Dead pixels - What causes them

[J90RDN]

I have a brand new Pioneer PDP LX 5090 which I wall mounted and started using 2 weeks ago. Within a couple of days whilst cleaning the frame whilst the TV was on I noticed 3 dead pixels, 2 intermitant and 1 permanent (like little red crosses). Spoke to Pioneer who have said that if they are still there in a month's time they will replace the screen (not the whole TV, just the panel I assume). I spoke in length with the Pioneer guy on the phone who sounded like he knew what he was talking about, and one of the questions I asked him was the likelyhood of any other dead pixels appearing. He assured me it was highly unlikely for any more to appear once the screen was in use.

Long story short (!) I've been checking every day for more dead un's, and sure enough last night I noticed 2 more, making a total of 5, and they are dotted randomly all over the screen, not just in one area.

I've checked my setup and everything is present and correct, so I'm sure it's not something I'm doing. Onkyo 606 amp, Pioneer 51 Blu Ray, Amstrad Sky+ box.

Question is, what causes the dead pixels, and have I just got a duff one? For a 2 grand screen I wouldn't expect this!!

[Medrep1]

I had a brand new LX508 and a two pixels died within 6 weeks of getting it. To cut a long story short, Pioneer told me (not directly, 3rd part engineers on behalf of pioneer) that they would not replace anything.

I went nuts, and if it wasnt for the relationship with my dealer, I wouldnt have a 5090 now. They (audio ex) replaced the screen for me to the new 5090, inc corresponding speakers and stand.

I was disgusted at pioneer, and their afterservice. Audio Ex I cannot fault and still to this day spend ££££'s with them for this reason, and never buy 'cheaper' online. IMO its just not worth it.

I was told that pixels dying are natural of plasma technology, and that unless (i forget how many) so many pixels die within a square inch of the screen then it is not classed as a fault

I dont know why they die, but I do know you are lucky to have been offered a repair. They will be there in a month, so dont take any crap, and get that offer from them in writing. Get it done asap, and make sure all your warranties are up to date afterwards.

Sorry to hear, I feel for you because I went through the same thing

[J90RDN]

Yeah, dead pixels sunddenly springing into life doesn't sound likely does it, but I'll do what they say and wait a month. Haven't got it in writing unfortunately, but I do have the guys name and will hound Pioneer until they resolve it (hopefully it won't come to this). Just don't understand why it should happen to such an expensive screen? It sounds silly but from 2 meters I can now see the dead pixels when the screen is lighter because I know where they are, and when a white screen comes on the TV I automatically look to see if I can spot them Wrong I know, but human nature!!!!

[mbell]

They can die because it's virtually impossible to build millions of pixels onto a screen and *guarantee* that they will all work for the lifetime of the panel.

Panels are expensive things to produce and the manufacturers figure that a stuck pixel here or there should be acceptable as it probably won't interfere with the viewing experience. Some people report that they have happily used a TV for a long time and it's only when they've gone on a pixel hunt that they've found stuck pixels.

Having said that, it would annoy the hell out of me to even know that there's a duff pixel somewhere on the screen.

If you can easily demonstrate that stuck pixels are detrimentally affecting your viewing experience (for example, they are bunched together or near the centre of the screen) or kick up enough fuss, you should be able to get a replacement.

Me? If that got me nowhere, I'd try to find a way of killing off a few more so that the situation becomes obvious! Anyone know of a gadget that could do that?

[barrybarwick]

Originally Posted by mbell

Me? If that got me nowhere, I'd try to find a way of killing off a few more so that the situation becomes obvious! Anyone know of a gadget that could do that?

Hammer!!!

[joffahall]

dead/stuck pixels are actually a fault that is caused during the manufacturing process of the panel.

dead pixel (black/dark pixels on a white/light screen) are usually caused by a transistor in the transparent electrode layer that is stuck "on." It continuously runs a charge across the liquid crystal material, so no light ever passes through to the RGB layer.


stuck pixels (white on a black/dark background) is a bright dot defect is a group of three sub-pixels (one pixel) all of whose transistors are not working. This allows all light to pass through to the RGB layer, creating a bright white pixel that is always on.

sub pixel faults (displaying red, green or blue) are a defect is a manufacturing defect in which the RGB film layer was not cut properly.


all companies have different ways of dealing with the issue of stuck/dead pixels but either way its a fault. most companies usually have a disclaimer in the manual (so have a read) to explain on of 3 things

1. dead stuck pixels do not constitute a fault (unless its really excessive and in clusters all over the panel) and usually the company will replace the tv/panel as a gesture of goodwill.

2. the manual will state how many defective pixels constitute and if you have an issue to contact the manufacturer.

