I'm installing a 2 yo Furuno 1721 mkII and everything seems to be in good
condition except a sticky track ball..

Intially it wouldn't roll in any direction, eventually I got it to roll in
the vertical plane and now it works intermitantly in the horizontal.. This
seems to be a mechanical problem since the ball is actually loose in the
socket but when you push on it to roll, it feels like the tires on the pots
keeping it from rolling..

I notice also that when it is working it is not very smooth and difficult to
position the cursor..

Without opening it up, I think maybe the pots may have corrosion between the
shaft and bushing or bearing..

Has anyone ever worked on or explored a track ball set up???

Is there am cleaning or maintenance required on a track ball (the manual
doesn't mention it).

Steve
s/v Good Intentions