Zip Dee awnings sometimes have a lock feature called a Z- lock.
This is fitted into the forward end of the awning tube.
These devices get water into them over the years and tend to seize. This will cause the awning to act as though the spring is shot or seized.
Zip Dee service will tell you, that if the awning will roll on its own to any degree, the spring is not the problem.
I had the same problem and assumed the spring was alomost shot. I called Zip Dee and talked to them. They sent me a 98 dollar Z-Lock. When I replaced the Z-lock, the awning rolled so easily, it almost snatched me off of the ground.
Replacement is simple and the new one comes with all parts and directions.
go here for directions www.zipdeeinc.com