Chosen Solution
So almost 3 years ago, a friend gave me one of these to get some files off of it. They gave me a power adapter as I don’t usually work on macs, but it was in kind of poor shape. I plugged it in, and it didn’t power on. (I can’t remember the lights it gave me then, I was clueless about macs at that point lol.) I assumed the logic board was dead, and pulled the HDD and RAM and gave the friend her data back, and she let me keep the machine. Fast forward until a week ago, I acquire an Early 08 MBP without a power adapter. I’ve lost my friends power adapter at this point, so I buy a new one. It arrived today, ensured that 08 MBP worked, then decided to plug in this 12 MBP after nearly 3 years of being dormant, the MagSafe light turned orange, I press the power button, it gives me the beep code for no RAM. I put in some ram from a broken Toshiba I got a while ago, plug it back in, light turns and stays green, does not power on at all. I’ve tried an SMC reset, and nothing happens. After a while I was troubleshooting, i had the back cover off, plugged in, and I’m looking at my phone, all of a sudden, the MagSafe light turns orange and it turns on, boot chime and everything, then it turns back off and the light turns green again. I’m not well versed in Macs, but I’ve heard the MagSafe board isn’t uncommon to go bad on these. Is this a symptom of a bad MagSafe Board, or is there some weird problem with the Logic Board? Update (10/03/2021)
I went ahead and tossed the hard drive back in (I still had it lying around and it has Sierra on it) to see if it actually would boot. For some reason, the screen doesn’t work, and the keyboard doesn’t seem to work either. But I managed to get it to power on, plugged in an ethernet cable, and Lowe and behold, it showed up on my Network! (At the time of screenshot, no other macs were connected) Thanks! -Robie
OK, the blinking LED’s is telling me the battery is shot as well as the single LED when the charger is disconnected. You need to get a new battery first to get over that hurdle. MacBook Pro 15" Unibody (Early 2011-Mid 2012) Battery and here’s the guide to put it in MacBook Pro 15" Unibody Mid 2012 Battery Replacement
