10 yo Craftsman 1/2 hp problem

[Always something]

Opened the door with the button one day, an hour later tried to close and only a grunt. Sensors are fine. Disengauged door from rail, door closes fine. Hit the button with no strain(door) on the motor and still a grunt.

Lowered the unit and removed the chain. Hit the button and the sprocket jumps/grunts 1/4 inch in the up direction with every push of the button. Adjusted the up limit (-) on the side and still the motor grunt with 1/4 inch movement.

Any ideas?

[Always something]

With the chain and unit cover off. The contacts to stop the upward movement of the door were touching like normal. Turned the up limit screw(+) so the contacts untouched to see what would happen. Pushed the button and the motor ran in the door-up direction again till the contacts meet and stopped the motor like normal.

Why will the motor not revearse, what am I missing.