The fix ended up being quite simple, but not something I would have known to look at. The tech spotted the problem in seconds (literally!)... fixed it... then spent a few minutes telling me how to get another 20 years out of my already 20-year old opener. He inspected and observed the operation of the opener and door - and clearly explained to me what he was seeing that indicated that everything was in good shape. I was charged only for the standard service call, which I was aware of before setting the appointment.Richard D.