Hello I seem to be having the same problem.
What happens is after a while the screen will flicker, and then go black.
No matter what I do, I have to power off and back on again.
NP940z5l model , Samsung Notebook 9 Pro.
the gpu is soldered into the motherboard so there's nothing you can do on your own, if you're in luck and live nearby one of Samsung centre repairs than send it in....Mine is collecting dust in the corner:/
Yes I can. Just as an FYI, I did an online chat with Samsng tech and they changed some things on the display settings. Did not work as I have had two black screens,
Would like the problem resolved as this machine is very nice and quick and I love it.