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During normal usage (surfing internet / email / etc) not connected to power adapter, the screen went black. For the life of me, I can’t remember if everything stopped at that moment, or if it was just the screen, and in turn if I forced shutdown or if it shutdown on it’s own. I hit the power button to boot and I hear the chime, but I do not get any backlight on the screen, no backlight on the keyboard, no lights (cap’s lock) on the keyboard. I know the keyboard works because it is registering me resetting the SMC and PRAM. I will hear the chime every time the PRAM is reset or the computer is turned on. I have tried letting the computer stay “on”, as confirmed by fans running, to completely drain battery. Tried connecting computer to adapter and resetting SMC and PRAM then, but still no backlights, no video, nothing. I have also tested connecting the computer to my thunderbolt display via thunderbolt port as well as an HD TV via HDMI port with nothing going through. About a month ago I replaced the battery. Nothing was out of place and everything was working perfectly until today. I have also opened up the computer to make sure all connectors were good. Any other ideas of what could be going on? I have an idea but don’t want to lead my question either.
OK lets try one last test: Disconnect the battery and then with the battery and MagSafe disconnected press and hold the power button for a good minute. Then plug the MagSafe charger in your system should spontaneously start. Your MagSafe chargers LED should be Amber. If this fails your logic board is in need of serious repairs, it maybe easier to just replace the logic board. Review the guide here for your board MacBook Pro 15" Retina Display Mid 2012 Logic Board Replacement
Any solution to this problem.. i have the same issue
