Mouse Diagnostic

Scroll Wheel Tester

Test mouse scroll wheel direction, step lines, and encoder reverse jumping faults online for free. Detect rotary encoder jitter and jumping on gaming mice.

SCROLL MOUSE WHEEL UP AND DOWN HERE IDLE 0 total scroll steps

Scroll Encoder Health Benchmarks

Scroll 20 notches in a single direction and monitor the live delta vector:

Consistent Direction (Healthy)

100% of scroll ticks register in the intended direction with deterministic delta step values (e.g. ±100px).

Occasional Direction Jitter

1 out of 10 ticks scrolls backwards. Caused by early dust buildup or loose rotary encoder housing claws.

Severe Reverse Jumping

Frequent opposite jumps or zero resistance free-spin. Requires contact cleaner spray or encoder replacement.

How to Get Started

Just three steps to run a complete controller test and understand your controller's health status.

Connect Controller

Connect your controller to your computer via USB cable or Bluetooth. If the browser doesn't respond, press any button on the controller to activate the connection.

Button Detection

Press each button in the visual interface and confirm the corresponding area lights up on screen. This helps troubleshoot unresponsive or double-clicking buttons.

Sticks & Vibration

Rotate the sticks to check linearity and drift issues; click the vibration test button to feel if the left and right motor feedback is working properly.

What would you like to do next?

Select a diagnostic calibration suite, deadzone analyzer, or high-frequency overclock tool.

Fix

Repair & Calibration

Calibrate zero-point offsets or follow step-by-step repair guides.

WebHID Calibration

Optimize

Game Deadzones

Calculate exact radial vs axial deadzone overlays for Fortnite, Apex, & COD.

Deadzone Calculator

Telemetry

Overclock & Circularity

Verify browser-observed update timing Hz stability and statistical circularity grades.

Hz & Circularity Tools

The Mechanics of Rotary Encoders & Reverse Scroll Faults

The vast majority of gaming and office mice utilize mechanical rotary encoders (manufactured by TTC, Kailh, ALPS, or F-Switch) to translate wheel rotation into digital scroll steps.

2-Phase Quadrature Output (Phase A & Phase B)

Inside the encoder, a 3-pin disc with conductive radial spokes rotates past two spring-loaded wiper fingers:

Scrolling Down: Phase A leads Phase B (Phase A closes first, then Phase B closes).
Scrolling Up: Phase B leads Phase A.
The Reverse Jump Failure: When microscopic dust or oxidized lubricant coats the spoke tracks, Phase A can drop out momentarily. The mouse microcontroller misinterprets Phase B closing first, sending an erroneous Scroll UP packet during an intentional Scroll DOWN motion.

Mechanical Encoders vs. Optical Slotted Encoders

While mechanical encoders offer distinct tactile notches (steps), they degrade with heavy gaming use (such as jumping in Apex Legends / Counter-Strike bound to scroll wheel). Optical scroll systems (infrared beam passing through a slotted wheel) eliminate physical wear entirely.

Controller Hardware Glossary & Tips

Stick Drift & Deadzones

Stick drift occurs when analog sticks register input without being touched. This is typically caused by physical wear in traditional carbon-film potentiometers. A deadzone is a software-level threshold (e.g., 5-10%) applied to ignore these microscopic false inputs.

Hall Effect Sensors

Unlike traditional ALPS potentiometers, Hall Effect modules use magnetic fields to measure stick position. Because there is no physical contact or friction between the internal components, they are virtually immune to wear-induced stick drift, drastically extending the controller's lifespan.

Polling Rate (Hz) & Input Latency

Polling rate is how often your controller sends data to your device, measured in Hertz (Hz). A standard Bluetooth connection yields around 125Hz (8ms latency). Overclocking or using a wired USB connection can push this to 500Hz-1000Hz (1ms-2ms latency), critical for competitive gaming.

Circularity Error

When you rotate a joystick along its outer edge, a perfect module should trace a mathematically perfect circle. Circularity error measures the deviation from this perfect circle. High deviations (>15%) can result in uneven diagonal movement speeds in FPS games.

Frequently Asked Questions

Everything you need to know about testing your controller.

How do I test my mouse scroll wheel for reverse scrolling and jitter online?

Place your cursor over the test pad above and scroll your mouse wheel continuously in a single direction (e.g. downward). If the real-time indicator flashes "REVERSE JUMP DETECTED" or detects positive deltaY during downscrolls, your mechanical rotary encoder is failing.

What causes mouse scroll wheels to jump in the opposite direction?

Reverse scroll jumping is caused by dust, hair, or dried lubricant contaminating the internal metal contact brushes of the mechanical rotary encoder (TTC, Kailh, or ALPS). This creates electrical signal bouncing between Phase A and Phase B quadrature channels.

How do I fix a mouse scroll wheel that jumps or scrolls backwards?

Turn your mouse upside down and scroll rapidly against a clean mousepad; blow compressed air directly into the scroll wheel gap; or apply 1–2 drops of 99% isopropyl alcohol / electronic contact cleaner into the encoder housing and rotate 50 times.

What is the difference between mechanical and optical scroll encoders?

Mechanical encoders use rotating metal wipers that slide against conductive tracks, causing wear and reverse scrolling over 1–2 years. Optical encoders (used in Razer DeathAdder V3 and Zowie mice) use an infrared beam through an encoder disc, eliminating reverse jumps forever.

Does this tool test horizontal scroll tilt wheels?

Yes! Tilting the scroll wheel left or right on supported office and productivity mice (Logitech MX Master series) emits deltaX events that will register in the live telemetry readout.

How this test works & its limits

This test reads your controller through the browser's standard Gamepad API — no drivers, no installs, nothing leaves your device.
Readings depend on connection mode: Bluetooth reports at lower rates than USB. Compare like-for-like (wired vs wired).
We measure the input reaching the browser — display lag and game-engine queues are outside this test's view.
A clean reading now does not guarantee no drift in-game: deadzones differ per game, and wear develops over time. Use the Drift Timeline to track yours.
This is a diagnostic, not a hardware-lab certification. For repair or RMA decisions, confirm with a second run or second tool.

Read the full methodology

100% Client-Side

All Gamepad API data stays in your browser. Zero tracking or data collection.

Instant Results

No downloads, plugins, or software installation needed. Works instantly.

Free Forever

No paywalls, subscription requirements, or hidden usage limits.