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Look: Whats the problem? Lcd? Cable? Inverter? Motherboard?

Posted: Fri Jan 11, 2013 9:42 pm
by Cyberstudio
Hi guys.

I was using my t400 right now, and out of the blue the screen started to look weird. Looks like there is a mesh over it. It looks pixelated.

Please look at the screenshot bellow:

Image
image ru
As you can see, the first part of the screen looks ok, but after that, everything looks pixelated. I have tested it with both video cards (Radeon and intel) and it doesnt matter. It looks like that on windows/linux/bios.

Look what happens if i open a window with black colors on it (Like CMD)
Image

As you can see, bellow the window the colors look much better, but on the sides there is discoloration

The problem doesnt appear on an external screen. The machine works normal anyway.

What do you think is broken here? The screen? the screen cable? the inverter? I tried disconnecting and connecting the screen cable again, but the problem persist.

This is a 1440x900 screen (the LED one)

Edit:

Here, i have a T61 with a good screen but a dead motherboard, 14in widescreen, looks identical to the T400. What do i need to swap the lcd from the T61 to the T400? the T400 display cable is wider on the motherboard connector.

the T400 is led, the T61 is not. Do i only need a T400 display cable for non led dislay?

sorry for my bad english

Re: Look: Whats the problem? Lcd? Cable? Inverter? Motherboard?

Posted: Sat Jan 12, 2013 7:21 pm
by richk
Your T61 panel would work with a different cable, but the bezel and lid are different. Your t61 inverter would be compatible. It could be the panel or the motherboard. It is just a guess to decide, but my guess would be motherboard. Cable is unlikely and LED screens don't have inverters (they run off DC and an inverter converts the DC on the motherboard to the AC needed to run the CCFL backlight.)

Re: Look: Whats the problem? Lcd? Cable? Inverter? Motherboard?

Posted: Sat Jan 12, 2013 8:13 pm
by Cyberstudio
Hi! thanks for your answer.

what makes you think is the motherboard and not the panel itself? An external monitor don't show those problems at all. This machine has switchable graphics. I have tested it with both video cards and the problem persist on the integrated lcd, but it doesn't appear on an external screen.

Re: Look: Whats the problem? Lcd? Cable? Inverter? Motherboard?

Posted: Sat Jan 12, 2013 9:32 pm
by ajkula66
There are two separate outputs from the GPU(s): analog for the VGA and digital for the LCD. One can work fine while the other one shows corruption.

I agree with Rich that the board itself is the most likely culprit.

Re: Look: Whats the problem? Lcd? Cable? Inverter? Motherboard?

Posted: Sat Jan 12, 2013 11:33 pm
by Neil
If you can change the look of the artifacts, or make them go away completely, by squeezing or slightly flexing the LCD panel (lid), then that would suggest the panel driver circuits are at fault.

Re: Look: Whats the problem? Lcd? Cable? Inverter? Motherboard?

Posted: Sun Jan 13, 2013 8:40 am
by Cyberstudio
Ohh god. While i was waiting for answers, i got the entire display assembly on ebay (will arrive on wednesday i think).

Its very unlikely that the panel is at fault here? :?

I have a W500 here too. Im wondering if the display cable is compatible with the T400. That way i can test the t400 display on the w500. Just the display, i know that the display assembly wont fit.

Re: Look: Whats the problem? Lcd? Cable? Inverter? Motherboard?

Posted: Thu Jan 17, 2013 2:49 am
by systemBuilder
I replaced a panel last week that had a problem that looked like your second problem, it was a "matrix failure" mode of the LCD. If the VGA output is good, there is a very high chance that the problem is in your LCD, inverter, or cable. Since you have purchased a new lid on EBay, with LCD, inverter, and cable, you are cleared for takeoff - just replace the panel and see if it works.

I bought a replacement lid on EBay to fix my problem, but the replacement had an intermittent "I turn off" problem. I sent that lid back to the seller. A week ago, I replaced the LCD with matrix failure, using a $30 used screen, and I'm typing on that machine right now. Best wishes!!