Strange Mac Monitor Shenanigans

July 27, 2017 10:19 AM

This is not what my Apple LED Cinema Display should be doing. It's hooked up to my mid-2015 15" MacBook Pro. I unplugged the monitor, and the laptop display showed black. I force restarted, and all is well. Should I worry about the external display, the macbook, or the cables? It's only happened this once (so far).

I should note a more chronic problem with the same setup.

Whenever I restart, the "choose your account" screen looks fine, but, immediately after I sign in, the screen does this. Workaround is to briefly unplug/replug the minidisplay plug (into the macbook's thunderbolt 2 port), which always fixes it.

This problem, obviously, is only on monitor, not on Macbook.

posted by Quisp Lover to Computers & Internet (3 answers total)

Run it through an Apple Hardware Test both plugged in and not. It would be helpful to see if another computer behaved the same way on the monitor, but assuming that's not possible, I'd see how it runs the test and go from there. Same thing with trying a different monitor on the Mac.

If I had to guess I am going to say video card, but I'm not confident in the guess without more data.

I'd not worry too much if it was the first time. I'd just make sure I have good backups (always the plan!).

On the bright side, if it is video, those problems only get worse with time, so eventually you will know what it is (if it's anything).
posted by cjorgensen at 11:11 AM on July 27, 2017

Response by poster: Apple Hardware Test is for Macs from 2012 and earlier. I ran Apple Diagnostics both with and without monitor attached, and it reported both problems.

Since the chronic issue is monitor-only (not sure about this latest fleeting issue), and the monitor is eight years old, and I've not had any problems with the MBP's screen, I'm gonna guess that my Apple LED Cinema Display is nearing the end of its life-cycle.
posted by Quisp Lover at 12:34 PM on July 27, 2017

I know there were some firmware update for Apple monitors. See this page for some info.
posted by Cranialtorque at 8:37 AM on July 28, 2017