Image retention - nec 2490 -- is this normal?

Namelessme

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I received my replacement NEC 2490 in today from an eBay reseller. The first one had a bunch of dark spots and a vertical line down the screen.

The new one looks pretty decent so far, although I am still testing things. But I have noticed some image retention going on.

If I look at a bright screen in my browser, for instance, let's say yahoo.com, read it for a min or two, then go to hardforums, I can see the outline of the previous page in the background. It's faint... and it goes away, but why is it there at all? Does this happen with most IPS screens or 2490s?

The hours used on this isn't insane (9400ish), so it's not like it's a super elderly monitor yet. Is this a flaw with the monitor or do most IPS screens have this, to one degree or another?
 

BassDX

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I bought a used 2007FP a few months ago, and also had image persistence issues. The amount of usage was also around 10K hours. Generally though, the risk of image persistence increases when static images are displayed on the monitor for long periods of time, so simply knowing the hours used doesn't necessarily tell the whole story here.

Anyway, it is true that IPS panels are more prone to this issue in the long run, but in general it is a rare occurrence on modern LCD's. Unfortunately like me you were just unlucky, just ask the seller for another return as honestly dealing with something like this is extremely annoying during day to day use.
 

Namelessme

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Thanks for the reply. I don't think the reseller has any more in stock. I could do a return for a refund I suppose, although honestly at this point was simply hoping to get a defect free monitor or figure out a workaround. There is always the chance of getting something worse too. Believe it or not the first 2490 I received had 40,000+ hrs. It still had enough backlight left to run so it was mostly usable (admittedly it was a bit dim), except for screen defects (dark spots, line, etc). I'd hate to replace a 9K monitor with another 40K one.

Another thing I noticed, which I find very bizarre, is a similar vertical line on the screen as my first 2490. It is so similar to the first defective 2490, I began wondering if it's my dvi cord, but I tried two vga cords and it has the same problem.

It's basically a faint vertical line, yet only visible upon certain light colors. Black, bright white or dark colors and it's not easily seen. Yet if I load up photoshop, it's clearly seen on the gray background.

You can see it here on my first 2490: http://imageshack.us/photo/my-images/62/lcddefect2.jpg/

It actually looked worse in person than it did in the photo. The newer 2490 isn't as bad, but it's a very similar sort of dark vertical line.

Anyone have any ideas how that occurs? Perhaps a pressure point? Or a general defect that happens when monitors age? Or is that another form of image retention... one that doesn't ever go away? The reseller was kind enough to examine the replacement monitor for defects before shipping it to me, but it looks like some problems slipped through.
 
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tk-don

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I'm late as usual. Just tested yahoo.com main page for 10 mins, and then going to hardforum.com main page. I don't see anything out of the ordinary, i.e. no hint of image retention. Mine has around 2.6k hours of usage. Is overdrive enabled in the advancd menu?
Really old IPS generations (DD-IPS) and the much more recent FFS technology is more prone to image retentions. DD-IPS also has a slightly higher amount of pixel cross-talk, and on some patterns and web-pages it is easier to see.

The "burnt grey" may be heat related, or that the reflective back plate polarizer has become damaged by something. Maybe excessive UV. I've seen this occur on CCFL-backlit panels only. :(
 

Namelessme

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Thanks for the reply. Overdrive is turned off, monitor reset back to factory conditions. I doubt revisions matter in this case, but this one was made in 12/2008, so it should have a later revision -- according to hours used, it was used for about 2.5-3 years.

I've seen some reports of ACD displays (which use the same panel, if I'm not incorrect) showing some signs of image retention, so thought perhaps it was panel related. I'd probably guess now it's simply how the previous user used the display. Maybe they sort of abused it a little, running flashing images, or something.... or it's just bad luck.

My first defective 2490 had the same issue, but it also had an insane amount of hours on it (40K+) so just assumed it was hours related.

The big burnt-in vertical line, or big 'L' shape is a bit odder. Same area as the first 2490 I had, so whatever was done to it, was done to both monitors. My best guess that it may be simply burn-in, from some image that was left on the screen too long, seeing as both monitors have the problem in basically the same exact place.

I'll assume there is no way to fix or minimize the problem, or problems, I should say? I find the big 'L' more bothersome than the image retention when changing websites.

The reseller has offered a full refund, or a partial refund if I decide to keep it. I am just trying to figure out if I can minimize the problem or live with an 'L' shape on my screen. Thankfully for most multimedia stuff, the 'L' isn't that visible. But with photoshop, and light colored screens, it sure stands out.

