Question Difference between a stuck pixel, and a dead sub-pixel ?

[KingC12]

I have just bought a Samsung Odyssey G7 144hz 4k monitor, and have noticed it has a red pixel on when it's a dark background, black, navy blue, dark green etc (at least that's only when I notice it).

I have been trying all the usual techniques, that I know, such as leaving the monitor off for a couple hours, using the pixel refresher videos, and massaging the pixel. I know the difference between a dead pixel and a stuck pixel, through colouring.

But am I wasting my time, as I don't know how to tell if it's a dead subpixel for example?

TIA

 

[Lutfij]

Question - Stuck or dead pixel?

Hi, I am running an ASUS VG248QE, and I suddenly found that everytime I have some sort of dark colors on my screen, on pixel turns red and does not change, but when I go back to bright colors the pixel works fine. This means if I hover my cursor over it(while on a dark background), the red pixel...

forums.tomshardware.com

+
https://skylum.com/blog/stuck-pixel...ck pixel appears as,Rare or common phenomenon.

 

[KingC12]

Question - Stuck or dead pixel?

Hi, I am running an ASUS VG248QE, and I suddenly found that everytime I have some sort of dark colors on my screen, on pixel turns red and does not change, but when I go back to bright colors the pixel works fine. This means if I hover my cursor over it(while on a dark background), the red pixel...

forums.tomshardware.com

+
https://skylum.com/blog/stuck-pixel-vs-dead-pixel#:~:text=A stuck pixel appears as,Rare or common phenomenon.

Question - Stuck or dead pixel?

Hi, I am running an ASUS VG248QE, and I suddenly found that everytime I have some sort of dark colors on my screen, on pixel turns red and does not change, but when I go back to bright colors the pixel works fine. This means if I hover my cursor over it(while on a dark background), the red pixel...

forums.tomshardware.com

+
https://skylum.com/blog/stuck-pixel-vs-dead-pixel#:~:text=A stuck pixel appears as,Rare or common phenomenon.

Is there anyway of telling for sure if it's a dead subpixel though? Not the first time it's happened to me either I have a OLED LG tv at the moment with a green one. And I haven't been able to get rid of either.

 

[hotaru.hino]

If you've done everything you could to try to fix it, then it's a dead pixel.

 

[KingC12]

If you've done everything you could to try to fix it, then it's a dead pixel.

Even if it's red? This is the thing that confuses me. As I always thought if it was coloured it was stuck. But then people say it could be a dead subpixel, but I feel I must of been really unlucky for both blue and green subpixels to die simultaneously on a brand new monitor. But I'll be honest I don't know much about the inside workings of monitors.

 

[Glenwing]

Even if it's red? This is the thing that confuses me. As I always thought if it was coloured it was stuck. But then people say it could be a dead subpixel, but I feel I must of been really unlucky for both blue and green subpixels to die simultaneously on a brand new monitor. But I'll be honest I don't know much about the inside workings of monitors.

If it's colored on dark, then there's a stuck subpixel. If it's colored on white, then there's a dead subpixel.

 

[hotaru.hino]

Even if it's red? This is the thing that confuses me. As I always thought if it was coloured it was stuck. But then people say it could be a dead subpixel, but I feel I must of been really unlucky for both blue and green subpixels to die simultaneously on a brand new monitor. But I'll be honest I don't know much about the inside workings of monitors.

Yes, even if it's red. Consider the circuit for a pixel in a typical LCD display:

It's basically two capacitors hooked up to a transistor switch. One of the capacitors is the liquid crystal element itself, the other is a so-called storage capacitor that keeps the charge long enough for the pixel to retain its state until the next refresh cycle. If there's a defect in either, then the circuit isn't going to work correctly. My guess is the capacitor fails to a short circuit condition, meaning 0V across the liquid crystal element which keeps it stuck in one state. The liquid crystal element in a typical monitor lets all the light through in a 0V state (i.e., the LCD blocks light when given a voltage).

A stuck pixel would have trouble discharging the storage capacitor, so rapidly flashing colors across it varies the voltage, which I presume "shakes" the charge out. I don't really know the exact theory, but that's my guess.

