Quick answer
What this guide helps you determine
Separate page scrolling, screen protectors, app behavior and a consistently unresponsive physical area.
Begin with the observable browser result, repeat it under the same conditions, and change one connection, setting or application at a time. A browser result narrows likely causes but does not certify hardware or decide a repair.
Scope of this check
A dead-looking touchscreen area can be caused by page scrolling, a reserved edge gesture, screen protector, moisture, application layout or a digitizer region. A grid trail repeated after rotation helps separate a physical panel location from a software coordinate or app issue.
Step-by-step method
- Clean and dry the surface using the manufacturer method, then draw slow parallel lines across the bounded test grid with one finger. Do not use excessive pressure. Mark gaps by physical screen location.
- Rotate the device and repeat. A defect tied to the same physical glass area moves relative to page content; a page/layout problem may stay with the same on-screen control or coordinate behavior.
- Remove a case or protector only if it is designed to be safely removable, then compare the operating-system drawing or diagnostic app. Back up important data before any manufacturer-recommended reset or service step.
What to check first
Use these checkpoints to keep the comparison focused. Record the visible behavior rather than assigning a fault label too early.
- Draw slow trails across a grid
- Rotate the device and repeat
- Remove only accessories the manufacturer says are safe to remove
How to read what you see
| Observation | What it can suggest | Useful next check |
|---|---|---|
| The gap follows the same physical glass area after rotation | A protector, contamination or digitizer region is more likely. | Compare without safe removable accessories and seek support. |
| Only page edges fail | Browser/system navigation gestures may be intercepting touches. | Test farther inside and in another app. |
| The issue appears only in one app | Its layout, gesture handling or overlay is implicated. | Update/reset that app and report reproducible coordinates. |
Common mistakes to avoid
- Do not press harder on an unresponsive area.
- Do not heat, bend or strike the device.
- Do not remove a bonded protector or open the device without qualified guidance.
Build evidence another person can use
Write down the exact action, visible result and whether it repeats. Include the browser family, operating-system family, connection type and the single comparison that changed the result. Quote the observation directly—for example, “The gap follows the same physical glass area after rotation”—then add where it occurred and which comparison changed it.
Change one condition per comparison and return settings that have no effect. Follow model-specific manufacturer instructions before firmware changes, cleaning, disassembly or warranty action.
When to seek qualified support
If the same problem remains in multiple applications and on another compatible connection or computer, collect the repeatable observations and contact the manufacturer or a qualified technician. Stop using equipment that is physically damaged, unusually hot, wet, sparking or unsafe. Device Test Bench cannot inspect electrical condition or make a repair decision.
Privacy during testing
Our public tests process key events, pointer values, media streams and controller input locally. Do not send private recordings, complete typed text or device identifiers when asking for help. A short description of the behavior, browser and page URL is normally enough.
Questions readers ask
Can a cracked screen still show an image but lose touch?
Yes. The display and touch digitizer are separate layers and can fail differently.
Why does charging affect touch?
A faulty charger, grounding or electrical noise can disturb some capacitive screens; stop using damaged or unsafe power equipment.
Primary technical references
The following specifications define the browser APIs discussed in this guide. They are primary web-platform references, not product repair manuals.