CNB,
Thanks for your reply. I realize now that the MTO ball is 38.1mm (~1.5"). Your brother found a Logitech or MS ball? If MS, could it be for sale or trade? Finding a replacement is much more difficult than I imagined it would be. Saluc (maker of Aramith billiard and pool balls) manufactures legitimate trackballs, but I cannot rouse a response from them re: buying one.
Chimera,
Great story-- as long as there are no wires out the side, or duct tape holding it together, the satisfaction of keeping that one alive over the years is almost worth more than the tangible value of having a working input device alone.
I've refurbished my TBO to include replacement of the infamous bearings, but have not had the same level of success using a different ball. Swapping the bearings was super simple, and I took several pictures to post one day. Now, even with the lowest possible static friction, the undersized Logitech ball rocks (tilts/stutters) in he MS trackball cavity as opposed to rolling. Especially true along x axis, and even more prevalent in the positive/right direction. The ball essentially lifts out of the bottom hole where it rests, and travels around the daggum socket, resettling after it's released.
So now, after unsuccessful Logitech implementation, I'm back to searching for a suitable replacement. If anyone wants to send me their MTO ball, I will gladly sponsor you by affixing your call sign or business logo somewhere prominent. I'm thinking my sponsored Nalgene bottle at work. You could be among such greats as: East Carolina University, Flying Dog Brewery, SweetWater Surf Shop, [awesome gov't agency], etc. Just let me know.