Chosen Solution
Hi guys, I have a Apple MacBook Pro “Core i5” 2.5 13" Mid-2012 The problem with it is it won’t turn on or off by the power button. Symptoms are: It will only come on if I disconnect the battery and adapter and hold down the power button for a few seconds reconnect the battery and plug in the adapter, then it will start automatically.It will start if you then restart it. On the desk top.If you try to start it with the battery disconnected, you get the continuous three beep noise indicating bad ram connections (it has frozen before, crashed and gone to this state) Once the battery is completely charged it won’t start at all.
Your symptoms imply the logic board has problems. Did you have a liquid spill at some point into the system or sit it down on a wet surface? I think you’ll need to open the system up and do a full inspection of the logic board for any damage. Follow this IFIXIT guide: MacBook Pro 13" Unibody Mid 2012 Logic Board Replacement you should only need to go to step19. If you see any corrosion, staining, discoloration or burnt parts take some detailed pictures and post them here for us to see.
