Replaced LCD screen blank, external monitor just fine

Hello guys,

the hinges of my girlfriends MacBook Air (Late 2008 - A1304) broke so eventually also the screen died (more the cable I guess). We bought a new screen assembly off ebay and exchanged it but the new LCD screen stays white all the time. You can control the backlight LEDs via the function buttons. Also the camera + AirPort works. But no image.

Now the strange thing is that if we hook up an external monitor (miniDVI) it works just fine - that was also the solution before the new screen was mounted. In the system settings the newly mounted screen even appears as 'LCD Screen' but there simply won't come any image up.

I also have another 'test screen' from another old MacBook Air that I hooked up to the MBA and it's the same symptoms so I can exclude any screen failure.

Does anybody have any idea on that problem? I've read about this problem now a few times but nobody seems to have a solution. Is it worth trying to reset the VRAM or will we then just also loose control over the external screen?

Thank you for any suggestions!!!

 

Slowly please. The local Apple certified service dealer wouldn't have repaired it under warranty because there is a tiny dent in the cover that is way older than the hinges problem actually but they said the hinges are broken because you droped it so...

Repair price would have been $600,- the screen was $150,- I own an electronics company and am an electronic engineer myself, the decision was easy. I have access to tools and workspace, so even component level soldering solutions are welcome.

Any other thoughts more focused on my (technical) questions very much appreciado!! Thanks for your input!

 

No, unfortunately I don't have such equipment. The only thing that I can say is the for one of the screens I know for sure that it works because I took it off another Macbook Air a few days ago and I can see on the other machine (same model) that it is working. The screen bought off ebay is said to be 100% working from a 99.9% well rated seller - there's always a chance though of course.

I also think there is something wrong 'on the way' to the screen but as of now I have no clue as to where to start to search.

I could take it under the scope though and see if there are signals on the lpvs connector, though I couldn't tell if they are usable... but maybe a good idea!