DELL Ultrasharp 2408WFP Shadows - Page 1
Forum section: electronics / projects

author: hgg
author_rank: Frequent Contributor
timestamp: November 24, 2013, 01:18:19 pm
content: Hi guys,I have been using this monitor from 2008 and it served well with excellent images but the lastyear it developed some shadows on the right side of the screen that are more pronouncedwhen the monitor is just switched on. When it warms up they fade a bit but they are clearlyvisible.Has anybody had a similar problem? Do you know if is it serviceable?Thank you.(you can see the shadows in the right lower side of the image)Dell LCD Problem

author: PA0PBZ
author_rank: Super Contributor
timestamp: November 24, 2013, 01:55:33 pm
content: If it gets better when warming up it could be the CCFL lamps reaching end of life. The picture is not very helpful for me though.

author: SeanB
author_rank: Super Contributor
timestamp: November 24, 2013, 02:00:02 pm
content: Time for new CCFL tubes there. They are blackening and this will eventually get to the point where the inverter will shut down.While you have it apart you might want to look at the PSU capacitors and change the worst ones.

author: nctnico
author_rank: Super Contributor
timestamp: November 24, 2013, 02:04:52 pm
content: IIRC I still have a TFT panel for this monitor. The PSU developed bad solder joints which caused the output voltage to rise way too high. It wrecked the 5V parts on the controller board.

author: hgg
author_rank: Frequent Contributor
timestamp: November 25, 2013, 06:58:14 am
content: Hi,Sorry for the late reply. We had yesterday very heavy rain, blackouts and no internet....Thank you for your replies. Please have a look at a slightly better picture that shows the problembetter.Dell ShadowsThese shadows do not change place. If it was the CCFL wouldn't it be more black at the far rightend of the screen? The middle right is still white.Thanks.

author: marshallh
author_rank: Unknown
timestamp: November 25, 2013, 10:15:07 am
content: Probably condensation residue (precipitate?) on the inside. Could be inside the LCD panel (between glass and plastic light diffuser sheets) or on the outside of glass, or inside the display antiglare layer if there is one. Take it apart and clean it?Also, I see somebody's extracting a certain popular CAD package

author: hgg
author_rank: Frequent Contributor
timestamp: November 25, 2013, 10:44:10 am
content: Himarshallh,That's what I thought as well in the start, but I wasn't sure. The monitor gets warm, and itworks 24/7, so any humidity would have been gone, or at least the pattern of the shadowswould have changed, don't you agree? When I press on the shadows they don't change.I also read that it contains 7 CCFL bulbs??? It does not look like a CCFL problem though.http://www.manualslib.com/manual/227789/Dell-Ultrasharp-2408wfp.html?page=5#manualHard to find a service manual fro this one.I was sure that I will get a comment about the unzipping...Only a few characters gave it away... Try before you buy.

author: Psi
author_rank: Super Contributor
timestamp: November 25, 2013, 10:50:26 am
content: Quote from: hgg on November 25, 2013, 10:44:10 amWhat does your desktop background look like? Does it by any chance have a pattern which matches the pattern on the LCD in that corner?My 8 year old Dell 24" (similar model) is showing a pattern top-left which i know is burn-in because you can see some desktop icon shaped blocks in it.

author: hgg
author_rank: Frequent Contributor
timestamp: November 25, 2013, 11:06:15 am
content: Hello Psi,Its not a pixel burnout either. The desktop background is different and on top of the shadows areusually windows with even white or colour background.

author: Psi
author_rank: Super Contributor
timestamp: November 25, 2013, 11:31:27 am
content: What about during the parts of the 24h period every day when its not being used?

author: hgg
author_rank: Frequent Contributor
timestamp: November 25, 2013, 12:11:43 pm
content: Psi, the shadow patterns do not match any of the images that I display on the screeen,background or otherwise. If it was a background imprint on the LCD it would have happenedelsewhere on the screen as well, especially on the left side were there are parts with thesame background 24/7. Its only on the right side though, were the screen is changingall the time.It looks like a defect on the panel inside layers but I am not really sure.

