...Open up the drive and look at it carefully...

Click to expand...

And while you have it open, also look very carefully at the hub shoulder surfaces that try to assure that the disk rotates in a plane with minimal wobble. If there is too much lint, or worse one grain of grit caught on the flat circular friction ring clamping zone, the disk will have an up and down wobble that is small near the center, but increases as the head tries to track and read data farther outwards.