LCD Dead Pixel Test

Sit at your normal viewing distance and run the full nine-colour cycle. Faulty pixels are single dots, so lean in only to confirm a suspect — scanning from too close makes every speck look suspicious.

Hide the controls with H to inspect the corners and edges, where backlight unevenness can mask a dot. On a laptop, keep the charger behaviour constant: some panels shift brightness on battery, which changes what you see.

Run the screen pixel test before paying: cycle all nine colours, inspect the corners, and save the text summary as your inspection note. A clean pass on every colour is a good sign, but this visual check cannot certify a used panel.

Ask the seller about the panel’s history — drops and pressure damage cause faults that only appear on some colours. Your saved summary records what you saw at purchase time.

Browsers only grant fullscreen after you interact with the page, which is why the test asks the moment you press Start Test. If the browser refuses, the test continues in a viewport-sized field and says so openly — the colours work the same.

Whether faulty pixels qualify for repair or replacement depends on the manufacturer’s pixel policy, which often tolerates a few defective pixels per panel. Look up the published policy and attach your inspection note as your record — it is not a warranty certificate by itself.