Dark Patches on Corners of T42P 15" IPS Screen -

[RogerBlake]

Another quick question - my new T42P off Ebay seems to have darkish blotches in the two lower corners extending about 1.5" high from the bottom and 0.75" in width. Is this anything to worry about such as a
sign of backlight problems or something ?

And does anyone know of a site showing pictures of LCD problems with causes ? I would have thought there'd be something like this somewhere on the net but haven't found much yet.

[Harryc]

That is so common on IPS LCDs that I'd almost call it a feature. Not to worry, it is not harmful and it really does not take much (if anything) away from display quality. Enjoy your IPS flexview LCD.

[RogerBlake]

thanks for that Harry - I will enjoy definitely my IPS - if you seen other posts from me you'll know I bought a top-end W700 to replace an older T42P that got broken, and I was not impressed at all with that screen. So hopefully when a couple of other hassles are sorted I'll soon have the best of both worlds - nice 1600x1200 IPS screen on the T42P and quad cores, etc on the W700 (though it would be even nicer to have them on one machine sometime Lenovo ! )

[lophiomys]

slightly off topic:
You made me think.
How about getting new mobo and components in an IPS equipped T42p 15" shell?
The big question would be, if we could attache the old 15" IPS display cable to a modern system?

[Johan]

@ RogerBlake:

As Harry says, the darkening corners of FlexView/IPS LCD's (the older LCD's, the darker, or rather: The more hours the LCD has been "on", the darker) is a fundamental behaviour of FlexView LCD's - try search this forum for e.g. "dark corners" and many hits will show up. The cure? A new backlight (CCFL) for your LCD, which e.g. forum-member jamiphar can help you with (if IBM won't cover this under the warranty, or if the warranty has expired); see the thread LCD CCFL Backlight Repair/GPU Rework - I'll fix it for you!. New UXGA T42p FlexView/IPS LCD's these days can be picked up on eBay for around $100 if you watch out - but in such case you will need to swap out the new LCD with the old... which is a small operation not everybody may want to carry out. There are a couple of images of a T42p in the thread FS: T42 IPS SXGA+/1.8GHz/1GB/80GB/CDRW/ABG/BT - $300 *PIC* where you in one image may see the darkening corners. You may probably find more images yourself by searching or seeing misc. pictures in the Pictures of your ThinkPad & desk setup sub-forum.

slightly off topic: You made me think. How about getting new mobo and components in an IPS equipped T42p 15" shell? The big question would be, if we could attach the old 15" IPS display cable to a modern system?

Something very close is indeed possible, although you will need a T60 shell (and not a T42/p) - as e.g. discussed in the thread Parts for the ultimate 15” T60 UXGA FlexView w/T61(p) mobo? although you need to be aware of the T60 LCD-issue with the correct EDID... (search the forum for "EDID" to learn more about this). Recently there was such a T61p for sale at the Marketplace - it might still be there? See the above-mentioned thread for a link.

Johan

[RogerBlake]

As Harry says, the darkening corners of FlexView/IPS LCD's (the older LCD's, the darker, or rather: The more hours the LCD has been "on", the darker) is a fundamental behaviour of FlexView LCD's - try search this forum for e.g. "dark corners" and many hits will show up. The cure? A new backlight (CCFL) for your LCD,

but how long will a backlight last once it has reached this stage of darkening corners. There's a difference between a slight inherent fault that will not get worse over time, and a fault which worsens over time due to failing components. This machine I've bought is supposed to be lightly used - my old T42P had a perfect screen after 4 years so I suspect this one has been somehat more than "lightly" used.

Replacing a screen/backlight is NOT an option here in the UK as I have already found with the old machine.

[ajkula66]

Well, the good news is that these LCDs are still available in the NOS form...and I'm sure that James would replace the backlight for you, although it may prove to be cost-prohibitive given your location...

IPS LCDs have a shorter lifespan than regular TN panels in my not-so-modest experience. Given that even the youngest T42p imaginable is close to 4 years old now, if it's still running on the original LCD I'd give it 12-18 months of daily use before it starts getting a pinkish hue...

My experiences only.

[RealBlackStuff]

CCFLs or backlights can easily go 6-8 years without showing much deterioration, if any.
Replacing one should extend the life of your LCD by at least another 5 years!

[RogerBlake]

Can I take it from the previous posts that after about 12000hrs (4x8x365+rounding) of use the IPS backlight typically shows the dark corners and after another 4500 (1.5x8x365+rounding) hrs it will show the pinkish tinging, or can anyone provide better "average" figures ?

[ajkula66]

I wouldn't be worried about "average" figures...but would buy a NOS LCD while they're still available...and once your screen dies or becomes darker than you'd like, just swap them...

Both FlexViews in my signature (A3? FrankenPad and T43, from 2003 and 2005 respectively) are on their third LCD...meanwhile there are A31/p units around still running with original LCDs and no issues...

[sjthinkpader]

Can I take it from the previous posts that after about 12000hrs (4x8x365+rounding) of use the IPS backlight typically shows the dark corners and after another 4500 (1.5x8x365+rounding) hrs it will show the pinkish tinging, or can anyone provide better "average" figures ?

I think they have about 5000 hours life. So it is important to set the LCD timer to 5 minutes or so on battery or A/C in the Power Manager.

Dark corner is due to the refraction of light at the two edges, nothing to do with CCF life.

[rkawakami]

Can't some of that blackening be explained by dark spots at the ends of the CCFL? Which is common with older tubes?

[ajkula66]

rkawakami wrote:

Can't some of that blackening be explained by dark spots at the ends of the CCFL? Which is common with older tubes?

That has always been my understanding of this phenomena...

[sjthinkpader]

Can't some of that blackening be explained by dark spots at the ends of the CCFL? Which is common with older tubes?

Could be, but it should be within the rubber boots. The edge has reflective foil covering but it is still a discontinuity of light at the corners.