Why will the MacBook not power up sometimes?
I have a 13" Unibody Mid 2009 MacBook Pro that will not turn on most of the time. It will charge and show a charging indication with the battery LEDs. It works perfectly when turned on, it restarts fine.
I received this from a friend to fix, it turned on immediately for me when I connected it to MagSafe connector. The next time I shut it down was right before I returned it the next day (after upgrading it from Snow Leopard to Mavericks). When I arrived at my friend's house, the MacBook Pro did not start back up. So I took it back for further diagnostics. Sometime on my way home while the MacBook was in it's box, it turned on. I believe this to be the case because I immediately opened it up when I got home and saw the login screen instantly when opening the display. This was very strange behavior. I have never seen a MacBook spontaneously turn on (like an iMac after a power outage). I'm not sure how to interpret this since the battery connection appears to be fine and has been reseated the day before.
Initially, I thought a problem was with the power button, but jumping the power pads on the logic board didn't work either. I was able to shut down the MacBook and restart it two more times without any problems after I got it running again.
I returned it again and suggested that they let it sleep and never shut it down completely. They did not heed my advice and shut it down that night. The next day it would not power on.
The battery shows a full charge and tested to last more than 2.5 hours of constant use unplugged. It does not matter if the MacBook is plugged into the MagSafe connector or not, the problem exists the same. I have also tried removing the battery and turning it on with only the MagSafe power cord as the only source of power to rule out the battery as the source of the problem.
What could cause this intermittent failure to turn on?