[C] Date: Sat, 20 Mar 1999 02:07:40 -0800
From: Matt 
Subject: Trackball problems/resolutions

I just performed surgery on my Aero again this evening. My trackball was
not working very well, so I decided to open it up and see if I could fix
it. The trackball worked fine left and right, but did not work very well
up and down. (Note: I'm using the original ball, but roughed up with
sandpaper as per the FAQ) Anyway, I removed the trackball assembly from
the case and discovered that by removing two screws from the bottom of the
circuit board, I could remove the top half of the trackball assembly. What
I found inside was pretty interesting.

The top of the trackball assembly contains the "bowl" for holding the
trackball and the rollers. The rollers are on a small metal shaft that
fits into a slot in the side of the assembly. The roller is actually on
the far end of the shaft. On the other end of the shaft is wheel with
teeth similar to a gear. A spring touches the shaft in the middle, halfway
between the "gear" and the roller. It is this spring which holds the shaft
in the slot in the side of the assembly. 

Affixed to the circuit board are two housings that contain an LED and a
photocell. In each housing, the LED faces the photocell. When the upper
trackball housing is fitted to the circuit board, the two "gears" slide
into a slot between the LED and the photocell. 

I discovered that a bunch of fibers had accumulated on the roller shaft
and had also wrapped themselves around the retention spring. I figure that
as the shaft turned, the fibers pulled on the spring, increasing friction
and making it harder to turn the shaft. Cleaning these fibers off the
shaft produced a noticeable improvement in trackball performance. Up and
down movement works perfectly now. If you've been having a similar problem
and are brave enough to open up your Aero (or you have your Aero open for
any other reason) check out the trackball assembly. 

(One bit of warning: There is a small pin and spring that makes an
electrical connection between the circuit board and the trackball
retention ring. I'm not sure what it does, but the spring is easy to loose
when you open things up. --Matt

[C] From: GStew 
Date: Tue, 27 Jan 1998 23:07:27 EST

1. Clean the rollers with Q-tips soaked in rubbing alcohol.
2. Use a pin to carefully remove any lint and hair wrapped around the roller
   axle wires.
3. Use a pin to carefully position the rollers equidistant on the axle wires.
4. If the trackball is smooth and shiny, rough it up with 220 or so grit
   sandpaper.

This should get it moving freely again. Then, keep a small spray bottle of
rubbing alcohol around to spray the ball when it sticks... that'll get it
going again for awhile... but eventually, you have to clean it again.

[Q] What can I do when my trackball is not responding?

[A] First make sure you do not still have the original smooth trackball. This
is a known and very common problem. Replace it with the new matte-finish ball
from Compaq or sand it slightly (see above).

In order to clean the trackball you suspend the machine (turning off is
probably better), twist the locking ring to the left, remove it, tip the unit
'til the ball falls out, and then clean rollers and such with a lint-free cloth
and at least 70% isopropyl alcohol. Camera lens paper is good for this, or use
SPONGE-tipped swabs. Cotten-tip swaps such as Q-tips can leave fibers in there
which will mess things up.

[A] Sounds like a case of the classic dirty trackball. Use the "Compaq Learning
Center" and read how to get it out and clean it. One of the rollers is slipping
which makes it look like one dimension is fixed. It happened to me all the time
until I got the new trackball from Compaq. Now it just happens maybe once every
other week and I just wipe around inside the trackball hole for a few seconds
using my shirt tail and pencil.