Something I posted in a different thread is another alternative... two people local to me are selling a 2170 and 2470 with very low hours on each (<500). I could use one of those as my main, use this somewhat defective 2490 as my secondary/backup. I'm just not sure if it'll seem too big a drop-off going to the 70 series. If you've had either and can say how they compare, I'd appreciate any opinions. The 70s seem to have some ghosting reports, however... which scares me a little bit... And knowing my luck with used monitors so far -- two 2190s, both w/faulty power supplies, two 2490s, both with screen problems -- I half expect the next used monitor I get will burst into flames as soon as I turn it on.
 

tungt88

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IMO getting refurbished NEC monitors directly from NEC is a good option; NEC offers a 1-year warranty on their refurb models, and very competitive pricing, selling used LCD2490WUXI2's for as low as $270 sometimes ... here's a link.
 

Namelessme

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The price for a NEC 2490 refurb is reasonable. Strangely the smaller model 2190 is more expensive, and what I originally wanted to get as an NEC refurb, but it goes for close to $500. I guess it's a matter of supply and demand.

But the problem is that the 2490 is a second generation one. So no A-TW and a heavier AG coating (based on what people have said here).

The AG coating on the 1st gen one I have now is pretty much at my upper limit before my eyes rebel on me. I find the A-TW a pretty cool feature, no white glow. For what I want, light to med AG coating (at most), good blacks of VA, or at the least, no white glow in IPS, my options are limited.
 

tk-don

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Did the seller indicate anything regarding what the monitor was used for? If the first 2490 had a defect in the same location with the same shape, it sounds like someone using it for work, and never turning it off after leaving from work.
If it is indeed just retention and not permanent burn-in, the "laziness" of the pixels can be removed by showing full black and full white images. This would charge and discharge the cystal material, forcing it to take a full block-nonblock cycle. After a day, the retention should be much lower, if not completely removed. So it might be worth a try.

Apple only did 24" LED edge-lit models, didn't they? If yes, then the panel construction is quite different and more recent.

I don't know anything about the 2470, other than it is one of those rare S-PVA panels with a native gamut close to sRGB. Finding a S-PVA based monitor with a sRGB gamut is not that easy. Here's a review, if haven't already seen it: http://www.prad.de/en/monitore/review/2007/review-nec-lcd2470wnx.html#Introduction
 

Namelessme

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All they could say was that this batch came off-lease. It is a non-touchscreen version, so I don't see it being used in a sales kiosk or anything (probably), but they couldn't say how it was used exactly.

I can set up a screensaver with full black, then full white and give it a shot. About how long do you think each screen should be displayed before switching to the other color?

And yep, the ACDs were LEDs, but could have sworn they used the same exact panel. Or perhaps a variation on the panel. Not that it matters really.

And thanks for the prad review. I read it before though. The comments about artifacts when gaming is what scared me a little. That, and some reports here of ghosting just doing normal pc stuff (like scrolling), makes me a little wary. Yet for some users, they say they can't see much ghosting at all. There was one person here who said he couldn't even tell his 2470 and 2490 apart, besides the gamma shift issues. Although I had assumed the 2470 would have deeper blacks.

The price for the 2470 locally is about $140, and has like 280 hrs... so that seems decent to me. But I am also assuming the low usage has to do with the user simply not using it, not because there is a problem with the monitor. Another seller on craigslist near me has a 2170, w/ just under 500 hrs or so, and wants $60. I'd lean toward the $60 one, as it's less of a risk price-wise... although it may be more of a risk safety-wise when picking up, as his emails are a little peculiar.
 

Namelessme

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Just a minor bump and question...

I tried the flashing white/black images, ran it first for about 2 hrs and it didn't make a difference. I tried it another time for about 4 hrs, and it didn't help either. I used a screensaver and set it for the 'fast' interval, which is about 5-6 seconds between white and black screens.

Anything else left to try? Should I run the screensaver longer? I have read that another method is to run a completely white screen -- typically it says to leave it on as long as the original image was displayed, but in this case that would be impossible. And that is assuming that is the cause to begin with. Any danger running a completely white screen for 6-12 hrs as a screensaver? I don't want to somehow mess up my whites or anything like that.

I also picked up the NEC 2170 I mentioned above, which is an okay spare/secondary monitor. I passed on the 2470 when the seller seemed hesitant to let me see it running.

I found it interesting to compare the 2170 to the 2490. Better blacks, somewhat better whites, somewhat less AG coating, feels like slightly less input lag... but definitely worse in everything else. The images overall on the 2170 are definitely less colorful and 'real feeling' compared to the 2490, but that would be expected. The reseller offered me a decent partial refund due to the burn-in on the 2490 (half off), so overall it was relatively cheap and makes it easier to live with its retention problem -- although if I can never fix the 'L' issue, it may make a better secondary monitor than my main.
 
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