Tools
Dead pixel test
Step through solid colours in full screen. Any dot that doesn't match is a pixel fault.
How the test works
Solid colours
Black, white, red, green, blue, cyan, magenta, yellow and grey fill the screen one at a time.
What to look for
A dot that stays black is dead. A dot that stays red, green, blue or white is stuck. Wipe the screen first: dust looks like a pixel fault.
Stuck pixel fixer
Rapidly cycles colours in a small box you can move over the stuck pixel. It flashes, so it's behind a photosensitivity warning and never starts by itself.
Questions
What's the difference between a dead and a stuck pixel?
A dead pixel gets no power and stays black. A stuck pixel has one or more sub-pixels permanently on, so it shows a fixed colour. Stuck pixels can sometimes be revived.
Is a dead pixel covered by warranty?
It depends on the manufacturer's pixel policy, which often requires a minimum number of faults. Check your warranty terms.