I have an older Genie screw drive (sd9500) which all of a sudden has started acting odd. It stops partway down and partway up. I tried cranking up the the safety adjustment and even disconnected the safety switch (when there is too much vibration the safety hub hits this switch). I thought it might be the motor thermal fuse but the motor starts right up after a press of the button....doesn't need any cool down time. Now the door goes up a little and down a little....after a minute it tries again. Btw....it never had a photo sensor safety device so that gets ruled out.

Being an older unit it is pretty basic....I just can't figure what else it could be. Thoughts?