3. zero tolerance for defective pixels and if you spot 1 then arrange a replacement.

manufacturers that offer a zero tolerances are very few (Samsung in Asia and japan are the only ones that i can think of) and their tv`s usually cost a fortune.

either way defective pixels are pretty common but mainly only noticable if you go looking for them. i had 3 replacement Sharp tv`s due to other issues and every one that came in the house by the delivery people had defective pixels on them so its not just you.

also im pretty suprised that Pioneer offered to replace the panel with for 5 defective pixles unless they were in a cluster on the screen.

[D'@ve]

Originally Posted by joffahall

2. the manual will state how many defective pixels constitute and if you have an issue to contact the manufacturer.

Panasonic TH42PX80 plasma manual says:

Permanently lit spots on screen
• Due to production process involved in this technology this may result in some pixels which are permanently lit or unlit. This is not a malfunction.

This is plainly a stupid thing to say. If "some" pixels (say 50) go dead on my screen, it's a malfunction - no argument. I'll undoubtedly be able to get the retailer under the Sale of Goods Act (not fit for purpose), whatever the manufacturer says. If they'd specified say "5 spread widely across the screen" or "3 in a single cluster" that would be more reasonable but stating "some" is ludicrous.

They really do need to state how many and where, so we the consumers know where we are before buying the goods (like Insurance companies do with windscreen chips). I think their very vagueness might even work against them in a Court case but as my claim would be with the retailer not Panasonic, it doesn't really bother me.

[alsina]

Originally Posted by D'@ve

Panasonic TH42PX80 plasma manual says:

Permanently lit spots on screen
• Due to production process involved in this technology this may result in some pixels which are permanently lit or unlit. This is not a malfunction.

This is plainly a stupid thing to say. If "some" pixels (say 50) go dead on my screen, it's a malfunction - no argument. I'll undoubtedly be able to get the retailer under the Sale of Goods Act (not fit for purpose), whatever the manufacturer says. If they'd specified say "5 spread widely across the screen" or "3 in a single cluster" that would be more reasonable but stating "some" is ludicrous.

They really do need to state how many and where, so we the consumers know where we are before buying the goods (like Insurance companies do with windscreen chips). I think their very vagueness might even work against them in a Court case but as my claim would be with the retailer not Panasonic, it doesn't really bother me.

Presumably you have a tv with defective pixels? How many are there and where abouts on the screen?

[D'@ve]

Originally Posted by alsina

Presumably you have a tv with defective pixels? How many are there and where abouts on the screen?

No but before I bought the set I did think a lot about what I'd do if I had this problem, and what to advise my daughter who has a simiilar set. Panasonic's vagueness just made it more difficult to decide what to do - in the end I decided that the manufacturer doesn't matter too much as it's unlikely I'd be claiming from them, and in the end they wouldn't be deciding if it's fit for purpose or not.

[joffahall]

Originally Posted by D'@ve

Panasonic TH42PX80 plasma manual says:

Permanently lit spots on screen
• Due to production process involved in this technology this may result in some pixels which are permanently lit or unlit. This is not a malfunction.

This is plainly a stupid thing to say. If "some" pixels (say 50) go dead on my screen, it's a malfunction - no argument. I'll undoubtedly be able to get the retailer under the Sale of Goods Act (not fit for purpose), whatever the manufacturer says. If they'd specified say "5 spread widely across the screen" or "3 in a single cluster" that would be more reasonable but stating "some" is ludicrous.

They really do need to state how many and where, so we the consumers know where we are before buying the goods (like Insurance companies do with windscreen chips). I think their very vagueness might even work against them in a Court case but as my claim would be with the retailer not Panasonic, it doesn't really bother me.

the manual says permanently lit or dark SPOTS. the manual DOES NOT SAY permanently lit areas or patches.
use some common sense we all know a pixel is about the size of a pin head and even if defective can not be seen under normal viewing.

if there are a few dots scattered about that do not effect normal viewing then there is no fault.

if there is areas or patches that are clearly seen under normal viewing then its a fault its as simple as that.

[alsina]

Originally Posted by D'@ve

No but before I bought the set I did think a lot about what I'd do if I had this problem, and what to advise my daughter who has a simiilar set. Panasonic's vagueness just made it more difficult to decide what to do - in the end I decided that the manufacturer doesn't matter too much as it's unlikely I'd be claiming from them, and in the end they wouldn't be deciding if it's fit for purpose or not.

Correct, Panasonic would have no say in the outcome. But these things are (ultimately) decided by a court of law who would refer to specialists in the field i.e. engineers. I can't see many engineers producing a report to confirm that a fault-free screen is the norm. They would usually refer to ISO-13406-2 (or similar) which is an industry standard which acts as a guideline for this issue. Claiming that a tv is not fit for purpose because of a few defective pixels would be almost impossible if it ended up in the small claims court. In cases like this, the court uses a 'common-sense' approach unless of course the retailer has specifically stated that every pixel on the screen will be fully working.