kdl-40v3000 bravia dark lines/shadows.

[nishmalek]

i have exactly the same problem as the other people who have written about this tv model on the forum and there seems to be manty many more out thereon forums reporting the same problem that sony will not acknowledge.

there are dark lines running down my screen and a dark shadow line about an inch think on the right hand side of my screen, this was more noticable when watching football. my tv is not under warrranty anymore but is only 2 and a 1/2 years old. it seems that sony have created their screens to only last this long as lots of people have the same complaint.

i have just rang sony and i have been told that "there is no known problems with this model" that is rubbish as clearly there are a few of us just on this forum with the same pronblem. So we are paying about £1000 for a tv that will only last 2.5 years. i am disgusted with the lack of help and support from the sony call centre staff who basically said i need to get it fixed myself and i need to book it in with a service engineer. I suspect this is a problem with the panel or with the screen where a replace ment would cost you more than getting a new set. it would cost me £45 just for someone to come out and tell me that without even having it repaired. as a dedicated sony buyer over the years i cannot believe that my most expensive buy has only lasted 2.5 years.

WHY IS SONY NOT DOING ANYTHING ABOUT THIS PROBLEM??

[durrydave]

Hi virginreco,

Can you believe I only discovered that these dark lines were a common issue this week. I also only found out this week about the "overheating" recall on this model TV and a few others, I am a Which Mag member and discovered a forum there about the recall and also the dark shadows issue.

I am waiting for a service engineer to call and arrange a visit to check out the overheating problem, I will use the opportunity to see what Sony will do about the dark shadows and show the engineer this forum.

Sony have to honour this as a product failure at some point.  Good idea about starting up a list. This fault must be Europe or even Worldwide. Can we check that out in some way, maybe Sony are recognising the issue in other countries??.

Shadows don't look so dark on my TV. Bought the TV in Feb 2008. Shadows started to appear early 2011, thought the screen was dusty to start with.

This totally spoils the viewing pleasure which was fantastic until this appeared. Will keep viewing this forum for further details and will advise outcome of service engineer visit.

[virginreco]

We bought ours in Dec 2007 and the shadowing began about Feb 2011. We have no kids so the TV is only on for about 3hrs per night and perhaps a bit more at weekends. Light useage I would say.

We thought it was dust at first too, one of the reasons for not getting in touch with Sony.

Our screen looked more like your one in the begining and has slowly got worse.

I learnt about the overheating issues last week, and have had an engineer round to check it out. It was while on Sony's website that I discovered that we are far from being alone with this manafacturing fault. I have today been in touch with Sony and have started the ball rolling, I just hope that it isn't a big hill.

[skipton01]

I've been doing some more research and it appears the shading we're all experiencing has a name - mura

It's commonly seen as clouding and is caused by many factors, most of which have been overcome with better manufacturing and quality control, but there's also the distortion of the light guide/diffusion layer.

Here is the full list of causes:

Mura Causes in LCD displays:

1 - non uniform tft thickness
2 - non uniform density of Liquid crystal material
3 - non uniform gap between substrates
4 - non uniform color of color filters
5 - non uniform lamp array
6 - non uniform optical filter
7 - warped light guide/diffuser

It's the last one we should be interested in and it is caused by heat in the main.  Interestingly, the one common factor in all the screen issues is the faint line along the right side of the screen and this is where the power (electricity) input is situated.

I've run over my screen tonight, with a non-contact laser thermometer and there's a wide range across the screen.  On the left of the screen, the temps are lower and obviously, the temps rise as you go up the screen.  Mine ranges from 28 celcius at bottom left to 42 celcius at top right.

Now that we're all aware of the possible over-heating issues associated with this screen, I believe that even if the component that is liable to over-heat is still considered to be within safe limits, it is still too hot for the diffusion layer in the backlight system, leading to localised warping.  The most severe shadowing also happens to be nearest to the hottest component within the tv chassis.

I'll continue my research and see if I can't come up with somthing absolutely definitive.  As it is though, I believe we've all got a convincing case for replacement, due to design problems.

[virginreco]

Looks like you're really on the case skipton01.

[virginreco]

I searched 'mura lcd' on Google images and most of the images that appear seem to be more of a clouding effect rather than the vertical shadows that we are experiencing. I'm no expert (carpenter) in this field at all but I do think that if we are going to quote technical issues to Sony we should be 100% sure of where the design fault is and what is causing the problem.

I'm not suggesting you're wrong skippy, I bow down to your expertise. I don't understand the first thing about this electrickety!

A lot of the images lead you to your kind of light reading skippy.

[skipton01]

More digging - seen this teardown of a Bravia set and the label is very informative:

http://www.fullhd.gr/2008-03-14-21-37-34/teardown/7547-sony-bravia-kdl-46ex720-teardown.html

DBEF stands for dual-brightness enhancement film and it basically sits in the panel to reflect light that's polarised one way, but pass light polarised another.

I believe that it's this film that we can see when the screens fail and that the failure is due to the film touching another layer in the panel.

Still researching!

[skipton01]

More digging - seen this teardown of a Bravia set and the label is very informative:

http://www.fullhd.gr/2008-03-14-21-37-34/teardown/7547-sony-bravia-kdl-46ex720-teardown.html

DBEF stands for dual-brightness enhancement film and it basically sits in the panel to reflect light that's polarised one way, but pass light polarised another.

I believe that it's this film that we can see when the screens fail and that the failure is due to the film touching another layer in the panel.

Still researching!

I think this pdf document from a commercial repairer of LCD panels seals the cause:

http://www.febalcdrepair.com/UserFiles/file/febalcdrepair.pdf

The relevant part is the last paragraph of the first section "Polarizer Film Replacement"

[colinmabey]

I have a Sony KDL46V3000  which has developed exactly the same problems as you describe. It is only 2.5 years old and cost me over £1100 so is a bit dissapointing to say the least. From what I read on the blog here it seems little point in raising the iossue with Sony customer services. I will send them a letter with all the details and let you know how I get on.

From a technical point of view does anyone know why these dark shadows are happening. is it a reduction in the output of the LCD panel in this area? Is there possibly any form of reset, or perhaps forcing teh screen to output maximum light levels for a period of time that might reset theses dark areas?

[virginreco]

Hello colinmabey

Read skipton01's posts, he has a background in this sort of thing.

[skipton01]

The dark lines are caused by defects in the polarising layer in front of the backlight.  Whether it's heat or manufacturing issues, or both, the result is the same.  Setting the screen to max brightness will have no effect - once the lines and stains become visible, they will only get worse.