badgolferman wrote:
Liftmaster Formula I.

When I hit the button the motor makes noise but the belt doesn't move. The
door moves on the track freely when I lift it manually. Examining the belt
I see the rubber has separated near the motor and only the steel belts are
visible. There is maybe an inch or two of slack in the belt when I pull on
it. This belt seems to be the problem to my untrained eye. Is this
something I can fix on my own?


Sounds like belt is a toast.
How about replacing the belt? If you don't try you'll never learn.
There is many Youtube how to do out there. My GDO is screw drive type,
no belt to replace or wear out!