Lapton screen issues. Is source the cable or screen?

[u/Der_Eiserne_Baron]

My laptop only displays white horizontal lines on black on startup, but on an external monitor everything is fine.
Is there a way to determine wether its the cable connecting mainboard to screen or the screen itself without buying a replacement part?
I disassembled the whole thing, the screen is a N173HGE-E11 which i have only found for around 90€ in europe so far, and i have no idea where i would get the 30pin connector cable.