Desperate for Logitech MX 300 Mouse Help



New Member
Hey, I recently spilled some coke in my new Logitech MX 300 Laser Mouse and was forced to open it up and clean out the mess. After numurous attempts, I got the mouse back to normal, except for one thing. I had an extra spring left after putting the mouse back together. I learned that it was a part of my wheel device in that now my wheel device rolls continuosly instead of the "interval roll" it is supposed to do.

If anyone has the same mouse or just knows in general could aid me in any bit on how to put this spring back it, this would be greatly appreciated. I attempted Logitech support yet they said I "violated my warranty" by opening up the mouse. So much for that idea. Anywho, any help would be greatly appreciated. Thank You


New Member
I dont have that particular mouse but I've pulled several different types apart in the past and am pretty sure I can guess roughly where that spring goes and what it does.

There are various methods of providing the "notching" action on the wheel. One method is to have a small notched disk (like a gear cog) that rotates on the same axel as the wheel. A compressed spring is placed underneath the wheels axel such that it contacts with this "gear cog" and pushes upwards against it. As the mouse wheel is rotated, its axel rotates, and the little "gear cog" notches "click click click" against the spring.

Normally in such an arrangment the spring has a small ball-bearing or similar on top of it, so that the spring itself does not make direct contact with the "gear cog" but rather it pushes the ball bearing (or similar) up against the cog to provide the notching action. If your spring is "naked" on the end then perhaps you have lost the ball-bearing though it should be easy enough to find somthing suitible to do this job (like another ball-bearing for example).

Hope this helps.