I purchased an early 2015 Air for its ssd from Craigslist for a very cheap price. Owner couldn't even get it to power up but I was interested in the ssd as that was the only part that looked unscathed. Battery doesn't work or charge when connected to the logic board. Owner said his autistic son got hold of it, had a violent outburst, and tore off the bottom and banged the air around. Unfortunately, I didn't save the pictures from the ad. I removed the 256 GB Samsung ssd and replaced the 128 GB Sandisk in my Air 2013. Luckily, I was able to restore my time machine to the Samsung and everything worked perfectly. I decided to try and test the Air 2015's other parts so I disconnected the battery, connected my charger, and it turned itself on after a few seconds and gave me the flashing folder with a question mark even though I placed my Sandisk ssd into the machine. I rebooted and held down the option key but got the padlock screen and a prompt for the efi password which I don't have. I contacted the seller for the password and I'm waiting to hear back. Regardless of whether I do or don't hold down the option key, the fan spins slowly when first powered on and will eventually ramp up to what sounds like full speed. Does the fact that the fan runs at full speed until I remove the charger inducate that the is something wrong with these sensors or is it an indication of another hardware issue? Any information would be appreciated. Thank you. Edit: the read and write speeds are 2.5 times better with the Samsung than the Sandisk.