What this test checks
- Dead zones — areas of the screen that do not register touch input at all.
- Touch accuracy — whether your finger position matches the reported coordinates.
- Coverage — how evenly touch points are distributed across the entire display.
- Multi-touch — whether the screen tracks multiple simultaneous contacts.
How to perform the test
- Tap Start to begin the touch test.
- Slowly drag your finger across the entire screen surface.
- Cover the edges, corners, and center — dead zones often appear near screen borders.
- The test builds a heatmap showing every registered touch point.
- Check the heatmap for gaps — areas with no marks may indicate dead zones.
What are dead zones?
Dead zones are regions of a touch screen that fail to detect finger contact. They can result from manufacturing defects, physical damage, or worn digitizer components. Common signs include unresponsive keyboard keys near screen edges, dragging that stops unexpectedly, or tap targets that require repeated attempts. Dead zones often grow over time if the underlying hardware is deteriorating.
Troubleshooting
- Clean the screen — oils, screen protectors, or moisture can interfere with touch detection.
- Remove screen protectors — thick or low-quality protectors may create dead spots.
- Restart the device — a software glitch can temporarily disable parts of the digitizer.
- Test with different apps — if dead zones appear in all apps, the issue is likely hardware.
- Check for physical damage — cracks near the affected area often indicate digitizer failure.