Strange Problem with Opti-Pac

[toolaa]

I just installed a new Opti-Pac to three rotary controls.  Player 1 X-axis works fine, player 2 X-axis works fine, but player 1 Y-axis has a strange problem.

When I turn the dial the mouse moves, but it is very jumpy and it takes several turns to get it to even move a few millimeters on the screen. 

I checked the connections but they look just fine.

Any ideas anyone?

[RayB]

Dirt in the optic?
Broken optic wheel?

[toolaa]

Checked that and cleaned the optics with Iso.  I decided to swap the x and y axis and the problem went away on both axis.  Swapped them back and it's back.

Maybe Andy will read this...