Chosen Solution
My Macbook Air suddenly turned off with 75% battery life and hasn’t turned on ever since. It hasn’t suffered any damage from falls and it has all of its original parts. I also ruled out any software problems. I considered the problem being the Logic Board hardware, but I also noticed other strange things. The charger LED turns orange as if it was charging, but it never finishes charging the battery. Therefore, the battery is not charging. Also, the computer won’t turn on after I disconnected the battery and only connected the charger. Could a faulty I/O Board have caused a well-functioning Macbook Air to shut down without warning and not reboot? Also, since the battery isn’t charging, could the problem only be the I/O Board? Or could it be the Logic Board? Or both?
Does the magsafe light go green then orange again when you press the power button (with charger plugged in)? A DC-IN (Magsafe) board can cause it not to turn on, though it can also be the logic board too. In most cases it is caused by liquid damage on the board, and most of it can only be seen under a microscope. You will probably have to end up taking it to someone that repairs liquid damaged Macbooks as they know how to diagnose problems like this well.
