Late 2016 MBP, MacOS10.13.4, Radeon Pro 460 4096 MB
Over a week ago, my inbuilt display stopped working. Specifically, only the top quarter inch worked. After a few reboots and connecting/disconnecting an external display (which works fine), the main display comes back up, and continues working.
Fast forward to Wednesday. Problem re-occurs. No amount of rebooting/display switching works. Do the NVRAM/SMC resets. Boot into Recovery mode. Nothing fixes it. Take it to the Apple Store, show the symptoms, and they're all, "We can replace the display for too much money to be worth spending on a nearly two year old laptop."
I postpone it, because I need to do some work this weekend. We close up my laptop, and I go home.
And here's where it gets weird. When they were inspecting my laptop, they plugged it into an ethernet cable and did something to force it into an in-store diagnostic mode. In store the display continued to not work. But after folding it up and walking home, when I opened by laptop the display worked. I could see the weird purple cube icon, but it wasn't accepting any inputs from the trackpad or keyboard. When I rebooted, I was back to "top quarter inch only" mode.
But the fact that it displayed at all implies that it isn't a hardware issue. I've reinstalled the OS and done a disk repair, just to eliminate anything there.
Other weird symptoms:
- When I don't have an external display attached, the onboard display only shows the top 1/4"
- When I plug in an external display in "extend my desktop" mode, it continues to display the top 1/4"
- When I plug in an external display in "mirror desktop" mode the onboard display goes completely dark
So, in addition to any tips/advice for this problem, if anyone knows how to put my Mac into the in-store diagnostic mode, that'd be super helpful too, because I'd like to confirm that it re-enables my display.