Chosen Solution
Why Does my screen blink intermittently? APPLE CANT FIGURE IT OUT!! I’ve had this problem come up recently. This was a problematic MBP mid 2012 The Logic board was replaced in warranty as one of the memory slots doesn’t work so running single slot. Symptoms: Screen blinks to black and the ability to move the mouse in that instant is lost.Screen blinks on battery and magsafe powerNo change with movement of the LCD screen Update (10/10/2017) Here are two video clips. One of them shows how it blinks when I’m using it, and the other shows it blinking on the reboot page.
Apple can’t figure it out because most of their “Techs” are completely clueless. More than likely, the displays LVDS connection on the logic board is making intermittent contact.
You can fix this with a Phillips screw driver. Open up the bottom following this IFIXIT guide: MacBook Pro 13" Unibody Mid 2012 Lower Case Replacement. Having the system in front of you with the battery at the top and the fan at the bottom, Look in the lower left corner. You will see a gold/silver plug. Pull that out toward’s you. Then plug it back in (keep it flush on the logic board). That will probably solve the issue. Lets not get too in depth until we do this.
No, this is a hardware issue not software. OS or driver failure wouldn’t react this way. Diagnostics have limits on what they can test. As you can’t test your system via an external display as the port is bad I’m thinking you have a logic board issue Vs a screen here. I would go back to Apple and focus the repair on the Thunderbolt port which should resolve both issues.
Shut down computer.Power off 2nd display.Power on computer.Wait for the boot to finish.Power on 2nd display. This works for me on a trash can mac pro late 2103
