How many Dead/Stuck Pixels is the norm?

[sgupta]

Hey all,

How many dead/stuck pixels is normal on an LCD RP HDTV (Sony KDF-50WE655)? I unfortunately noticed one when close to the TV messing with my DVD player (I had been trying not to look...honest.) So after that, I just looked to see if there were more, and I found four (1 green, 1 red, and two black [one appears smaller than the rest, which is odd]).

They're not visible from a normal viewing distance during normal viewing unless looked for and even hard to pick out if I look for 'em. The green one is most visible and the only one that can be if I really look hard. I'm a little annoyed they're there, but knew there would likely be a few. I'm just wondering if four is a reasonable amount.

Thanks. =o)

UPDATE:
Some interesting info.

Contacted Sony support to inquire about this, the norm, etc., and got a very nice guy:

Basically, he said Sony's policy used to be 6-8 pixels warranted replacement.

However, they were finding a lot of the time, trying to fix it or replace it (I think he said the imaging block, whatever that is) just made things worse (more of them, some in worse spots, etc.). So, they changed the policy to no longer give a number warranting replacement and instead only suggest it if the picture is fairly severely obscured. He said customers generally ended up more agitated and problematic when they were replacing them.

He recommended to just ignore it if it's not getting in the way of viewing, as trying to fix it would just make it worse.

He also said some had many more than 4. He's talked to people with 10 or so. And he said 4 seems reasonable and a fairly normal amount.

So I'm going to work on forgetting about it and not letting it get in the way of my viewing. lol. But I'd still like to hear some feedback.

 

[StevenD]

Samsung recently changed their warranty to read that they will replace/repair an LCD for ANY dead pixels.

 

[sgupta]

Thanks for the reply. I had heard about that - wish more manufacturers had that policy. Sony unfortunately as noted above does not.

 

[toto]

Sharp does pixel mapping. I asked Sony about pixel mapping and they said that was a Sharp exclusive.

 

[sgupta]

Pixel mapping? Not familiar with the term.

 

[TyroneShoes]

Sharp does pixel mapping. I asked Sony about pixel mapping and they said that was a Sharp exclusive.

Maybe as a policy on consumer gear. Ironically, Sony has been doing it on their pro cameras for many years. It involves identifying a dead/stuck pixel, and addressing it with the data from an adjacent pixel, which all but makes it invisible. This is likely not something that can be done in the field, and mostly it is done in manufacturing to allow substandard imaging blocks to still be used. I can't imagine it being a practical solution after the sale. If that is the case, that means that manufacturers that map pixels in manufacturing have lower tolerances than those who do not (they reject them instead). Bottom line, check your new set carefully, before the grace period runs out. If it already has, there's no reason to go looking for trouble.

 

[TyroneShoes]

Sharp does pixel mapping. I asked Sony about pixel mapping and they said that was a Sharp exclusive.

Maybe as a policy on consumer gear. Ironically, Sony has been doing it on their pro cameras for many years. It involves identifying a dead/stuck pixel, and addressing it with the data from an adjacent pixel, which all but makes it invisible. This is likely not something that can be done in the field, and mostly it is done in manufacturing to allow substandard imaging blocks to still be used. I can't imagine it being a practical solution after the sale. If that is the case, that means that manufacturers that map pixels in manufacturing have lower tolerances than those who do not (they reject them instead). Bottom line, check your new set carefully, before the grace period runs out. If it already has, there's no reason to go looking for trouble.

BTW, the norm is zero. It's only because they are easy to miss and some of us have let the manufacturers slide that there are sets out there with more than zero.

 

[RobbinM]

Stuck Pixels are normal

I've read a bunch of stuff over at the RP forum in avsforum.com and I don't think I've ever seen anyone claim to have a zero stuck pixel LCD RP. Myself, I have 3. And I literally have to be less than a foot away to see them. I've read of owners of Panasonic that had 20-30.

I would say that the black pixels are dust or something like that. For a pixel to be black on a three panel lcd set, the same pixel must have failed in the same way on all three panels -- the odds of that are very low.

The usual advice is if you can't see the pixels from normal viewing distances, I wouldn't worry about it. They replace the entire light engine in these sets when they are repaired. And the new engine will have it's own stuck pixels. It's the nature of LCD technology apparently.

Robbin

 

[sgupta]

Pixel mapping sounds very interesting. It'd be a cool technology to see in future sets to reduce this problem if it could be well-implemented, though I'd agree it should be no excuse at all for substandard screens.

I would agree that most people I've talked to have at least 1 or 2 (and Sony said 4 wasn't an unusually high number). That and the Sony response (which basically said what you're saying Robbin), not to mention me really not being able to notice it (unless I really, REALLY look for it and note where it is) from a normal viewing distance, has me where I'm just going to accept it and enjoy the set and try to forget about this. I think eventually we will be at a point where there are 0 pixels like this, and I commend Samsung for having a 0-dead-pixel policy and hope more retailers pick up with this in the future. But for now, I think I'll just enjoy my set.

As far as the black pixels, I think one of them (one appears smaller) may indeed be dust. The other, I don't know. Could just be dead instead of stuck or perhaps more dust or maybe it's just a dark color similar to black.

At any rate, thanks much for the feedback!

 

[Stargazer]

The more pixels they put into these television sets the smaller each pixel will be resulting in each pixel being even less noticable. The next step above HD would probably have a lot less noticable dead pixels even if the same percentage of pixels goes out on the screen as the current models because each pixel that goes dead would take up less of an area. That in combination with pixel mapping would probably solve the issue with dead pixels showing up. If the future HD tv's had 2-3 times the number of pixels then it would take 2-3 pixels next to each other to get the same visual effect of 1 dead pixel in today's HD television which would be less likely with pixel mapping.

This technology just keeps getting better and better.

 

[RichardF]

As a service center I find this varies from one manufacturer to another. I have seen perfect pixel responses. Oddly on one it developed a bad pixel 60 days after changing out the light engine.

Bear in mind this applies to LCD and LCOS only and is not a problem with DLP.

Your best bet is when you get the display pop in a calibration DVD and put up the red, green, blue, white and black full fields to find out how many you have.