Scroll Wheel Encoder & Reverse-Jump Detector.
Is your mouse randomly scrolling up when you scroll down? Detect microscopic encoder bounce, reverse-step anomalies, and measure scroll speed.
Quick Answer • How to Test Mouse Scroll Wheel
To test your scroll wheel for erratic behavior, select your intended direction and spin the wheel continuously inside the test arena below. A healthy mechanical rotary encoder produces uninterrupted directional delta signals. If scrolling downward momentarily registers upward pulses (reverse jumps), the internal contact wipers (such as TTC, Kailh, or ALPS encoders) are suffering from dust contamination or mechanical wiper oxidation.
Verified by The MouseTests Hardware LabRead Encoder Methodology →
Target Direction:
Total Steps
0ticks
Reverse Jumps
0errors
Encoder Grade
100%healthy
Peak Velocity
0px/s
Hover Here & Spin Your Wheel Continuously
Spin the wheel DOWN in one continuous direction. If the encoder slips backwards, it will be highlighted in red.
Page scroll locked (won't move while spinning)
⚠️ REVERSE JUMP DETECTED! (Encoder Misread)
Real-Time Scroll Stream
Live TapeScroll ticks will stream here
Why Does Mouse Wheel Reverse-Jumping Happen?
1. Dust & Pocket Lint:Most mice use mechanical rotary encoders (like TTC Gold, Kailh, or ALPS). Dust collects inside the notched wheel teeth, causing the contact wiper to momentarily short-circuit into the reverse direction.
2. Quick Fix (Inverted Fast Spin):Turn your mouse upside down on your mousepad and aggressively scroll the wheel back and forth for 30 seconds. This dislodges loose dust particles without requiring tools.
3. Isopropyl Alcohol / Contact Cleaner:If spinning doesn't fix it, applying one drop of 99% isopropyl alcohol or WD-40 Specialist Electrical Contact Cleaner into the encoder housing usually restores 100% clean scrolling.
Looking for in-depth teardown and repair steps?Read Full Scroll Wheel Fix Guide →