A quick learner from Miami fl says:
June 1, 2016
Hello I have a few windows that the crank does not allow me to close the window before the crank un screws from the operator and yes the set screw is vert tight. Looks like it jumps of the cog inside? Should I just replace the whole thing or should I try and fix it? Its happening more and more as the years go by with these windows. And I am in Miami Florida. Thank you for any help you might be able to give me. Happy to send pics if need be.
Tom from SWISCO responded:
June 2, 2016
Sounds like the worm gear is coming out. If this is the case, you'll need a new operator entirely. We can help you replace it, but we will have to see a picture of the whole thing removed from the window. Let me know!