How to use
- Point at the test area and scroll slowly down for a few seconds, one notch at a time.
- Then scroll up the same way, and finally fast in both directions.
- Red marks on the timeline are steps in the wrong direction. More than a few means a worn encoder.
Frequently asked questions
Why does my wheel scroll the wrong way?
The wheel’s encoder wears and gets dirty over time, so it sometimes reports a step in the opposite direction. It is common in older mice and often appears as page “jumping”.
Can I fix a jumping wheel?
Blowing compressed air into the wheel and scrolling quickly back and forth sometimes helps. For a lasting fix the encoder or the mouse needs replacing.
What do notched and smooth mean?
A notched wheel sends equal steps you can feel. Free-spinning and high-resolution wheels, and touchpads, send many small, varying steps.