> If you are interested to see more, follow this link where I demonstrate the > problem (password is 'loop').
There are probably folks here who know projectors better than I do, but I'll offer my best guess fwiw in case you don't get a more expert response… I suspect your Athena needs some fairly serious service. At the beginning of the video, there's no lower loop and it takes several pulls of the loop former to get the lower pop to take. This would suggest the claw isn't engaging the sprocket holes reliably in the gate, failing to push the film down, with the friction drag in the gate causing the upper loop to grow until the lower loop is tight. When you stop the projector the first time the lower loop holds, then loses a frame when you throw the lever back to 'play'. I assume this happens because the claw isn't engaging a sprocket hole in 'stop' mode as it should. It doesn't push the film down until after the sprocket wheels begin turning, which is wrong. The second time you move the lever to 'stop' the lower loop loses a frame both on the stop, and then again on the restart to play. So, again that seems like a problem with the claw in the gate, and the lack of a loss on the first 'stop' was just luck. I suppose there could be a problem with the pressure plate not holding the film correctly in the gate, or the film stock used in the test just has 'issues'. Did you try it with different samples/types of film stock? But I'm thinking it's the claw. The projector, like most cameras, is supposed to complete a pull-down cycle before coming to a abrupt stop, and rest with a frame directly in front of the aperture in the gate. This is a mechanical thing, engineered into the stop mechanism. So, for example, if you turn the projector off and on with an electrical switch in-line with the power cord, it won't stop with a frame in that stop position, claw engaged, just any old spot in the cycle and it will slow down first for a second before the inertia runs out. Then, if you restart by turning that inline switch back on, it will miss at least one frame in the gate as it speeds back up and the claw finds a hole to engage. What your Athena is doing looks enough like that to me that I'm guessing there might be something amiss with that 'come to a stop' mechanism, rather than with the motion/sync of the claw in general -- though I suppose that's possible. Good luck. _______________________________________________ FrameWorks mailing list FrameWorks@jonasmekasfilms.com https://mailman-mail5.webfaction.com/listinfo/frameworks