 

[KingC12]

If it's colored on dark, then there's a stuck subpixel. If it's colored on white, then there's a dead subpixel.

It isn't lit on white (at least I can't see it on white), so hopefully it is just stuck, but I'm starting to think something's dead. I will keep trying and hope it goes away on it's own fingers crossed, but I'm not that lucky.

 

[KingC12]

Yes, even if it's red. Consider the circuit for a pixel in a typical LCD display:

It's basically two capacitors hooked up to a transistor switch. One of the capacitors is the liquid crystal element itself, the other is a so-called storage capacitor that keeps the charge long enough for the pixel to retain its state until the next refresh cycle. If there's a defect in either, then the circuit isn't going to work correctly. My guess is the capacitor fails to a short circuit condition, meaning 0V across the liquid crystal element which keeps it stuck in one state. The liquid crystal element in a typical monitor lets all the light through in a 0V state (i.e., the LCD blocks light when given a voltage).

A stuck pixel would have trouble discharging the storage capacitor, so rapidly flashing colors across it varies the voltage, which I presume "shakes" the charge out. I don't really know the exact theory, but that's my guess.

Thankyou for the detailed response. I presume something has died then, due to the positioning of the pixel it's in my bottom left it is just catching my eye at the moment. Give it a week or so I should hopefully forget it's there, or maybe it will disappear on it's own, I've heard stories of people not having luck with any of the workarounds, and then randomly weeks/months later it just fixes itself.

 

[Glenwing]

The liquid crystal element in a typical monitor lets all the light through in a 0V state (i.e., the LCD blocks light when given a voltage).

That may be true for a calculator or old school digital watch, where voltage is applied to darken the segments, but active-matrix TFT displays used in monitors are the opposite. They fade to black (actually, grey-ish) when they lose charge. That's why driving an LCD monitor with too low of a refresh rate will result in black flickering when the capacitors aren't being refreshed in time, not white flickering. Or why monitors with a damaged or defective column driver gets black vertical stripes on some parts of the screen, not white vertical stripes.

It isn't lit on white (at least I can't see it on white), so hopefully it is just stuck, but I'm starting to think something's dead. I will keep trying and hope it goes away on it's own fingers crossed, but I'm not that lucky.

It is lit on white. White is produced by red, green, and blue all combining together. So when you show white, all 3 turn on. That's why stuck pixels (pixels that are stuck in the on-state) don't show up on white, because they're supposed to be on anyway.

This is unlike a dead subpixel, which will stay unlit. So if you had a dead red subpixel and tried to display white, that pixel would show up as cyan, because the blue and green would both turn on, but the red primary would be missing, so you'd get cyan instead of white.

White means all pixels on. So if there's a dead subpixel (one that doesn't turn on), it will show up as some color, because that pixel won't be able to produce white as it's missing a primary. Black means all pixels off. So if there's a stuck pixel (one that doesn't turn off), it will show up as a color because that pixel won't be able to produce black, as one of the primaries will be unable to turn off.

 

[beyondlogic]

I have just bought a Samsung Odyssey G7 144hz 4k monitor, and have noticed it has a red pixel on when it's a dark background, black, navy blue, dark green etc (at least that's only when I notice it).

I have been trying all the usual techniques, that I know, such as leaving the monitor off for a couple hours, using the pixel refresher videos, and massaging the pixel. I know the difference between a dead pixel and a stuck pixel, through colouring.

But am I wasting my time, as I don't know how to tell if it's a dead subpixel for example?

TIA

Idea to try remove power cable hold power button for a minute this completely discharges the monitor this can be done with TV do not use remote when repowering TV should be a toggle power switch by TV. Sometimes this method works others is massage with eraser using pressure.

 

[KingC12]

Okay so this is confusing me a bit more now. I definitely think something is dead now. Basically it's red on every single background, blue, green, black etc but if I leave a full blue background it eventually turns blue, but then will turn red again.

The weird part is that on red it displays black, how can this be? It displays red on every other colour except white which displays normal, but on red it displays black?