On  1 Mar 98 at 16:45, Mark wrote:

> i'm lacking in technical jargon knowledge, so excuse the elementary phrasing
> of this question.  i have a relatively new mouse (about 2 months old) that
> has already gotten to the point where it's having trouble moving the
> cursor.  a few people and i have already taken out the ball and dusted out
> the interior; however, it's still acting up such that i have to pick up the
> mouse two or three times just to move to certain places sometimes.  i opened
> up the mouse again and found that the little roller that moves the cursor up
> and down is the culprit.  it doesn't appear dirty at all.  in fact, i don't
> see any dust particles and there's no noticeable buildup.  but whenever i
> try to finger it to move the cursor, the cursor doesn't move very far for
> the first few revolutions.  the left-right roller is still fine.  does
> anyone know what could be wrong with it?  i'm thinking that either it's
> still dirty and maybe i should pull out the cotton swabs and rubbing alcohol
> (is that adviseable?) or there's a loose connection somewhere.  any advice
> would be appreciated.  thanks.

  My first guess would be buildup on the roller, but you say you've
checked for that.

  Okay, that roller is connected to a wheel, about an inch in
diameter, with lots of spokes.  Motion of the roller is detected
because it interrupts light from an LED shining through the spokes to
a photocell.  If there's dust or something oin this spoked wheel, it
could interfere with this process.

  I had a mouse where one of the wheels seemed not to work, right
from day one.  My conclusion was that the spring on the thrid roller
(the one at 45 degrees to the other two) was simply inadequate, and
so the ball was not making sufficiently forceful contact with the
roller.  My solution was to return it and get a decent mouse instead.

David G