I'm using a WICO trackball that I have connected to an Optipac. The problem is, any time I move it up or down, it goes diagonal instead. If I try going up, it goes up and left. If I try going down, it goes down and right. I gave it a good cleaning, and my wires aren't crossed. Is this fixable, or do I need to purchase a new trackball unit? Thank you in advance.