS readers have a similar problem, but the Dolbys are much more severe. I'd like to find a spot where the upper feed arm roller doesn't have to be readjusted all the time if you move the readers around. But no matter where I put it, I seem to have this problem. I'll look into adding that roller to see what happens. Thanks!

Posted by William Leland III (Member # 1400) on 07-01-2003, 06:15 PM:

Mark, what kind of film cleaner do u have. We placed ours on the platter tree. Our platters are Strongs with film cleaner brackets mounted already on them. We cleaned on the take up.

Posted by Brad Miller (Member # 2) on 07-01-2003, 06:28 PM:

Be careful about cleaning on the takeup side. If you clean with dry media you have very good odds of scratching the film with the heavy takeup tension.

Mark, can you take some pictures and upload them of your penthouses threaded?

Posted by Mark J. Marshall (Member # 1409) on 07-01-2003, 11:07 PM:

Yup. I'm away from the theater till Thursday night. I'll have them up as soon as I get back.

Posted by Wes Hughes (Member # 981) on 07-01-2003, 11:07 PM:

Dolby knows of this problem and will send you a new "first" roller for the 701 that has beveled flanges.