8mm Forum: Image jumping during projection

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Topic: Image jumping during projection - GAF1388

Sean Sexton
Junior
Posts: 16
From: SF Bay Area
Registered: Jan 2013

posted December 11, 2013 09:30 AM

I have a Sniper HD and I've noticed that the image during capture is jumping during capture. At first I thought it may just be the film that was causing the problem, but after opening up the back of the unit I can see that the pickup reel seems to not be running smoothly. It slows down slightly then jerks fast to keep up. During capture I held in place the pickup reel and the jumping stopped completely. I changed the belt thinking that could be the issue, but that has not resolved the problem. If anybody has suggestions that would be great! Thanks in advance. The projector used is GAF 1388

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Jim Schrader
Phenomenal Film Handler

Posts: 1628
From: Savage, MN, USA
Registered: Jun 2003

posted December 11, 2013 10:32 AM

Hello, since your unit plays both formats have you tried it with another format to see if it does the same thing? make sure your setting is for the type of film your running. try running the film to the take up reel without threading it through the machine if the take up reel works fine with out stopping maybe the film is not moving through the machine properly?

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jim schrader
"Let's see “do I have that title already?"

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Maurice Leakey
Film God

Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007

posted December 11, 2013 02:06 PM

Most take-up systems have a slipping clutch arrangement. Often these are lubricated for this very purpose. If the lubricant has dried up the take-up will keep snatching.
I should point out that this is a generalising comment because I have no knowledge of this particular US made projector.

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Maurice

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Jim Schrader
Phenomenal Film Handler

Posts: 1628
From: Savage, MN, USA
Registered: Jun 2003

posted December 11, 2013 04:34 PM

That sounds like a good place to start Maurice, however aren't most gaf's just plain old belt driven?

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jim schrader
"Let's see “do I have that title already?"

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Jim Schrader
Phenomenal Film Handler

Posts: 1628
From: Savage, MN, USA
Registered: Jun 2003

posted December 11, 2013 04:35 PM

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jim schrader
"Let's see “do I have that title already?"

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Sean Sexton
Junior
Posts: 16
From: SF Bay Area
Registered: Jan 2013

posted December 11, 2013 04:37 PM

Thanks for the feedback. Yes, the GAF is belt driven. I'm going to take a video images and post, b/c when I open up the back I can see that one of the cylinders (not sure the exact term) that helps turn the pickup reel is not turning smoothly, not sure why but I did replace the belt. I'll images shortly

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Janice Glesser
Film Goddess

Posts: 3468
From: Sunnyvale, CA USA
Registered: Sep 2011

posted December 11, 2013 05:27 PM

Yes...this is a belt driven projector. I've seen this behavior before. These Moviestuff telecine projectors have been modified. The original tires have been replaced by plastic spacers. If the rollers do not make good contact with the spacer...it can cause slippage or not turn at all. Conversely if it presses too hard on the roller this can jam it. Hard to know what is happeing without seeing it running.

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Janice

"I'm having a very good day!"
Richard Dreyfuss - Let It Ride (1989).

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Sean Sexton
Junior
Posts: 16
From: SF Bay Area
Registered: Jan 2013

posted December 11, 2013 06:28 PM

So I spoke with Roger from Moviestuff who was very helpful. One of the plastic rollers that turns the pickup reels has been worn over time, along with having a bunch of buildup. Roger suggest sanding the portion of the roller that touches pickup reel plastic spacer which I have done and it works much better now. Haven't had to call Moviestuff that often for help, but when I do they give awesome support. And thanks Janice for the info you gave me earlier today, along with everybody who replied to my thread. I really appreciate the feedback that all you give within this forum. Does anybody know of a good site/book that really dissects a projector and details what all the parts do and named? I feel like I'm describing wrong all the time b/c I don't know the exact name of parts.

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