Convertible Top not going all the way up???

It used to be that when it was about a foot from being all the way up, it would press through what seemed to be a point of resistance and then flop down on top of the windshield. Now it comes up slowly and then just stops when it's about a foot from the windshield. I can then pull it down the rest of the way by hand.
What is causing this? How do I fix it?
Drive motor going weak?
Is there lubrication or other maintenance that I need to do?
Thanks!
Waxxing_Gibbous
(aka CrofTTy)



