HP Probook 640 G2 blank screen problem

[soma64]

Hi friends!

I've encountered a problem with my HP Probook 640 G2. The screen is blank and it doesn't seem to work. The laptop screen and cable aren't faulty, I've connected them to an another notebook and they work, but if I connect a different, perfectly working screen and cable to this laptop, it doesn't work either. If I connect an external display/monitor there's an image, but the notebook screen itself doesn't. I think the problem might have to do with the LVDS port (40 pins). I cleaned the LVDS connector on motherboard and it seems fine, it didn't solve my problem. The screen, mic and webcam all share this connector, but I don't know the pinout. I compared it to other notebook connector pinouts and it isn't identical to any of them. The 3.3 V can be detected on the connector, so the non-existent lack of it can't be a problem either. There's a 21A40 marked 5 pin IC near the LVDS connector, which I assume provides the 3.3 V, and it indeed does. (I couldn't find this IC in the catalogue, but I believe it has a similar function to SY6288 which is a low loss power distribution switch ) First I assumed this was the problem, but because of this it can't be. I would appreciate a lot if someone could send me the pinout of this LVDS connector, it would help me a lot in finding the problem. Or if someone has the schematic of the notebook or any idea I'd greatly appreciate if they could share it with me.

Thanks in advance,

Soma