X200 LCD Replacement

[rob_nb]

I have an unusual question / seeking advice

I have x200s - (12.1 WXGA ) Thinkpad

a few weeks ago I cracked the LCD -- yet it was still functional. I ordered a new LCD (i was no brave enough to 'upgrade') I went with a straight replacement( PN 42T0479/FRU42T0480).

I dis-assembled the LCD front bezel as per the hardware manual, replace the LCD, however now when I boot up my laptop the screen is VERY dim -- beyond usable dim. I should point out that before I replaced the LCD, the computer was usable, the LCD was fine - save for the crack- in the LCD.

So I thought. maybe I got a 'bad' LCD form the manufacturer. I put my cracked LCD back in... still cracked . It is very DIM as well. So I think something is going on...

Off to the Google machine I see a lot of posts about LCD inverters, and backlight bulbs. I am inclined to dismiss the backlight as the culprit as the issue is appearing on 2 separate LCD panels. The LCD Inverter - I have no idea where it is (I believe it is part of the LCD array , see #1, under the LCD bezel on pg 149 of hardware manual). Though I do not know as that does not appear to be a piece that can be replaced, as it is part of the larger LCD ribbon/cable that is plugged into the motherboard. Besides, it would be a heck of a coincidence if the LCD inverter were go the day I decided the swap out my LCD.

thoughts ?

TL;DR: replaced a crack LCD on x200 - no LCD is very DIM, beyond usable.

[erik]

welcome to the forum!

most of the time this phenomenon is caused by LCD cable damage.   despite replacing hundreds of thinkpad displays myself, it's happened to me once or twice.

my best recommendation would be to get a new cable and see if that helps.

btw, your X200s' panel is LED and doesn't have an inverter.   instead you have an "LED board" that drives the status LEDs you see on the display bezel and top lid.

[rob_nb]

Thanks for the response erik.

Just so that I am clear -- I have an LCD panel, which is LED backit ? Correct ?

And we're thinking I need to replace the LCD cable assembly, with Bluetooth connector (FRU 44C9919) - as I currently have Bluetooth daughter card, so no need to replace that (#7 pg 281 of Hardware Manual)

You think maybe I damaged the cable installing and uninstalling the new screen ? I really have no idea how to be any gentler. I mean I was careful, but hey, stranger things have happened.

So to replace the ribbon, I need to crack open the bottom half (keyboard side) of the laptop correct ?

[erik]

yeah... TFT panel, LED backlight...

44C9919 is what you would want.   this won't guarantee a fix but i honestly don't know what else could have gone wrong (despite great care) along the way.

yes, to get the cable completely out you'll need to remove the keyboard and keyboard bezel.

you'll be able to test the new cable while everything is apart.   just be careful with the parts and you should be fine.

if it helps, here are the official service training videos for the X200: http://www.lenovoservicetraining.com/io ... index.html

[rob_nb]

so.... I have an update.

swapped out the 44C9919 - LCD ribbon, same situation. LCD is still VERY DIM. (I tried both LCD, cracked and new - and both ribbons. same same.

So now I am thinking - is there a sensor, or a switch that somehow turns of the back-light, when the lid is closed.... that somehow the laptop is 'confused'. I know I am reaching here.

thoughts ?

[khtse]

so.... I have an update.

swapped out the 44C9919 - LCD ribbon, same situation. LCD is still VERY DIM. (I tried both LCD, cracked and new - and both ribbons. same same.

So now I am thinking - is there a sensor, or a switch that somehow turns of the back-light, when the lid is closed.... that somehow the laptop is 'confused'. I know I am reaching here.

thoughts ?

The X200 doesn't have an ambient light sensor. The switch that turns off the monitor when the lid is closed is just an on-off switch, so the monitor is either on, or off. Of course you can adjust the brightness of the screen with appropriate softwares, but there is no hardware sensor.