Thanks to everybody! Glad to find such nice healthy forum

Yes, this 780 has three ribbons from screen/digitizer assembly to motherboard. So should be easy fix.

Another funny moment - I CAN put this unit into calibration mode by holding left bottom corner of the screen and sliding power switch back and forth. So there is SOME life in digitizer. But that's it, I can't get anything else from it.

I took apart my 765 with hope to swap screen assembly to make sure it's digitizer's problem and not motherboard's. But 765 has just one ribbon coming from screen...

Oh well, at least I tried.

Thanks everybody one more time!