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My macbook spontaneously died two years ago, it wouldn’t charge, the magsafe green light wouldn’t turn on when plugged into the computer, so I waited until I could get a new battery. I recently got a new battery, I installed it pretty easily, and it turned on, it had a residual 12% charge on the new battery! I decided to charge the battery because it was low, but when I did, almost immediately after plugging it in (the magsafe green light lit up for the first time since it died years ago), it started to smoke near the charging port–then it shut off and the screen turned black. I disconnected the charger, I tried unplugging the new battery and plugging it back in, but to no avail, it won’t turn on. I don’t know what it is, I’m not a computer expert and it’s kind of old, I have no clue what’s wrong with it. For a moment when I installed the new battery, it worked perfectly, it wasn’t until I plugged it in did things go south. My magsafe is a 60W, the original one that came with my computer. Help!
Sounds like you had a short in either the MagSafe connector or the I/O board. Review this Apple T/N to make sure your MagSafe adapter is in good shape: Apple Portables: Troubleshooting MagSafe adapters Make sure the cable is not damaged or has any twists (bumps) as it can short out. Within the system you’ll likely need to replace the I/O Board. Follow this IFIXIT guide: MacBook Air 13" Mid 2012 I/O Board Replacement and here’s the needed part: MacBook Air 13" (Mid 2012) I/O Board
