MacBook will not power on when logic board is fitted to chassis
i just received a 2011 mbp13 2.3 i5 model, exhibiting no power whatsoever. not even magsafe when connected.
i pulled the logic board, cleaned thoroughly and added a new DC in board.
testing the new DC in board outside the chassis, i got (at first dim, and then full) green LED at the magsafe. i plugged in the fan, and sure enough the mac was powered on. i pulled the plug, reassembled the laptop, and there's no power whatsoever again.
then, lifting the logic board out while still connected to DCIN, i can power on the laptop. furthermore, i can place the logic board in the chassis and it remains on. if i pull the plug, i cannot restart the mac without removing the logic board.
if i remove, power on, then install the logic board, i can connect the battery and cables and begin to charge. i connected the keyboard, powered off the mac, and the magsafe remains orange. i make all the appropriate connections, and power the mac back on.
everything works, and i'm installing sierra.
the second i remove the magsafe, i'm back to square one and must remove the logic board to power it on again.