author: amyk
author_rank: Super Contributor
timestamp: November 25, 2013, 12:17:27 pm
content: That looks more like dirt/dust than anything else.First thing to try (hopefully you've done it already) would be to wipe the surface... then you may carefully disassemble the panel and clean it.

author: hgg
author_rank: Frequent Contributor
timestamp: November 25, 2013, 12:29:35 pm
content: The panel is clean on the outside...It is no dust or dirt either.The shadows appeared abruptly after a 3 month period that the monitor was not used at all.

author: marinedalek
author_rank: Contributor
timestamp: December 04, 2013, 06:49:30 pm
content: Where was it stored for that 3-month period? Anywhere that it could have been submitted to humidity/damp? It's tricky to tell from the images but it could be fungus, often also found in camera lenses. You can get anything from spots and streaks to a spidery haze (which you seem to have). The only way to fix that would be to disassemble and clean the display thoroughly. As you move your head from side-to-side, is the patterning in front of or "behind" the image on the screen? If the latter then the fungus could be in the diffuser rather than the TFT panel itself.

author: envisionelec
author_rank: Frequent Contributor
timestamp: December 07, 2013, 03:17:15 am
content: The LCD stack is delaminating. There's nothing you can do short of replacing the panel. I had the same problem on a panel of similar vintage.

author: hgg
author_rank: Frequent Contributor
timestamp: December 07, 2013, 07:09:27 pm
content: QuoteIts bad news then...nctnicoare you selling your panel ?...

author: nctnico
author_rank: Super Contributor
timestamp: December 07, 2013, 09:16:20 pm
content: I looked it up. The panel I have is an LM181E06 (A4M1). BUT it seems I have harvested some of the backlight connectors from it and the surface has some scratches. All in all you would have to take the panel apart to exchange the LCD screen itself. You can have it if you pay for the postage but expect that to be in the ballpark of €27,- (plus some Paypal fees).Maybe you are better off looking for a second hand TFT display with a defect. Usually its something simple like a blown fuse or bad capacitors.

author: hgg
author_rank: Frequent Contributor
timestamp: December 08, 2013, 07:40:02 am
content: Hi, but the LM181E06 panel is 18.1" and mine is 24"...

author: nctnico
author_rank: Super Contributor
timestamp: December 09, 2013, 06:25:19 pm
content: I already typed 'IIRC I have a panel'. I'm sorry to be wrong

author: hgg
author_rank: Frequent Contributor
timestamp: December 09, 2013, 07:02:56 pm
content: That's ok, I was happy for a second.

author: hgg
author_rank: Frequent Contributor
timestamp: October 26, 2014, 11:47:12 am
content: An update...Dell 2408wfpI am still using the same monitor and the problem remains exactly the same.Yesterday I tried heating up the affected region that has the dark shadowswith the heat gun and after a while the shadows were gone and the screenhad a uniform brightness again. That did not last though. Half an hour laterthe shadows returned exactly as before!So, it looks like that the damage has to do with the inside layering of the LCD .Any other possible explanations?Thanks.George.

author: wraper
author_rank: Unknown
timestamp: October 26, 2014, 12:39:15 pm
content: This is a backlight issue, polymer films dissipating light are damaged. Likely moisture got in and considering where you live, there could even be fungus grown inside. There is nothing you can do except replacing lcd panel or at least backlight unit which is not practical and moreover easy at all.

author: hgg
author_rank: Frequent Contributor
timestamp: October 26, 2014, 12:50:53 pm
content: That's what it looks like.I don't think that there is any fungus though because the monitor is always on and when offthe relative humidity is between 40-50%. Also, when I heated the screen, the shadows disappeared.Maybe one of the layers shrunk for some reason and it does not lay completely flat with the other layers.It turns out that there are some times that you wish for bad caps...Anyway, time for a new screen.Thanks.

author: wraper
author_rank: Unknown
timestamp: October 26, 2014, 02:01:46 pm
content: You wrote earlier that it was off for a three months. If fungus are grown, they won't disapperear. When you are heating, maybe fungus dries temporarily. Actually I don't know how much it is an issue with monitors. But fungus is very serious issue with DSLR optics.

