Chosen Solution

Hi, I have an iPhone 6 which does not power on. I’ve tried to connect it to itunes but it is not recognized. I swapped the battery for a charged one (nothing happened). I know the screen and the dock connector work because I connected these to another iPhone 6 I have and they seemed to work. What could be the issue? Am I forgetting something? What could cause my iPhone to not power on? Help would be appreciated! Thanks!

I don’t think there is much more you can do. You have ruled out a parts issue so now you know it is a board issue. There could be a lot of reasons your phone is not powering on. It will be very hard to diagnose the problem unless you have access to schematics and board view files plus the diagnostic and repair equipment like Microscope, multimeter, hot air station, soldering station, DCPS the list goes on not to mention experience in microsoldering and some electronics knowledge.