Fixing a problematic optical mouse

December 11, 2006

I have had a Microsoft Basic Optical Mouse for around 2 years now. And in these two years I’ve mistreated it more than any other piece of computer hardware I own. Dropping it many times, falling asleep on it, stepping on it being some of the abuse it survived. And it worked well for me without any trouble. Until yesterday.

The left mouse button just stopped working. Out of 50 clicks it would maybe respond to one. I gave it a thorough shaking in disregard to the sensitive optical equipment it carried but it didn’t do me much good.

Was it time for me to buy a new mouse? The thing was still in its warranty period that extended to 3 years as far as I know. So I could turn it over to an MS authorized service center for fixing. But it didn’t seem worth the time, effort and uncertainty involved. So I decided to try and fix things myself and in the process void my warranty by removing the seal covering the screw that attached the mouse cover to the body housing the chip/optical sensor.

The inside of a mouse is not too interesting. But you ought to take a look sometime. The scroll wheel is toothed and is placed between an LED and an optical sensor to detect the movement of the wheel. One thing that I noticed was that most of the weight of the mouse was artificially introduced in the form of large piece of iron screwed to the body to make the otherwise “too light” mouse easy to glide on a surface. So every time that I used to drop the mouse, I was needlessly worried about breaking things inside. It is only the body that suffers a shock due to the attached weight. The stuff inside seemed to be quite safe from the effects of a fall. I unscrewed the chip inside. Cleaned out the dust. Moved the mouse around my desktop by gliding only the optical sensor-chip around without any body. Felt rather geeky doing that :) . Now for the tense moment…trying out the left button directly by pressing it with a ballpen (I had removed the outer body). The button worked fine ! Yay !

So I cleaned out 2 years of accumulated dust and dirt. Screwed things back in place. Made sure that the button on the body was aligned to the button on the chip inside and dealt with rather irritating interlocking mouse-body parts in the process. And screwed the parts together.

That’s it. My mouse is now as good as new. A neat amount of time, hassle and money saved with 20 minutes of work. Most people, being technophobes, would probably have called their computer salesman who would have happily sold them a new optical mouse for around Rs.500 and offered to do them a favor by taking in their old, “broken” mouse for Rs.100 or so.

Just takes a moment to try and fix things. Often, the problem is quite simple. More people should give it a try.