T42 LCD

[tholmes24]

Hey just wondering if anyone else has a wierd shadow on the bottom right of there lcd... Thanks Tom

[richk]

shadows in the lower corners is caused by dark areas at the ends of the backlight bulb. It means the bulb is nearing the end of its life.

[tholmes24]

Where is the backlight bulb on a T42?

[richk]

Inside the sealed LCD panel, along the bottom. It is difficult to replace. I would suggest learning to live with the problem until it gets worse. It may work as it is for a long time.

[kyrotech]

Yes the backlight of the LCD is a non serviceable part of the LCD Panel . If you want to fix the problem you need to replace the whole LCD Panel .

[Johan]

Yes the backlight of the LCD is a non serviceable part of the LCD Panel . If you want to fix the problem you need to replace the whole LCD Panel .

I am not certain that the above statement should be so definitive with respect to the possibility of fixing a worn-out backlight... since forum.thinkpads.com user jamiphar actually offers to replace ThinkPad backlights - see the thread LCD CCFL Backlight Repair/Replacement - I'll fix it for you!

Maybe worth considering, rather than replacing the entire LCD assembly?

Best regards,

Johan

[dr_st]

Um, how big are the shadows and how dark? What screen size/resolution is it?

Most 15" Flexview screens on T42 have small (half a centimeter) areas in both bottom corners that are slightly darker. It's normal and by no means indicates the approaching death of the backlight.

[Johan]

Um, how big are the shadows and how dark? What screen size/resolution is it?

Most 15" Flexview screens on T42 have small (half a centimeter) areas in both bottom corners that are slightly darker. It's normal and by no means indicates the approaching death of the backlight.

Wow, this is very interesting information! I have recently noticed that the approx. 3-year old 15" Flexview/IPS SXGA+ T42 in my sig has such slightly darker areas in the lower left/right corners... but I am uncertain of whether they have been there always, and that it is just me who have first become aware of them recently - or if they have actually first developed recently? [NB: I tend to believe that they have not always been there...]. Assuming that you are correct (stating that this is normal), then how do you distinguish such normal black area versus something which indicates a failing backlight??

Yet a reason for asking: According to the thread 15" UXGA Problem, Like pressing mark these slightly more black areas are indications of a failing backlight... leading to these questions:

1) What to believe, when?

2) When to invoke the warranty?? (while still possible!)

Does anyone have experience with IBM confirming and accepting that such slightly black areas are indeed signs of a-soon-malfunction display, and replacing the backlight (or entire display) under warranty while it is still "mainly" functioning OK? How bad shall it be before IBM will replace it??

Thanks in advance for sharing experience on this!

PS: An easy way to see if a display has such dark spots is to use the white screen in the (freeware) program: Dead Pixel Buddy.

Best regards,

Johan

[Troels]

It tends to get worse with age. It works just as a normal CCFL seen in light armatures - they are darker at the ends, and don't offer a completely uniform lighting until after a few minutes of warm-up.

The dark areas at the left and right side of the display depends on a lot on luck, since not all CCFLs has the same exact alignment or finish of the CCFL.
I have seen three flexview displays, 2 UXGA, 1 SXGA+. The SXGA+ has a darker right side, but great left side. One of the UXGAs is dark in both ends, while the newest UXGA only has a slightly darker 3x3 mm patch in the lowest right area.

On the backside of the screen, it says what backlight has been used - the UXGA with two dark sides has the following information regarding the CCFL:

BL P/N: 000F350
BL EC: 000F05A
BL LOT NO: G06-PC-3
CFL LOT NO: SLa -P

I do not recall the details for the SXGA+, but the CFL lot no. was indeed different.
The CCFL has a MTBF of 10,000 hours, so i personally wouldn't worry about it dying before the inverter for example. A dying CCFL will be very yellow and will have a low brightness, so when you feel that the brightness is much lower than it used to be, it's probably time to replace it.