This is topic Motiograph AA help needed in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Mike Heenan (Member # 392) on 06-30-2001, 12:05 AM:
Hi there, just trying to get the hang of this motio. AA I just got. I have a test reel of film which Ive been running so far without problems, but lately with a few reels of trailers and such, the upper loop in the projector head snags every now and then, and the film catches into the gate. Ive checked the film that Ive run, and there's no splices or broken sprockets in the area where the snag occured. I do a two finger sized loop on the upper loop. What's weird is that a few of the reels snagged roughly at the same spot, running fine for the majority of the reel, then doing that within the last minute or two. Any suggestions? Thanks.
Posted by Jerry Chase (Member # 660) on 06-30-2001, 12:31 AM:
Too much hold back tension.
Posted by Mike Heenan (Member # 392) on 06-30-2001, 01:36 AM:
What's a good setting for the tension bar? I think mines at the top. Thanks.
Posted by John Pytlak (Member # 331) on 06-30-2001, 07:30 AM:
Generally, use the lowest possible level of holdback tension that still produces a steady image with good focus uniformity.------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
Posted by Ken Layton (Member # 133) on 06-30-2001, 09:34 AM:
The gate has a 3 step tension adjust: Low, Med, High. Run at Medium or low. Are sprocket teeth hooked or worn?
Posted by Brad Miller (Member # 2) on 06-30-2001, 12:40 PM:
Mike, are you losing your upper loop? The way I read that post, that is what you are trying to express. If so, then I would check the upper sprocket's pad roller and make sure it isn't too loose. (Can 3 layers of film fit on the sprocket with the pad roller closed and still allow the pad roller to spin freely? If so there's your problem.) Also, if you were inquiring about the supply reel's backtension, set it as low as possible, but not so low that you have a bounce to the film coming off of the reel.
Posted by Gordon McLeod (Member # 33) on 06-30-2001, 01:52 PM:
The rule of thumb is padrollers are supposed to be 2 thickness of film
Posted by Mike Heenan (Member # 392) on 06-30-2001, 02:42 PM:
Ok thanks guys, Ill do the tension bar as suggested, and report back. Brad, that's exactly what I was trying to say, Im losing the upper loop, and Im sure if I didnt catch it in time, it wouldve snapped the film. I will try the thing on the pad roller and see what happens there.
Posted by Mike Heenan (Member # 392) on 06-30-2001, 08:32 PM:
Hi all, it appears your advice worked, thanks! I just ran a 6000' reel, no snaps or loss of upper loop. The tension rod was roughly in the middle. And I also loosened the tension on the supply reel. Ill fiddle around with it more to see if I can determine what was the problem, if one thing was causing it, etc. Thanks again!
Posted by Mike Heenan (Member # 392) on 07-21-2001, 01:11 AM:
After many tests, snaps, and such, I think I finally discovered the problems. One of the problems was a loose and slightly misaligned pad roller on the lowest sprocket in the soundhead, so I switched it from another one in my old soundhead, and it cured it. Then, I discovered that the top pad roller (thanks Brad!) in the projectorhead was loose, and spun around, so I tightened it, and appears to work now. I just wonder how this stuff got loose in the first place!