How to check for dead pixels
- Wipe your screen with a dry microfibre cloth first, so dust isn't mistaken for a fault.
- Press Start full-screen test. The screen fills with red.
- Look over the whole screen slowly, section by section, from close up.
- Click, or press the right arrow or Space, to move through green, blue, white, black and grey. The left arrow goes back. Press Esc to finish.
Dead pixel or stuck pixel?
- A dead pixel stays dark on every colour, most obvious on white. The pixel isn't getting power, and it usually can't be fixed.
- A stuck pixel stays one colour (red, green, blue or a mix) whatever is on screen, most obvious on black. Stuck pixels can sometimes be freed.
- A dot that moves when you wipe the screen is dust; one that's there on every colour but blurry may be dirt inside the screen layers.
Trying the stuck pixel fixer
The fixer flashes a small square through bright colours very quickly. Placed over a stuck pixel, the rapid changes can sometimes unstick it. Drag the square over the faulty pixel and leave it running for 10 to 20 minutes, then check again. It doesn't work on dead pixels, and there's no guarantee, but it's harmless to try.
Motion and refresh rate test
The motion test slides a block across the screen and measures how often your browser draws a new frame, which normally matches your display's refresh rate: 60 Hz for most screens, 120 Hz or more for gaming monitors and newer phones. If you've paid for a high-refresh monitor but see 60 Hz, check that the refresh rate is set correctly in your display settings, and that your cable supports it (DisplayPort or a recent HDMI cable). Watch the block for smearing or ghosting trails too, which show slow pixel response.
Is a dead pixel covered by warranty?
It depends on the maker. Many have a "pixel policy" that only replaces a screen once there are several faulty pixels, or one in the middle of the screen. If you find one on a new screen, contact the seller while you're still in the returns period.