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My Mouse Doesn't Work

-----Original Message-----
From: adam taylor []
Sent: Wednesday, December 19, 2001 3:04 AM
To: Graeme McRae
Subject: I need some help with technology..

Question: How do you fix a mouse...

...that has the cursor move right and left but not up and down. I really need to know and fast. I just thought that I may as well ask you since you are some engineer technology person. Thanks and Bye, and I really thank you for the help you gave me.

Answer: If you open the mouse...

...and take out the ball, you will see that it rubs against two thin cylinders -- about as thin as a pencil lead. The cylinders are set at right angles to one another. One is for vertical, and the other is for horizontal. Each cylinder has a toothed wheel attached to it. When the ball rubs the cylinder, the cylinder turns, making the toothed wheel turn. A tiny light source is interrupted by the teeth of the toothed wheel, and this is how the mouse senses motion. If only the horizontal (or only the vertical) is working, it probably means that one of the cylinders has moved out of place. This could be caused by slamming the mouse down, or possibly just by old age. It is possible the plastic support for one of the thin cylinders has broken.

Question: Why would a person slam his mouse...

...against a hard surface, possibly causing a plastic support inside it to break?

Answer: If the damage was caused by slamming...

,,,the mouse down against a desk or table, then it is possible that the user of the mouse had become frustrated. One cause of frustration is that the mouse pointer will, from time to time, appear "stuck". This is typically caused by dirt on one (or usually both) of the thin cylinders. To solve this problem, open the mouse, remove the ball, and slowly turn the cylinder with its attached gearwheel as you scrape the dirt off the cylinder with your fingernail. Then, when you put the mouse back together it will work like new for a week or two. You should clean it this way every few weeks, or whenever you notice the mouse pointer doesn't track well.