68kMLA Classic Interface

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Assimilation Process trackball
Posted by: waynestewart on 2026-01-29 15:14:47
I have out my Kensington and Assimilation Process (AP) trackballs.

The Kensington trackball works fine but the AP trackball has a tracking issue. After a bit of cleaning tracking was good in one direction. If I move the rollers manually it works well. I swapped the roller assembly and now it’s good in the other direction. It appears that the rubber roller is slipping on the trackball. I was thinking about sanding the rubber roller to increase grip but that’s a one off thing. So before I try that I thought I’d see if anyone had any suggestions.AP.jpg9 pin.jpg
Posted by: adespoton on 2026-01-29 20:26:18
Shrink tubing over the roller?

The problem is, if you abrade it you’re making it smaller and more uneven.
Posted by: joevt on 2026-01-29 21:35:54
Need a closer look at the rubber roller. Is it a rubber o-ring around a plastic cylinder that has a groove for the o-ring? If so, replace the o-ring. If not, 3D print a replacement rubber roller? Or 3D print a plastic cylinder with a groove for an o-ring?
But before that, search for "rejuvenate rubber". I have no experience with any of that though.
Posted by: waynestewart on 2026-01-30 21:19:54
The rubber roller is solid rubber, no O-ring. It does have a spring that presses the roller against the ball. It wasn't moving in either direction at first. I stretched the springs a little and one direction started working normally but not the other.
I doesn't have o-rings but maybe I'll try adding a couple.
Posted by: Joopmac on 2026-01-30 22:53:44
I have two of these. The Colour of the ball always seems strange
Posted by: waynestewart on 2026-01-31 12:28:29
I have two of these. The Colour of the ball always seems strange
Feels like the ball needs retrobrighting. Fortunately when Kensington acquired them, they changed the trackball colour.
Posted by: waynestewart on 2026-01-31 12:36:10
Success. I tried an O-ring that was a good fit but there wasn't enough clearance between the roller and the circuit board. Then I stretched a really tiny O-ring with a 2mm center over a tapered dowel and was able to get it on with just enough clearance. 20260131_122212.jpg
Posted by: Joopmac on 2026-02-01 01:18:53
nice! i might try this oneday=)

yes, i also have a later type with numeric pad, and that one is nice and gray
Posted by: waynestewart on 2026-02-01 13:22:44
Sometimes I find odd things interesting.
With both trackballs out, I was noticing the AP logo on the plastic of the 9 pin connector. On the Kensington they eliminated the middle but you can still see the edge.
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