weird grafic card problem on two Acer 5520G

Hi there,

I got a really weird thing here.

I got two Acer 5520G, both had that failing motherboard problem, both video cards (8600-M GS were okay). So I "repaired" the first one with hot air reflow. It worked again.

I tried the video card of the second one in the now repaired one - works as well.

Now, I had some CPUs laying around, all from either 5520Gs or 7520Gs.

I tried one, worked without problems, tried another one - - no video output anymore - no back light, nothing!?!?!

Damned my luck I think, one card just went dead. So I go back to the other 8600M GS - it works again.

I shut it down, try to reboot - - no video output anymore - no back light, nothing!?!?!

What the heck !?!?!

I try both video cards in an 5920G - again no video output.

I hook up the 5920G to an external display via VGA-out - voilà, I get something on the external screen, internal still black as the night. Same is true for the other card. Both work only with an external display, in three different laptops.

They worked flawlessly before with the internal display.

I tried the keyboard combination to switch displays - no luck. Tried the same via Windows display settings - no luck. I never get anything on the internal display, no backlight no nothing - darkness from POST to Windows to shutdown.

So now my question - what ever could have caused that fault? Any chance to get that straight again? Maybe reflash vBIOS? I have no idea, really ...

Thanks a lot in advance!

 

Your 5520G appears to have a short on the LVDS lanes of the MXM slot, that is severe enough to actually burn out the LVDS circuits on the MXM cards.

 

Thanks - one of them now works again. Did noting to it, but booted it maybe 24 hours later.

The other one still just works with external display.

But nevermind, I will disassemble and sell them as broken.

Cheers

CLOSED

 

Probably the short causes some LVDS bumps to break down. Once the card cools down (or if you reflow it), LVDS comes back until the mobo knocks it out again.