Hi HW Tech:
Thanks very much for the detailed reply. I actually went ahead and tried it. The chassis is an A1278 MacBook Pro 2010 with an OEM 2.33 GHz / i5 logic board installed running MacOS “Mavericks”. Both the chassis and the original logic board were in good working order.
The replacement board was a genuine Apple 2.9 GHz / i7 logic board from a working (according to the seller) 2012 A1278 MacBook Pro running MacOS “El Capitan”.
The replacement logic board’s fit was identical to the OEM logic board’s fit. All 7 holes on the board lined up perfectly with the mounting points on the computer chassis. As mentioned in my original post, all the connectors and cables also lined up perfectly and every plug or connector fit into the replacement logic board just like they did into the OEM logic board.
I was encouraged by the seamless fit of the 2012 replacement board into the 2010 MacBook Pro. I did not have to force the replacement logic board to fit into the case so I’m certain that no damage was done to the logic board during the installation process. Given all of the above, I was really surprised by the results when I pressed the power button.
I got a completely black screen, no backlight, no sound and no indicator light (green or orange) on the MagSafe charging cord. Nothing, period. I was concerned that the 2010 MacBook Pro chassis was somehow responsible, so I uninstalled the 2012 logic board and reinstalled the OEM logic board. When I pressed the power button the laptop started up normally with backlight, Apple logo, progress bar, familiar Apple “bong” sound and appropriate lights (first green and then orange) on the charging cord. After startup the MacBook Pro ran and behaved normally in every way.
What I experienced with this replacement logic board failure appeared to me to be a power problem. I don’t have any reason for this happening. This is not the first of these upgrades that I have performed. I have the tools and the experience to remove and install these logic boards correctly. I performed an identical upgrade successfully just last week. The only difference was that the replacement logic board in that upgrade came from a mid-2012 A1278 MacBook Pro and I installed it into a mid-2012 A1278 MacBook Pro.
Would a firmware lock prevent the laptop form booting up at all? I am completely puzzled, so any additional insight or advice you or anyone else in the Apple Community can provide would be greatly appreciated.
Thanks!
Tony-P