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Hi, I bought a battery replacement from Ifixit for mid 2012 MacBook Pro retina.. All was going well until I followed the battery calibration process and let the power drain out until the machine shut down. After I plugged the power cord back in, the machine makes a kind of quiet rhythmic breathing noise but will not restart. The breathing noise sounds sort of like a fan starting to whir at startup but after a Half second then it slows and attempts to start again. This cycle continues on and on. Finally after a couple hours i unplugged i. that is the only thing that stops the rhymic very low sound. The sound starts again if I push the power button to attempt a restart while unplugged. Besides the problem of the machine not working, I’m also concerned that the calibration failure will effect the battery. Thanks for your help.
Try using an 85W charger instead of a 60W. The 60W charger is not designed for the 15-inch MBP.
It’s starting to sound like the battery or the charging logic on the main logic board is bad. Lets see if we can isolate which… Follow the guide MacBook Pro 15" Retina Display Mid 2012 Battery Replacement to Step 4 disconnecting the battery. Now with noting plugged in press and hold the power button for a good 10 secs. Then proping the system on its side so the MagSafe connection is on top plug in the charger, your system should then spontaneously startup did it?
