GearCheckHow to find touch screen dead zones
- Remove any case edge that covers the screen and wipe the glass clean and dry.
- Start the full-screen test so the edges and corners are included.
- Swipe slowly in rows from top to bottom, then in columns. Every square you cross should turn green.
- Look for gaps — a square or line that stays empty is a dead zone. Try it again with a lighter and firmer touch.
Touch screen problems and fixes
| Problem | Likely cause | Try |
|---|---|---|
| One area never responds | Damaged digitizer, screen protector air bubble | Remove the protector and test again |
| Touches register in the wrong place | Calibration (Windows tablets), damage | Windows: “Calibrate the screen for pen or touch input” |
| Screen taps by itself (ghost touch) | Dirt, moisture, faulty charger, damage | Clean the screen, unplug the charger and test again |
| Lines break up while drawing | Low sampling, power saving, damage | Disable battery saver, restart the device |
| Fewer touches than expected | Device limit or palm rejection | Compare with “Device supports” |
Before you buy a used phone or tablet
Run this test on the spot: it takes a minute and reveals dead zones that are easy to miss when only tapping app icons. Also check the display with the dead pixel test, the microphone with the mic test, the cameras with the webcam test and the speakers with the speaker test — all from the same browser.
Frequently asked questions
How do I test my touch screen?
Press Full-screen test and slide one finger slowly over the whole screen, row by row. Each square you touch turns green. Any square that stays empty after you’ve swiped over it is a dead zone where the screen does not register touch.
How do I test multi-touch?
Put several fingers on the screen at once. “Touches now” shows how many are detected, and “Most at once” keeps your record. Most phones and tablets detect 5–10 touches; “Device supports” shows the maximum your device reports.
What causes touch screen dead zones?
A cracked or damaged digitizer, a thick or bubbled screen protector, moisture, or a loose internal connector. Ghost touches — the screen reacting by itself — are often caused by a dirty screen, a faulty charger or a damaged digitizer.
Does this work with a stylus or on a laptop?
Yes. Stylus and pen input draw just like a finger, and on touch-screen laptops and monitors the test works the same way. It also works with a mouse, so you can try it on any computer.