When I try to turn the knob clockwise, it moves a very few degrees and then stops. I can see the wheel on top of the camera turning counter-clockwise, toward the lower numbers. The sprocket wheels inside the camera also try to turn to the right. Is that correct? Is there anything I can look at or lubricate to free up that mechanism? I don't see any movement of the shutter curtains with the slight movement of the knob.
Also, what is the silver button at the top right on the back of the camera, next to the down arrow? Is that some kind of release, and for what? (I just discovered that the numbered wheel on top spins freely toward the lower numbers when it is depressed, so it must be some kind of counter adjustment.)