Condition & repair
Dead pixels, lines and burn-in — what they cost you
Cracked glass is obvious. The panel faults underneath it are the ones sellers miss — and buyers do not.
The three faults, and how to test for each
Dead pixels and spots
Dark patches that stay put whatever is on screen. Test with a plain white image at full brightness. A single pixel is hard to see; a cluster is graded as a spot, and several clusters as heavy spots.
Lines
A permanent vertical or horizontal column, usually coloured, caused by a failing display driver. Test on both white and black backgrounds. This is the most expensive of the three because it always means a panel replacement.
Burn-in and discolouration
A faint ghost of something that used to be on screen — the navigation bar, a keyboard, a status icon — or a colour cast across part of the panel. Overwhelmingly an AMOLED phenomenon, so it turns up on older Samsung, OnePlus, Vivo and Oppo handsets.
What they cost
| Fault | Typical deduction | Repairable economically? |
|---|---|---|
| 1–2 minor spots | Small | No |
| Three or more, or a large patch | Moderate | No |
| Permanent line(s) | High | No — panel replacement |
| Minor discolouration | Small | No |
| Major discolouration / burn-in | Moderate to high | No |
All sit inside the screen section cap, so they do not stack indefinitely.
Because they share a cap with glass damage, a phone with a cracked screen and burn-in is not penalised twice in full. That is worth knowing before you decide the phone is worthless.
Why repair is not the answer
Every one of these faults requires replacing the display assembly, which is the single most expensive component in the phone. Doing it through a local shop also makes the display non-original, which triggers its own larger deduction — the trap described in is a screen replacement worth it.
The exception, as always, is a repair covered by warranty or insurance.
Declare them precisely
Quote flows ask about spots, lines and discolouration as separate questions for a reason: a phone with one small spot is worth considerably more than a phone with a line down the middle, and a single "screen damaged" answer cannot express that.
Answer each one for what it is. Precision here works in your favour more often than not.
Testing a screen properly in two minutes
Most panel faults are invisible on a normal home screen and obvious on a flat colour. Two minutes with four images finds essentially everything a grader will find.
- Set brightness to maximum and turn off auto-brightness, night mode and any colour filter.
- Display white: reveals dead pixels, dark patches and dust under the glass.
- Display black: reveals stuck pixels, backlight bleed on LCD and uneven blacks on AMOLED.
- Display grey at around 50%: this is the one that exposes burn-in and tint, which white often hides.
- Display red, green and blue in turn: reveals a failing colour channel and single-colour lines.
Do it in a dim room, and hold the phone at arm's length as well as close up — burn-in in particular is easier to see from a distance than with your nose against the glass.
Frequently asked questions
- Does screen burn-in reduce resale value?
- Yes. It is graded as display discolouration, which is a defined deduction separate from cracked glass, and it is common on older AMOLED phones.
- How do I check for dead pixels?
- Display a plain white image at full brightness and look for dark patches that stay in place, then repeat on black to catch stuck pixels and backlight bleed.
- Is a line on the display fixable?
- Only by replacing the display assembly, which is rarely worth it before a sale — and a third-party panel triggers a larger deduction than the line itself.
- Do panel faults and cracked glass stack?
- They are graded separately but capped together within the screen section, so a phone with both is not penalised twice in full.
- What is the best way to test for screen burn-in?
- A flat grey image at about 50% brightness in a dim room, viewed from arm's length. Burn-in that is invisible on a white screen usually shows clearly on grey.