My MacBook Air won’t power on

This may require some additional diagnostic steps. It’s possible you have a bad battery. These batteries are relatively easy to remove. If you have a friend with the same model machine you can ask to try their battery in your system. See this guide for battery replacement steps.

It might also be a failed IO board (the component which houses the MagSafe 2 port, USB-A port, and headphone jack). You can see the steps for replacement here. Before trying that replacement it might make sense to test the voltage passing through the MagSafe 2 port. You can do this by using a multimeter to read the voltage. Set the multimeter to read DC voltage. Then connect one terminal to the pin circled in red. Connect the other terminal to the pin circled in yellow. Be careful when doing this and keep your hands steady (if you connect the wrong pins you might have a spark). Record the reading on the multimeter. It should be around 14.5 V for a MacBook Air (it doesn’t matter if it’s positive or negative, that depends on the pin configuration). If it’s less than this the IO board may need to be replaced. If it’s more than this the logic board may have a short which is causing it to draw too much power.

Hello Robert!

Inside your computer is a small button battery which is used for the CMOS, or BIOS. If that battery dies it will cause all sorts of problems like not starting up, starting up then shutting off, etc. Usually replacing that battery will take care of that problem.

If that doesn't work your main battery could be going bad. Bad batteries cause all kinds of problems, it doesn't matter if its in a car, a phone, or a computer. Check both those batteries out and post back with an update.

Best of luck.

Eddie