T23: Backlight dead?

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stgreek · #1 Post by **stgreek** » Mon Feb 20, 2006 10:57 am

Hello everyone. My girlfriend's trusty old T23 started exhibiting weird symptoms around 2 weeks ago: The screen would start flickering with a reddish colour, and a hissing electrical noise could be heard from within the screen. This would happen randomly, and could last from 2-3 secs to an hour.

But last night, it bit the dust. A strange noise was heard and then the screen turned dark. Note, dark, not off. I can still very feintly see the desktop, but it is too dark to see the mouse cursor for example. Therefore, I am thinking that the backlight is dead.

Is this the case or could it be something else? And if it is, do you think it is worth repairing or does the screen need replacement? (this is an SXGA+, so I am better off buying a new T4x than repairing it for 500 Euros). Obviously, the laptop is no longer under warranty, or it would be on its way to a repair depot when it first exhibited the issues.

Orevin · #2 Post by **Orevin** » Mon Feb 20, 2006 11:19 am

It's weather the backlight or the inverter board. Use the forum search, there are a lot of hints.

A repair should not cost 500 EUR. A new back light is about $20 shipped, a inverter board maybe 50. The board is easy to replace (see HMM), while the backlight is a little more tricky (http://forum.thinkpads.com/viewtopic.php?t=3705), but doable.

Website · #3 Post by **tfflivemb2** » Mon Feb 20, 2006 11:27 am

The red tint is a clear indication of the backlight. The only time that it is between the inverter and the backlight is if all of a sudden there is no lighting on the LCD.

Since you were able to see problems with the discoloring, you can pretty much eliminate the problem being the inverter. As another member previously said...either the inverter works or it doesn't.

chan_man · #4 Post by **chan_man** » Mon Feb 20, 2006 11:59 am

Both the inverter and the backlight are not hard to repair. The inverter card is located directly under the screen where the hinges are. You need to remove the 3 plastic covers to get to the screws (3 on the bottom), then you have to "pry" open the inner cover. It is easier to do this with the screen opend up all the way so that it is flat, you can see the seam better. There are two cables to unplug and it is out. The backlight is a bit more involved, there are 10 additional plastic covers (5 on each side) and the screen should come out. You then need to get the metal band around the screen to come off. Follow the wire from the inverter to the screen, it is attached to the backlight.

#5 Post by **carbon_unit** » Mon Feb 20, 2006 5:25 pm

I have changed the backlight on a few T23's and I have seen that not all LCD's are built the same. Some are easy to get the bulb out and some are nearly impossible without breaking anything. Simply removing the metal band around the LCD is not always simple.
Then you have to source a backlight. I don't know where you are going to get one in europe but I am sure they are available somewhere.
Depending on your technical expertise it may be easier to get a whole LCD or a complete display with cover and swap it out.
The Hardware Maintenance Manual will get you as far as replacing the LCD but not the backlight.
Good Luck.

stgreek · #6 Post by **stgreek** » Fri Feb 24, 2006 8:15 am

Thanks for all the replies, I have one last question:

I have decided to swap the LCD, as I dont want to mess with soldering stuff. My question is, is there a different assemply for SXGA+ or will an XGA assembly do the trick? I can easily find the latter, and quite cheap too, but the former is impossible.

stgreek · #7 Post by **stgreek** » Fri Feb 24, 2006 8:17 am

Orevin wrote:It's weather the backlight or the inverter board. Use the forum search, there are a lot of hints.

A repair should not cost 500 EUR. A new back light is about $20 shipped, a inverter board maybe 50. The board is easy to replace (see HMM), while the backlight is a little more tricky (http://forum.thinkpads.com/viewtopic.php?t=3705), but doable.

With regards to your comment, the 500 EUR quote is from IBM, as they swap the whole screen, even for such simple problem as a backlight. Add man-hours and delivery, and we are talking upwards of 600 EUR :S

Website · #8 Post by **tfflivemb2** » Fri Feb 24, 2006 9:21 am

One thing that you might want to try, just to make sure, is connect the laptop to an external monitor to see if you get a clear picture. If you do, then it is the backlight for certain.

I think if you switch from SVGA to XGA, you might need to replace the LCD cable as well. I believe that I read that they have different connectors.

stgreek · #9 Post by **stgreek** » Fri Feb 24, 2006 12:53 pm

tfflivemb2 wrote:One thing that you might want to try, just to make sure, is connect the laptop to an external monitor to see if you get a clear picture. If you do, then it is the backlight for certain.

I think if you switch from SVGA to XGA, you might need to replace the LCD cable as well. I believe that I read that they have different connectors.

The laptop works fine with an external monitor, so I am sure it is the backlight. I do NOT want to switch from SXGA+ to XGA, I am asking if the LCD is what determines the resolution or if an XGA LCD assembly can be used with an SXGA+ cable/whatever.

Zedicus · #10 Post by **Zedicus** » Fri Feb 24, 2006 2:26 pm

normally its just the LCD that determins the highest res. ive never had a chance to mess with a xga t23 though so i cant tell you if there is a difference on that specific model.

T23: Backlight dead?

T23: Backlight dead?

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