Default xperia z1 black screen of death

Long story short the screen never turns on, theres a tiny bit of backlight though and apps are working in the background. I've tryd updates and so on, nothing fixed it.
So my final resort is to change hardware parts...
The thing that i think the problem is, is a faulty motherboard. Is there any way in particular that i can try to test and make sure that the screen really isnt the problem here?