Fleemo wrote:
....
door rolls smoothly, then gets difficult to roll, then rolls smoothly
again at various points in the opening process. It gets difficult to
roll when each door segment reaches a 45-degree angle during the
transition from horizontal to vertical.
....
Sooo, if the springs have not actually broken, does it sound like
something that a spring *adjustment* would correct? ...

No.

The change as the door opens/closes as each section bends is the clue it
ain't spring force that's the problem.

Sounds like either loose or worn or misaligned (or combination of all)
rollers/supports.

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