How can I replace the motherboard of my iPhone 5s?

"Hello,

You can absolutely replace the motherboard in your phone but it is only worth it if all the other components are functioning properly.

You will pretty much need to tear the phone down to get the motherboard out but it can easily be done by a professional, and replaced by a professional.

Your phone is not a total loss.

John Device Savers"

You can remove find your iPhone on your PC. Log in to iCloud.com on your PC and find your device to remove.

First, the motherboard/logic board contains all the information. Secondly, you can switch the motherboard/logic board if it's dead for a working one. If you're still under warranty and haven't repaired/opened the iPhone just take it to apple and they should replace it. I do also think the touch id/home button is unique to the logic board (not sure). If you do switch out the logic board make sure to log on to icloud.com, sign in and erase all data from the logic board you took out so your stuff won't be saved on it. Hope this helps.

where can i get a new motherboard for my iphine5s

If you want to replace the logic board you can use this guide: iPhone 5s Logic Board Replacement