I noticed one of my disk speed is 40% slow according to APTEST. I attempted to tweak it up by adjusting one of the two potimeters on the circuit board, however, it seems with it all the way counter clockwise won't allow it to get better than the 40% slow.
Anyone having a good quality schematic of that circuit board in the disk II drive? If you have the ability to force the schematic color so it is white on black background that would be most helpful.
Also, what does the other potemeter do?