Quick answer
What this guide helps you determine
Compare a pixel that remains dark with a subpixel that remains lit, using several solid backgrounds.
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 pixel usually remains dark because it does not emit the expected light, while a stuck subpixel can remain red, green, blue or another fixed color. Dust, a surface mark, image retention and scaling artifacts can look similar, so examine several solid colors before naming the fault.
Step-by-step method
- Clean only the screen surface with the manufacturer-approved method, set a normal comfortable brightness and reduce reflections. Enter the manual full-screen color test and inspect black, white, red, green and blue one at a time.
- Change viewing angle slightly without pressing the panel. A surface speck moves relative to the pixel grid or changes with focus; a pixel defect remains fixed at the same panel coordinate. Take a non-private photo only if warranty support requests one.
- Return to normal content and wait to see whether temporary image retention fades. Check the manufacturer pixel policy before attempting any remedy; pressure, rapid flashing and unapproved “fix” methods can damage the display.
What to check first
Use these checkpoints to keep the comparison focused. Record the visible behavior rather than assigning a fault label too early.
- Inspect black, white, red, green and blue
- Clean the surface before judging
- Check warranty terms before attempting remedies
How to read what you see
| Observation | What it can suggest | Useful next check |
|---|---|---|
| The point is black on every solid color | A non-emitting pixel or blocked light path is possible. | Confirm at native mode and consult the pixel/warranty policy. |
| The point stays one bright color | One or more subpixels may be stuck. | Document across several colors without pressing the panel. |
| The mark disappears after surface cleaning | It was debris rather than a panel pixel defect. | Use normal operation; no panel remedy is needed. |
Common mistakes to avoid
- Do not press, tap or massage the panel.
- Do not use rapid flashing patterns, especially around photosensitive users.
- Do not promise that software can repair a physical pixel.
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 point is black on every solid color”—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 screenshot capture a dead pixel?
No. A screenshot records the rendered image before the physical panel. A defect visible in a screenshot on another display is a rendering issue, not that panel pixel.
Is one bad pixel covered by warranty?
Policies vary by manufacturer, model, pixel type and location. Check the exact product terms.
Primary technical references
The following specifications define the browser APIs discussed in this guide. They are primary web-platform references, not product repair manuals.