I was wondering if anyone is familiar with how the Revere 8 rheostat should respond. It goes immediately from the slow speed to fast at a certain point when the knob is turned. The design is similar to a Kodascope 16. But in that machine the speed increases gradually from slow to fast. I cleaned the rotor with alcohol and contact cleaner with no change. Is that just the way this one is supposed to work ? It wouldn't be a big deal normally, but sometimes the slow speed seems a little slow for silent and more often the fast speed seems a bit fast for 24 fps. Thank you for any ideas you might suggest.