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Bell & Howell 483A runs fine backwards but not forwards

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  • Bell & Howell 483A runs fine backwards but not forwards

    I've written about my restoration of this projector on two previous occasions:

    Bell & Howell 483A Tire Replacement


    Bell & Howell 483A Runs Too Slowly - Can't Fix - Recommended Repair Shops?

    I successfully replaced the tires.

    Then, for the speed issue, I changed the tire friction by moving the black adjustment plate while the projector was in "neutral" until the tire just started touching the inside of the shutter wheel. I then backed off a fraction and tightened the two screws. It was this adjustment which caused the speed problem I wrote about in my second post above. I suspect that the diameter of the new tire was slightly smaller than the original.

    I then did a complete cleaning and lubrication. It now runs very quietly and smoothly.

    However, there is one problem. When I run the film forward, the picture jumps on each frame. The loop looks fine, and if I turn off the projector and manually advance the film, I can see the loop bob up and down as the pulldown claw grabs the film.

    A possible clue to the problem is that if I turn the framing adjustment all the way to one extreme, the picture settles down and looks normal.

    I have measured and adjusted the claw protrusion, and my calipers show that it is set exactly at the nominal spec of 0.040."

    The framing control simply changes the "advance/retard" of the claw relative to the gears, so I am not sure why the claw isn't advancing the film except at one extreme of that control. Visually, it looks like the claw isn't engaging, even though when manually advanced I can see the claw's work by looking at the loop.

    If anyone has some suggestions, I'd sure like to hear them. Everything else about this machine is in great shape now, and I feel like I am just one adjustment away from having it running smoothly again.

  • #2
    I just found an old post from someone with the exact same problem. He never got a response.

    Help w/ Bell & Howell 461 A

    Picked up this projector at the thrift store in non-working condition, opened it up, cleaned it inside and out, new belt, lubed up the gears, etc. Everything looks to be operating correctly, but when running the film through forward, it is all jumpy and jittery. It will run it in reverse as smooth as silk.
    What am I missing? Hopefully something simple?