X31 puzzle: LCD issues

[buzz101]

Here's a puzzle for you Thinkpad experts.

My X31 has video issues: everything that is supposed to be black is green, and there's lots of purple streaks across the LCD.

I plugged in an external monitor, and everything looked fine. So the VGA-out signal is good.

I replaced the LCD assembly (which includes LCD and inverter).

The problem persisted!

I take it that the graphics card is fine (otherwise the VGA-out signal wouldn't be fine), and I take it that the LCD and inverter are fine too (because replacing them didn't help anything).

So what's not ruled out as a possible cause for this issue? Thanks for any pointers!

- Buzz101

[andyP]

Welcome to the forum,

you haven't mentioned the LCD cable, and have you checked the cable connection to the mainboard?

[buzz101]

The LCD cable was part of the LCD assembly that I replaced. So the cable itself is most likely fine.

But the connector on the board... I'll have to take a look at that indeed.

Thanks for the tip.

[snv]

I take it that the graphics card is fine (otherwise the VGA-out signal wouldn't be fine)...

I am not sure about that. My impression was that different pins on the GPU are assigned to the VGA (external) and LVDS (internal) interfaces. Can someone who knows for sure either confirm or disprove my assumption? I also have an intermittent problem with my X31, where the screen is only corrupted for the internal LCD.

[buzz101]

I also have an intermittent problem with my X31, where the screen is only corrupted for the internal LCD.

That's how it started with me. At first, I'd have a corrupted screen, but it would disappear when I closed the laptop for a few minutes. Now it is permanent.

This is my second X31 in about 4 years that has given out--they don't have the strongest system boards, it turns out.

[ajkula66]

buzz101 wrote:

I take it that the graphics card is fine (otherwise the VGA-out signal wouldn't be fine), and I take it that the LCD and inverter are fine too (because replacing them didn't help anything).

Your assumption is incorrect. LCD output from the system board is digital whereas VGA is analog, and one can work without the other, I've personally seen it dozens of times.

I'd bet that your GPU has gone south, I'm sorry to say.

Good luck.

[buzz101]

Thanks for the tips, folks.

X31 parts are now for sale in the Marketplace thread!