[amsat-bb] G-5500 stuck problem

Have a G-5500 and suddenly the rotor stops moving clock-wise past 180. I stood under it and it makes no particular noises at that point, just stops perfectly at 180. Was working the day before and flawlessly for the last 4 years.

It stops so quietly, it almost sounds like the limit switch or the controller is stopping the motor. The elevation works perfectly and the rotation works fine from zero to 180. If it were a bad gear or something like that, I would expect it to grind or make some funny sounds

It is a royal pain to take the thing down; any ideas on debugging without taking the thing down?

Michael