8mm Forum: Bell & Howell dual 8 (481A) shutter or dowser issue

This is topic Bell & Howell dual 8 (481A) shutter or dowser issue in forum 8mm Forum at 8mm Forum.

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Posted by Robert Zingarelli (Member # 4880) on July 06, 2017, 10:44 AM:

I am in the process of bringing this powerful little projector back to life, and have come across a stumbling block. I have changed the motor belt and cleaned all gears - but when I switch the lamp on, the "shutter" that is supposed to close and open - remains partially closed. I can move it manually with a paper clip, but it closes to about 80%. I have taken off the back - obviously, but this appears to be in the "film gate" area. Has anyone experienced this issue before. I am also planning on upgrading this to a halogen lamp which seems easy enough - but this shutter or dowser is a major concern.

Posted by Janice Glesser (Member # 2758) on July 06, 2017, 11:59 AM:

Hi Robert...Probably not a shutter issue. This sounds to me like the framer needs to be adjusted. This is the vertical knob located just above the main Forward/Reverse selector switch. This will adjust the masking in the gate. Often this needs to be adjusted when switching from Super 8mm to Std. 8mm films because of the frame size difference.

Posted by Robert Zingarelli (Member # 4880) on July 06, 2017, 03:43 PM:

Hi Janice, thank you ever so much for responding. I actually tried this last night and although it did not work (I did not go through the full right or left turn on the knob) plus it was while I was changing the motor belt. I sure hope you are right and I will try it tonight when I get home. Many thanks again!

Posted by Bryan Chernick (Member # 1998) on July 06, 2017, 06:56 PM:

These are service manuals for very similar models, they may be of some help.

B&H Model 459

B&H Models 456A, 456Z, 456X, 456XF and 456XP

Posted by Robert Zingarelli (Member # 4880) on July 06, 2017, 09:53 PM:

Awesome manuals Bryan - many thanks. I am searching within them now. Janice it was a great suggestion for the framer, but I knew it wouldn't be that simple unfortunately. This issue is a device that goes "left & right" within the frame behind the lens-and it is not returning to the "open" position. I can manually move it to the right with a paper clip, exposing the frame as it should be (but it goes back)? I thought it was the shutter or 'dowser" - (term found online), not sure what it is? The photo below will show the device, lens moved aside, looking within the frame. The 2nd photo shows what is projected.

Posted by Janice Glesser (Member # 2758) on July 06, 2017, 11:14 PM:

Ok Robert...the photo helped. You didn't mention the dot pattern and that's different than the framer masking blocking half the frame.

You should only see the circles when the "FWD-STILL-REV" lever is in the "Still" position. Make sure the lever is either all the way to the top for Forward or all the way to the bottom for Reverse. The circles are perforations in the metal plate that comes down to block the film aperture. It was designed to allow just enough light to still pass through to the film in order to have a "freeze frame" feature without the full lamp output burning a hole through the film.

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