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Dead/stuck pixels more likely if?

azz

Established Member
Hi does anyone know if the above is more likely with lcd or plasma?

In my experience it is more likely with lcd but does anyone have a definitive answer.


azz
 
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blackeyepurple

Guest
Got through 9 lcd's (1x Tosh 27WL56 1x Samsung 26" 3x Sharp 26" and 4x Tosh 32WL56) and 5 of those had between 1 and 6 dead/stuck pixels depending on model manufacturer. Was not happy with LCD due to poor blacks and viewing angle etc. Moved on to plasma with an increased budget....had 3 Panasonic PHD8's plasma's and 2 of those had dead pixels (the perfect fault free set died) and I now have a Pioneer 436FDE plasma with no duff pixels or other probs. So to sum up.....both technologies suffer pixel failures.....its the luck of the draw.
 

pixelated

Established Member
Well both are prone to dead pixels but I always get the impression they're more common LCDs. But Plasmas get them too.
 

pixelated

Established Member
blackeyepurple said:
Got through 9 lcd's (1x Tosh 27WL56 1x Samsung 26" 3x Sharp 26" and 4x Tosh 32WL56) and 5 of those had between 1 and 6 dead/stuck pixels depending on model manufacturer. Was not happy with LCD

That's an unfortunate series of TVs!
 
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blackeyepurple

Guest
Stuart Kirby said:
That's an unfortunate series of TVs!

Indeed.....I'm cursed when it comes to technology! I just kept plugging away with returning products I wasn't happy with until I was.....budget went from £600 to £2,200 though! I'm sure there are a couple of web based companys that would shudder if they heard my name....thank god for 7 day returns for any reason on web sales!
 

cooperda

Prominent Member
azz said:
Hi does anyone know if the above is more likely with lcd or plasma?

In my experience it is more likely with lcd but does anyone have a definitive answer.

azz

I would have thought the simple rule would be - the bigger the screen the more likely faulty pixels - so since plasmas are usually larger screens they are more likely to have stuck pixels.

If you are talking of two screens of the same size then the next most likely difference to my mind would be the reputation of the brand - in sourcing their TVs with Class A screens.

Cheers, Dave C.
 
4

4th Horseman

Guest
I can top that!
8 LCDs, 4 different brands, all had dead/stuck pixels, going from 1 to 9!
Never had one without a flaw. I live with the one with one stuck subpixel now, well...
 

pixelated

Established Member
cooperda said:
I would have thought the simple rule would be - the bigger the screen the more likely faulty pixels - so since plasmas are usually larger screens they are more likely to have stuck pixels.
Cheers, Dave C.


Remember a 37 inch LCD will have more pixels generally than a 37 inch Plasma...
 
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blackeyepurple

Guest
4th Horseman said:
I can top that!
8 LCDs, 4 different brands, all had dead/stuck pixels, going from 1 to 9!
Never had one without a flaw. I live with the one with one stuck subpixel now, well...

Well I guess if you still have a dud pixel then i'm the overall winner.....lol....:rotfl:
 

M271

Standard Member
With regard to LCD screens

Do dead/stuck pixels come and go or once stuck do they remain so for ever ?
I've heard of Pixel fixer discs to play through the screen and to gently rub the malfunctioning LCD pixel, has this ever worked for anyone?

Do more pixels fail over time or do they just work or not from the beginning ? or do you and up with say 5 extra per year as they fail ?
 

pixelated

Established Member
Dead pixels can develop, they don't necessarily have to be there the first time you turn your TV on. More pixels can potentially fail, but it's like that with any LCD or Plasma really - just because you have one doesn't automatically mean others will become stuck or die :)

It is possible for a dead pixel to recover, some have success by gently rubbing the area of the screen where the pixel in question is, or as you mentioned, a pixel fixer, I don't know how successful those fixers are though.
 

LV426

Administrator
Staff member
There's another factor, too. On a LCD a pixel is more likely to fail bright, whereas on a Plasma it's more likely to fail dark. And a bright failure (especially a green one) is more visible/obtrusive than a dark failure. LCD pixels are much more likely to fail when new (i.e. DOA) than they are to fail during use.

