Buying a Used Monitor This Sale Season? The 5-Minute Test Checklist
Quick answer: With OLED and high-refresh prices dropping through 2026, used and open-box monitors are excellent value — but only if you test them before you pay. Five minutes of checks catches the faults that are expensive or impossible to fix later. Start with the dead pixel test and the refresh rate test.
1. Dead and stuck pixels
Fill the screen with solid black, white, red, green and blue and scan for dots that don't match. Dead pixels stay black; stuck pixels glow a color. A single edge pixel is easy to live with; several, or one in the center, is a walk-away.
2. Backlight bleed and uniformity
On a black screen in a dim room, look for bright patches around the edges — a little is normal on LCD, a lot is not. On a solid gray screen, check for blotches or color tints across the panel.
3. Refresh rate and resolution
Confirm the panel actually hits its rated refresh with the refresh rate test, and that it is running at its native resolution so text looks crisp. On fast panels, remember the right cable is needed to reach high refresh.
4. Motion, burn-in and ports
Drag a window quickly to spot heavy ghosting. On an OLED, view solid colors and static desktop elements to catch burn-in or retention. Then test every input port and the stand, since a wobbly stand or dead HDMI port is easy to miss in a quick look.
Do it before money changes hands
Running the dead pixel test and refresh rate test on the spot gives you grounds to negotiate or walk away. Our complete guide on testing a new monitor covers the used-buyer extras in full.
Sources: VESA — DisplayPort · Microsoft — View display settings in Windows
Frequently asked questions
What should I test first on a used monitor?
Dead and stuck pixels. Fill the screen with solid black, white, red, green and blue and scan for dots that do not match — dead pixels stay black and stuck pixels glow a colour.
How much backlight bleed is normal?
A little around the edges is normal on an LCD panel; a lot is not. Check on a black screen in a dim room, and use a solid grey screen to spot blotches or colour tints.
Is one dead pixel a reason to walk away?
A single pixel at the edge is easy to live with. Several, or one in the centre of the screen, is a walk-away.
What do buyers usually miss?
The physical checks. Test every input port and the stand, since a wobbly stand or a dead HDMI port is easy to overlook in a quick look — and on an OLED, view solid colours and static desktop elements to catch burn-in.