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Does anyone know how to adjust the film feeding claw? I made a post a few weeks ago, and still having issues. Thanks.
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Whoa, wait a minute.
Judging from your video on Reddit, that seems a bit like SUPER8 film on REGULAR8 projector?
Please verify the film format first...
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Ahhhhhhhhhhhhhhhh….That is probably it.
Thank you!Comment
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Nantawat, I have had a similar experience as Rick had, but with the correct 8mm film. After I figured out how to change the belt my DeJur 1000 did not feed properly. The fork mechanism behind the lens moves well, but it is stopping the frames from advancing. This causes the loop above the lens to grow continually, so the bottom uptake reel keeps breaking the film simply by pulling on film that can't advance. My guess is that the cam controlling the fork was not timed properly when I put the parts back together after changing the belt. Do you no how to position the cam vs the main gear during reassembly? I'm guessing that I have it 90 degrees out of phase. Thank you.Comment
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These pictures highlight the fork cam and main drive gear inside my DeJur 1000. As I mentioned in my first post my DeJur 1000 projector seems to have a timing problem after I replaced the belt. Please see my previous post. The two rivets on the fork cam probably need to line up in a specific position with the shutter prop position key knob on the main (reddish) gear. I have determined that the fork cam rivets do align in a straight line with the key in what I call the "A" position at the beginning of the cam's idle position. The cam will move at idle about 90 degrees to what I call the "B" position before the fork starts to move. If you look at the two pictures I posted you will see what I mean about the rivet positions at the beginning and end of the cam's idle positions. I don't know if there is any option to align the cam and the reddish drive gear. I may not have put the gear back in its exact position after I replaced the belt. Thank you.
Position A
Position B
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I'd love to. Unfortunately for only God known reason those pics didn't show up
so I'll have to make some general assumptions, and not model-specific.
In general there are 2 main components in every projectors to transport the film (please disregard the sprocketless projector design at the moment
).
The first is the claw movement used to pull the film through the film gate by grabbing the sprocket hole, pull it down, then retract. If working properly it should pull each new film frames to exactly the same position, every time.
The second component is the sprocket wheel(s) - usually 2 of them. The first one is used to pull the film at steady speed from the supply reel, and feed in into the film gate. The second one is to pay out the film to the takeup reel at exactly the same speed.
Both component must run at the same speed in order to transport the film through the projector. If there's any slippage between the two the film will be damaged of course. I suggest to thread the film, then slowly rotate the mechanism by hand to inspect the action of each component. Are they working in tandem, and normally as they should?Comment
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Dale's pictures in post #5 are now viewable.Comment
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My DeJur 1000 has a three-winged shutter disk (I don't know what it's formal name is). The back side of the shutter disk acts as a cam and pushes the fork forward into the film's perforations and then allows the fork to retract with every rotation. The top of the shutter disk has a semi-circular raised area that is a mirror image of the cam area on the back side so you can see the section that pushes the fork when the whole thing is assembled. I don't think there is any way to change how the upper and lower sprockets synchronize with each other. The DeJur is built with metal gears and chains that move the sprockets. There is no way for them to slip that I can see from how they were assembled the factory. I am confident that the position of the horizonal cam action on the backside of the shutter disk relative to the cam that moves the fork vertically is critical to advancing the film properly. Right now my trial-and-error positioning of the shutter disk has only resulted in the fork holding the film in place rather than advancing it. The result is that the take-up reel repeatedly tears the film in half.Comment
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Ah, I GOT IT.
From the (now viewable) pictures & additional description I think I can now figure out how it works, sort of.
The upper gear where the shutter blade was attached to would contain a cam for controlling the claw's IN-OUT position. The cam on the lower gear will control the claw's UP-DOWN position. I guess that the gear ratio between the two would likely to be 3:1 or so. It means that the up-down cam will have 3 revolutions, while the in-out cam will have only 1 revolution.
So only one out of 3 rev. that the claw will actually move forward, make contact, and advance the film. The other 2 rev. it would be retracted and running idle.
As you can see that the TIMING between these 2 gears are VERY CRITICAL. The claw tip must protrude out only at the exact timing in the cycle - not too soon and not too late. Otherwise it will fail to advance the film and cause damages like this.
(Imagine tuning a car's ignition timing - roughly the same thing.)
So yes, a disassembly, and re-timing the gear should resolve this issue.
PS I also did had an issue about missing pics in my previous post yesterday also. Not sure what caused that?Comment
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