Kensington Expert Mouse: Unit 3

A week or so ago, the scroll ring on the Kensington Expert Mouse trackball at my left hand failed completely. Unlike the previous repair attempts, tweaking the IR emitter-detector pair positions did nothing. Tried it on three different PCs and five different operating systems with the same result: the ring stayed dead.

Fortunately, this one was a warranty replacement for the dead Unit 1 I bought some years back and was still within its 5 year warranty, so when I contacted Kensington tech support with the story they immediately shipped a replacement. It just arrived and works fine.

The scroll ring detents seem much smoother on this one, so I haven’t taken it apart to remove the magnetic latch and don’t know if they’re using a different quadrature sensor. One can but hope.

Kensington Expert Mouse - ball bearing

Kensington Expert Mouse - ball bearing

For what it’s worth, an absolutely brand new ball barely moves on those three jeweled bearings (one marked with the yellow oval in the picture). Just rub the ball on one side of your nose to add some skin oil: shazam it spins like glass on ice.

They don’t mention that trick anywhere in the meager instructions…


  1. #1 by madbodger on 2012-03-29 - 10:33

    Heh, it’s an old darkroom workers’ trick too. A little “nose grease” can greatly reduce the visibility of a scratch in a negative.

  2. #2 by david on 2012-03-29 - 12:46

    Indeed. Works pretty OK on DVD scratches, too.

  3. #3 by Frans on 2012-06-18 - 18:35

    I have two with the same problem and read through my warranty stuff, but it only mentioned the regular 2-year warranty. Since I bought them in ’08 maybe I’ll see if they’re nicer than their own documents suggest.

    • #4 by Ed on 2012-06-18 - 22:09

      two with the same problem

      Talk about a common-mode failure!

      • #5 by Frans on 2012-06-20 - 06:04

        There’s a (years older) third trackball on which the ring still works fine, but unfortunately some of the buttons on that one were damaged by a liquid spill — besides it’s my wife’s, so it doesn’t help me much. In fact the scrollring runs much smoother on that trackball than it ever did on either of the newer two.

        • #6 by frenzie on 2012-06-20 - 06:10

          Just to clarify, I mean it runs significantly smoother mechanically. Even though the scrollring on my Kensington Expert Mouse doesn’t result in computer input anymore, it still goes round in circles just fine. But not in the smoothest manner, like I said.

        • #7 by Ed on 2012-06-20 - 08:04

          the scrollring runs much smoother on that trackball

          As nearly as I can tell, there’s no actual bearing in there under the scroll ring. It’s just two ordinary plastic surfaces sliding against each other, with all the grittiness you’d expect. Maybe the metal aperture ring slides on the plastic, but … yuck!

        • #8 by frenzie on 2012-06-20 - 11:36

          I know, I noticed that when I opened it up to try the fix you detailed elsewhere (which worked for a little while). I can only assume the older variety might actually have some kind of bearings.

  4. #9 by frenzie on 2012-10-26 - 16:06

    They don’t mention that trick anywhere in the meager instructions…

    By the way, the instructions do actually advise you to rub it in the palm of your hand. But I’m just commenting to leave a reference to this older post:

    • #10 by frenzie on 2012-10-26 - 16:07

      Wait, I meant that the other way around. Could you link from the older post to here? :P

      • #11 by Ed on 2012-10-26 - 17:14

        There’s now a trackback from the Scroll Ring Tweakage post to this one (Unit 3), which I think you just generated by adding the link. [grin]

        I try to backlink as needed (each one automagically generates a corresponding forward trackback link), but if there are many previous posts I can’t hit ’em all. In that case, you gotta dump the obvious keywords into that search box and hope the right thing pops up.

        • #12 by frenzie on 2012-10-27 - 04:06

          Oh, I might’ve missed that trackback. *smacks forehead*

          • #13 by Ed on 2012-10-27 - 08:07

            Nope, it wasn’t there until you added the note: that’s the link from the future!

            I think, anyway. Couldn’t find a link in the post itself, but I’m getting really good at missing the obvious…

        • #14 by frenzie on 2012-10-27 - 08:12

          It’s the word repair. ;)

  1. Xubuntu 12.04: Some Steps Forward, Some Steps Back « The Smell of Molten Projects in the Morning