Dell Ultrasharp 2408wfp Shadows

[hgg]

Hi to all,

My name is George, and I am a new member to the forum.
I have the Dell 2408wfp LCD monitor many years now and it has developed a
strange problem. Its more than a year and it has not gotten any worse.

Some dark shadows have appeared on the right side of the panel.
When you press on the LCD screen at the location of the shadows,
they do not change. The problem is more visible at low brightness
levels 20% (which I work most of the time) and less pronounced at
higher levels like 60% There is no similar pattern at the background
picture I am using. I have used the LCD conditioning function from the
menu, but it does not make any difference.

Please have a look at the image below :




I would like to hear your opinion on what could be the most likely cause
of the problem and if it is reversible. Any help is appreciated.

Thank you!
George.

[Agent24]

Re: Dell Ultrasharp 2408wfp Shadows

You can get dark patches on LCDs if they have had physical damage.
Did the dark patch appear gradually or all at once?

If it's not the LCD itself, there maybe something inside the panel assembly, behind the LCD glass.

At a guess, it could be carbon residue from a failing\arcing CCFL lead. But that should cause inverter shutdown...

Can you post a more close-up image of the area? Preferably a macro shot as close as you can get, maybe taken from an angle rather than perpendicular to the screen.

[hgg]

Re: Dell Ultrasharp 2408wfp Shadows

Hi,

The dark patches appeared gradually in a period of a month or so.
This is the closest I can get:




It looks like its something immediately below the lcd screen but not
anything like a carbon residue.

George.

[Agent24]

Re: Dell Ultrasharp 2408wfp Shadows

Mould? Did it ever get damp\wet?

[hgg]

Re: Dell Ultrasharp 2408wfp Shadows

Its not mould.

Today I got my heat gun and heated the affected area at 100 degrees C
and after a while the shadows disappeared! Half an hour later they were back
again exactly as before...

It looks like there is a sort of permanent damage inside the LCD layering.

[HAHOMETP]

Re: Dell Ultrasharp 2408wfp Shadows

I suspect moisture is trapped between the backlight diffuser sheets. Those sheets look like mica, are polarised and stacked in a cross-hatch pattern. I'd take this whole sandwich apart on a large clean table and look before chalking off the LCD. Be sure to note the sequence and the orientation of those sheets as you peel them off. They will need to come back in exactly the same order and orientation.

I have the same problem, albeit far less pronounced, in my larger Dell 3007wfp but don't have the time to address it at the moment.

[hgg]

Re: Dell Ultrasharp 2408wfp Shadows

Risky business... but when I find the time I will try it.
It looks like that the wfp series develops the same problem after prolonged use.
Thanks.

[HAHOMETP]

Re: Dell Ultrasharp 2408wfp Shadows

My problem is entirely man made. I took the backlight diffuser sandwich apart for cleaning with alcohol but put it back together too hastily w/o waiting for the alcohol to dry completely between the layers. Need to revisit it one day.

[hgg]

Re: Dell Ultrasharp 2408wfp Shadows

I see. I thought that is appeared by itself.
There are other owners though that have similar problems with the 2408wfp.
Did you clean them with ordinary rubbing alcohol?

[HAHOMETP]

Re: Dell Ultrasharp 2408wfp Shadows

Yes, it was regular rubbing alcohol. I wish I had some Methanol at that time. It leaves no residue but is very toxic and as such is not sold freely in the US.

Washing those large diffuser sheets is challenging because they have miniscule ribs running diagonally that like to trap moisture. They resemble Fresnel lenses only the grooves are not circular but straight.

[hgg]

Re: Dell Ultrasharp 2408wfp Shadows

Thanks! I might try it.

[Agent24]

Re: Dell Ultrasharp 2408wfp Shadows

There are other owners though that have similar problems with the 2408wfp.

Could indicate a manufacturing problem. Or that the design is susceptible to this problem.