Look for cables that run from motherboard to display. Change those.
I have an Asus G550jk, bought in 2014. About 15 months ago I had issues with my screen cable: the microphone stopped working, I got flickers when tilting the screen and eventually the screen image died and I had a faint image when strong light hit the screen. I changed the cable and everything was great.
A couple of months ago I noticed this issue: say my screen would be open 120 degrees from keyboard, when closed to 60 degrees ( about there ish) it would go totally dark instantly, no faint image with strong light hitting the screen, sound and computing still working. No matter what I did, swing the lid back and forth, press keys, nothing recovered it except closing the lid fully and opening it again. So, I would go in sleep mode and wake it up again then I had image again.
This issue was present both in Win 8 and 10.
Occasionally, if I opened the screen fully, about 160 degrees, the blackout would happen sooner at about 80 or 90 degrees, at least I seem to have noticed that - so there's something mechanical about it: probably the same mechanism that puts the laptop to sleep when the lid's closed (except my laptop wouldn't go to sleep, just a dark screen so I'm not sure).
Finally, a few days ago, while watching some clip online, I got this yellow screen of death, with error 21 ( 20 something anyway), sound looping like a jammed video. It kept looping so I forced shut-down.
At reboot I saw the boot log info and Asus logo, then total darkness. Subsequently I did not see anything else when restarting. So now I'm in total darkness.
I suspect it's not the cable as there were no flickers - i.e. the issue I had 15 months ago.
The laptop works just fine with an external display via hdmi.
So what do you think it's broken? Lemme know as I'd like to buy the part and change it asap.
Thank you,
Andrei

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