Logic Board Late 2011 Macbook Pro
Went to the apple store to run diagnostics on my 15" late 2011 Macbook Pro had a litany of questions and yet forgot about some key issues. If anyone out there can answer my questions I would greatly appreciate it.
My model macbook pro is subject to the faulty logic board, apparently due to the lead free solder used which cracks due to heat. Without the magsafe plugged in, it simply shuts down. I had to replace the logic board in 2015 and worked fine up until a few months ago. Apple said the same thing is happening now. At first they thought it was a problem with Sierra OS and wanted to wipe the laptop and reinstall the OS. Same thing is happening in now with High Sierra. Apple genius said my laptop could not initialize with high sierra or sierra, had to take it back to El Captian. Two options, buy a new macbook pro or replace the logic board through a 3rd party because apple no longer has parts for my 2011 MacBooks Pro.
My questions:
1) Apple replaced the logic board and the same issue happened again although not as bad. My screen does not get glitchy, the computer simply shuts down if not plugged into the magsafe. Even if I find a new logic board for my 2011 macbook pro won't the same problem keep persisting due to the faulty lead free solder? Should I just buy a new laptop and save the hassle?
2) When my macbook pro is plugged into the magsafe it does not shut down unless I shut it down, it functions fine which is why I assumed it was a battery issue and not the logic board. But system information and apple store diagnostics say the battery is fine. Battery cycle count is at 1840, condition: normal. So why does the logic board functions fine and my laptop not shut down when the magsafe is plugged in, yet when I unplug the magsafe it shuts down after about a minute and a half? Is that part of the logic board problem or a battery issue? Again, Apple diagnostics showed that the battery is fine but logic board showed a yellow exclamation.
MacBook Pro, Mac OS X (10.7.2)