Buying a Used TV or Monitor: Screen Tests You Can Do in Ten Minutes

Before you go: what to carry

• A pen drive or phone with these files saved: a plain white image, a plain black image, plain red, green and blue images, a grey gradient image, and a video with fast movement (a cricket match or action scene).
• A laptop or phone with a cable adapter, if you are buying a monitor.
• A small torch, to inspect the back ports and the screen at an angle.
• Your own HDMI cable, in case the seller's cable is part of the problem.

The ten-minute test, in order

• Minute 1: Look at it switched off. Hold the screen under good light and look for scratches, cracks, pressure marks, yellow patches or a bent frame. Check that the stand or wall bracket mount is complete.
• Minute 2: Switch on and wait. Note how long it takes to start. A very long start-up, repeated restarts or a clicking sound from the speakers are warning signs.
• Minute 3: White screen. Display the plain white image. Look for yellow or pink tints, dark patches, vertical or horizontal lines, and uneven brightness at corners.
• Minute 4: Black screen in a dim room. Dim the lights or shade the screen. Light leaking from the edges or corners (backlight bleed) is easier to see now. A little may be normal in some panels, but strong patches are a concern.
• Minute 5: Red, green and blue screens. Look closely for dead pixels (tiny dots that stay dark or stuck in one colour). A single dot in a corner may be tolerable to you; several or a cluster is not.
• Minute 6: Gradient. Look for visible bands or colour shifts, which can show a panel or processing problem.
• Minute 7: Motion test. Play the fast video. Watch for blur, flicker, stuttering or lines when the picture moves. Look at it from the side as well; colour changing sharply at slight angles is common in some panels but strong changes should affect your price.
• Minute 8: Ghost images and burn-in. On a static image such as a menu or a logo, look for faint outlines of earlier images that remain when the screen changes. Burn-in is more commonly discussed for some screen types, but any persistent shadow is a reason to ask questions.
• Minute 9: Ports, remote and sound. Plug in HDMI and USB, test each port you need, switch inputs, and try the remote or buttons for volume, menu and power. Play sound at several volumes and listen for crackling.
• Minute 10: Settings and software. For a smart TV, check that it connects to Wi-Fi, opens the apps you use and has not been locked to an account you cannot remove. Perform a factory reset if the seller agrees, so the previous owner's accounts are gone.

Quick reference table

• Dead or stuck pixels — What you will see: Tiny constant dots; What to do: Count them; reject or negotiate
• Backlight bleed — What you will see: Bright patches on a black screen; What to do: Reject if strong
• Vertical or horizontal lines — What you will see: Lines on all test images; What to do: Reject, since repair cost can be high
• Burn-in — What you will see: Faint persistent shadow; What to do: Reject or price down heavily
• Flicker — What you will see: Screen blinking at normal use; What to do: Reject or have it checked
• Dead port — What you will see: Input not detected; What to do: Check if you need that port
• Crackling speaker — What you will see: Noise at medium volume; What to do: Negotiate; check if a speaker or board is at fault

Price and paperwork

• Compare three listings of the same screen size and approximate age. Ask for the original bill or warranty card if it exists, and check the model number on the sticker at the back against the seller's claims. Ask about the repair history and who repaired it. A screen replacement or panel repair can cost a large part of a unit's value, so a hidden panel problem should reduce your offer sharply. We do not quote prices here as they depend on model, size and city.

Handover and transport

• Protect the screen with a cloth and, ideally, the original box and foam. Never carry a TV flat on its back, and keep pressure off the panel. Keep the remote, stand, screws and cables together and note them in your receipt.

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• Post your item free

Safety tips

• Meet in a public, well-lit place and, where possible, take someone with you.
• Inspect the item before you pay and check it matches the listing.
• Never pay in advance, share OTPs, or move payment outside the agreed meeting.
• Keep contact through the listing page — contact details are privacy-gated in the app.
• Report suspicious sellers instead of continuing the conversation.

Frequently asked questions

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