But, if we're doing statistics:

- 22 inch Samsung LCD TV (1280x720)
- (old) 15 inch Sharp LCD monitor (1024x768)
- (new) 17 inch OEM LCD monitor (1280x1024)
- several mobile phones and DECT phones with LCD screens
- digital camera with an LCD screen
- portable DVD with LCD screen

all pixel perfect and all the first one bought (i.e. not replaced for any reason including bad pixels).

And an LCD RearPro TV, not the first bought, but replaced several times for reasons other than pixel failure - pixel perfect.

And an LCD projector (1366x768) with one failed - invisible from normnal viewing distance even if you know where to look.

Most of these things have had several hundered or thousand hours' use and none has changed in this respect since new.
 
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blackeyepurple

Guest
M271 said:
I've never noticed a dead/stuck pixel on a Lap Top Computer screen though !!

Same here....had 5 laptops over the last 6 years and no pixel faults at all.
 

Mr Sparkle

Standard Member
cooperda said:
I would have thought the simple rule would be - the bigger the screen the more likely faulty pixels - so since plasmas are usually larger screens they are more likely to have stuck pixels.

If you are talking of two screens of the same size then the next most likely difference to my mind would be the reputation of the brand - in sourcing their TVs with Class A screens.


With regard to LCDs, generally, it is more likely to expect pixel defects/failures on smaller TV screen sizes. Why ? for example with a resolution of say 1366 x 768, a 20" panel is likely to have a smaller transistor (TFT - thin film transistor) geometry than a 40" panel ie the pixels are larger on a 40" display and the production yield (from the TFT production line) is likely to be higher for the 40" than that of a smaller 17~20" panel with the same resolution. Obviously both 20" and 40" have the same number of pixels eg. 1366 x 768 = 1049088 x 3 (RGB) = 3147264 total transistors. Any manufacturing defect or failure of any of these 3+ million pixels is therefore not desireable!

In terms of 'quality' typically a Japanese or Korean TFT manufacturer will supply it's own domestic TV makers with Class 'A' product. Class 'B' quite often comes in Europe or the US for the use of local eruo TV makers ie Vestel in Turkey, who will make product under license for the big brands and also lesser known brands. Finally Class C is typically 'dumped' into China and Aisa and used by 'no name' brands.

The classification of product 'Class' is generally determined by a number of measurable factors: Brightness Uniformity, Contrast Uniformity and Pixel defects etc.

Plasmas are entirely different.

Hope this helps.

Mr Sparkle
 

M271

Standard Member
Interestingly I visited a company in the US who assemble In car DVD/Screen sets, they specify to their Japanese LCD panel manufacturer that they will not accept any dead pixels. Due the smaller nature of the screens several are cut from a much larger panels, apparently the good ones go to Japanese and US companies and the ones with some duff pixels go to Korean or Chinese screen assemblers !! don't know how true it is though. Just sales patter ?
 

Mr Sparkle

Standard Member
M271 said:
Interestingly I visited a company in the US who assemble In car DVD/Screen sets, they specify to their Japanese LCD panel manufacturer that they will not accept any dead pixels. Due the smaller nature of the screens several are cut from a much larger panels, apparently the good ones go to Japanese and US companies and the ones with some duff pixels go to Korean or Chinese screen assemblers !! don't know how true it is though. Just sales patter ?

Yes, this is true.

TFTs are made in a similar way to silicon chips. ie on a large wafer or substrate. TFT motherglass substrates are now in excess of 2m x 3m for 6th and 7th generation production equipment. Following the photo etching process (which determines the size of TFT that can be produced from the substrate) the substrates are then cut up into the individual glass size this may be 10.4", 15.4", 19", 26", 32" , 40" etc.. Defective pixels cannot be determined until the TFT glass cell is assembed into a complete TFT display module with drivers, backlight, bezel etc. and then tested (powered up).

Naturally enough more and more product manufacturers are requesting zero pixel defects.

Mr Sparkle
 

andrewfee

Prominent Member
As has been said, LCDs are more likely to suffer from dead/stuck pixels when compared to plasma, but are typically going to either show up DOA or in the first week or so. With plasma, it is less likely to have them, but they are more likely to develop over time.

However, LCDs are much higher resolution than the majority of plasma displays, and typically at smaller screen sizes. This means that dead/stuck pixels should be much smaller, and at "proper" viewing distances for SD content (3x the diagonal of the screen) should not be visible.
 

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