Chosen Solution
I have replaced everything I can think of to replace other than the motherboard and this iPhone 6 plus it has a brand new digitalizar it has a brand new battery brand new power port Charger brand new charging cord and charging Outlet it has brand new camera brand new power main home button everything I have tried to do to this iPhone 6 plus I can still not get it to turn on
There is always the possibility that some of the replacement parts you used were defective themselves. That is not an uncommon occurence. The only way to troubleshoot a phone is to use known-good parts. That can be difficult for a DIY repair. Assuming all the parts ARE good, then you have a logic board issue. This would require a micro-soldering repair and is not typically DIY.
If you’ve tried all the parts in another device and they work, then it would appear that the motherboard is the problem. Have you tried checking to see if the device is stuck in DFU/Restore mode? I’ve come across a few devices where they appeared to have no life at all. And after a few attempts of holding down both the power & home button, and releasing the power button after 10 seconds, the device turned on. It’s best to do this while the device is plugged in to iTunes with the volume on the computer up, so you can hear if the device is connecting/disconnecting from the computer.
