Cleaning the Scroll Wheel for Microsoft Wireless Mouse 5000

I like Microsoft’s wireless mouse for many reasons:

Factory fresh Microsoft Wireless Mouse 5000

Left: Factory fresh Microsoft Wireless Mouse 5000. Right: Disgusting original after years of usage

Although the mouse worked well initially, occasionally the scroll wheel stops working, is slow, only works in one direction, or is jerky. Part of the cause of the scrolling problem is animal hair from my loving cat, Raisin. She sleeps in a cardboard lid on my desk to be near enough for petting between paragraphs.

Miss Raisinetta in her box by my side

Miss Raisinetta in her box by my side wondering why I am not scratching her this very instant

A close inspection of the mouse’s scroll wheel reveals it is clogged by more than just hair and, regardless, that the rubber surface is eroding as well.

Filthy mouse scroll wheel

Filthy mouse scroll wheel. Gross! Disinfect it immediately.

The rubber grip on the scroll wheel is definitely the weak link of this device. Everything else will still work fine on this mouse long after the scroll wheel wears out. Avoid stretching the rubber in a vain attempt to clear scrolling issues. Instead, open the mouse for a thorough cleaning.

This will be easy. We'll just peel off the label in the battery compartment, as that’s where most companies hide screws.

Test point connection underneath battery label

Test point connection underneath battery label

Rats!

Okay. Leave your battery compartment label intact. Only a set of test points exist underneath the label.

Assuming that modern manufacturing eschew screws due to material cost and labor, I next guessed that the mouse snapped together similar to an iPhone. I simply needed to pop it or pry it apart with a tiny screwdriver. Nope! That only caused aesthetic damage to the case.

Ah ha! Peeling back a corner of a plastic glide pad on the bottom of the mouse reveals a screw.

Torx screw underneath mouse glide pad

Torx screw underneath mouse glide pad

There are four screws total -- one under each corner. You should not remove the glide pads completely. Instead, only peel them back enough to unscrew the fastener.

Speaking of which, you'll need a special screwdriver. The screw head is a fairly small size of Torx; a T6. You can buy a T6 screwdriver alone or as part of a miniature set if you plan to have further adventures in technological salvage.

Head of T6 torx screw

Head of T6 torx screw

After removing the screws, the mouse should split open fairly easily, depending on how much candy bar residue is holding it together.

Looking inside -- there’s your problem, lady!

Scroll wheel inside wireless mouse clogged with hair

Scroll wheel inside wireless mouse clogged with hair

Hairs, fibers, dust, and human oils collect around the scroll wheel. Fortunately, the entire assembly can be popped out for cleaning, almost as though the designer leaned green enough to make it user serviceable.

Be careful with the spring underneath the assembly, as it is not affixed to anything and may drop to the floor. (Not that it happened to me, of course.)

Scroll wheel assembly showing clean interrupter slits

Scroll wheel assembly showing clean interrupter slits

After pulling out questionable material with tweezers and bursts of compressed air, the reason for the interference with moving the scroll bar becomes apparent. There are little slits in the scroll wheel (see above) that pass or block light as your finger rolls the wheel. If these slits are blocked, the mouse is unable to detect any movement.

If you are interested in learning more about interrupter emitter-detector pairs, check out articles on photo interrupters and encoder wheels for distance measurement.

Inside the Microsoft Wireless Mouse 5000

Inside the Microsoft Wireless Mouse 5000

Above, you can see the LED that generates the light that should intermittently pass through the rotating mouse wheel. Also, you can see the light-sensitive sensor that detects the light. Make sure no foreign contaminants are blocking those parts.

After reinserting the scroll wheel assembly, pop the mouse back together. Reinsert the screws and pat down the edges of the glides.

Ta da! Your mouse is clean enough for another year! Now go wash your hands.