Film-Tech Forum ARCHIVE: Simplex XL screen jitter

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Posted by David E. Nedrow (Member # 4981) on 03-13-2011, 09:04 PM:

I thought I'd start a new thread up, since I've resolved the ghosting issues, yet the jitter remains.

There is a slight, but noticeable, up and down jitter on the screen. This is not ghosting. It's really distracting on scrolling end credits, where the credits will jump up, and then back, below where they should have ended up had everything been going smoothly.

As I was fixing an earlier ghosting problem, I noticed that the shutter shaft moves back and forth, perhaps 1/8 of an inch, in a rhythmic pattern. It can be seen on the front end of the shaft (non-operator side) and on the back end, via the the shutter itself.

Comparing to our #2 machine, I can see that #2 's shutter shaft is steady, with no lateral movement.

Thoughts on what might be allowing the movement? Should I loosen the shutter, then carefully push it further on the shaft, while holding in the front of the shaft on the the non-operator side?

David

Posted by Louis Bornwasser (Member # 3063) on 03-14-2011, 09:25 AM:

Movement of the shutter shaft could be one of two things:

1. Simply the shutter assembly needing rebuilding/adjustment internally.

2. Anything that causes a binding or a hesitation to any part of the gear chain. For example: Really stiff gate tension will inhibit the normal operation of the intermittent when it pulls down. Could be anything else,too. Common problem with XL's. Louis

Posted by Tony Bandiera Jr (Member # 2365) on 03-21-2011, 07:13 PM:

David, if the shutter shaft is moving back and forth the drive assembly needs to be rebuilt.

Or the shutter blade is out of balance.