author: hgg
author_rank: Frequent Contributor
timestamp: October 26, 2014, 02:04:55 pm
content: My DSLR is in the same area and its fungus free.

author: nukie
author_rank: Frequent Contributor
timestamp: October 26, 2014, 10:08:47 pm
content: My 2408 has been doing this for quite sometime already, same rightside shadow. it went through quite a lot of hours, I don't plan to do anything to it unless it gets worse.Not just DSLR optics but generally all camera lens, fungus attack the multicoating. Give it some UV once a while.

author: tom66
author_rank: Super Contributor
timestamp: October 26, 2014, 10:31:11 pm
content: I've seen this with quite a few LCDs, it is called Mura, named after the Japanese word for "unevenness" (I believe)There are two types.Type A - This is caused by the LCD panel de-laminating and typically looks like a large blob-ish region of darker pixels, a smudge of sorts.Type B - This is caused by the backlight diffuser layers becoming contaminated with moisture or dirt. The effect is often random and looks almost as if the panel is dirty but cannot be cleaned.Personally it looks like type B... this may be fixable but it is involved as you will have to take the panel apart. And there is a risk you will break it in the process.

author: hgg
author_rank: Frequent Contributor
timestamp: October 27, 2014, 07:59:48 am
content: @nukieThat explains it... It might be a common problem with these.Were did you buy yours? I bought mine from Germany, ebay.@Tom66Thank you for the info. As you describe it it does look like type b, but I find it difficult tosee how it got contaminated. It is been used in a clean and dry environment.I've seen the layering in other LCDs and there is a lot of space for disaster if you try todisassemble them. Do you think that it might be just a case of contamination in betweenthe layers? (I am very curious now to open it and see what' s going on)When I heated the affected region with the heat gun on around 100 degrees Celsius,the shadows disappeared. Can this happen if the mura is of type A?(Mura in Greek are called all types of berries like blueberries etc...)Thanks.

author: nukie
author_rank: Frequent Contributor
timestamp: October 28, 2014, 02:44:16 am
content: I bought it direct from Dell. If I apply pressure around the area I can see it heal.

author: hgg
author_rank: Frequent Contributor
timestamp: October 28, 2014, 06:06:50 am
content: Maybe its a different problem because if I apply pressure it becomes even darker.It only gets better if I heat it.

author: Shock
author_rank: Super Contributor
timestamp: October 28, 2014, 10:30:24 am
content: Turn off the monitor, then clean your screen so this next part doesn't leave scratches.Use a microfiber cloth (with another cloth loaded inside it if you need to) to form an even pad a couple of inches wide. Applying an even (but not screen breaking) pressure, rub from the center of the screen evenly to the outside of the edge which has the problem. Do this several times then check if it improves.If this fails then detach the LCD screen from the diffuser and clean both inside sides with an antistatic cloth, and alcohol if required. It's also possible to replace the polarization film on the inside of the LCD but if bonded you need to use several pieces of tape and some dowel to slowly roll it off evenly. Then prep and apply a replacement.Of course do all this at your own risk.

author: hgg
author_rank: Frequent Contributor
timestamp: October 28, 2014, 10:54:50 am
content: Hi,I've just tried your suggestion. No results. When you press it it gets darker but when you releaseit returns exactly as before. (I tried with the monitor off as well) The only thing that worked wasthe hot air which fixed the problem for half an hour.I am curious now to see what the actual problem is. I think I will have to open the panel...

author: Shock
author_rank: Super Contributor
timestamp: October 28, 2014, 12:07:09 pm
content: Static build up between the diffuser and the LCD panel is my suspicion, there might be some kind of growth however causing it. I wouldn't expect the lighting to put out that much of a definitive pattern and you can remove the diffuser and hold it up to light if you need to check it anyway. You just need to be ultra careful pulling it apart if you want to ever reassemble it.If it was polarization film coming off I would expect it to look more uniform. But since you mention heat fixes it have you seen this?

author: hgg
author_rank: Frequent Contributor
timestamp: October 28, 2014, 12:13:28 pm
content: That was the video I saw, but when I applied something cold, the shadows got even worse!So I said lets try the heat gun, but I was happy only for 30 minutes.