My iPhone 6 Plus won't turn on at all
I have this iPhone 6 Plus that refuses to turn on. So far I've replaced the charging port and the battery and it still won't turn on. iTunes does not recognize it either. I tested the logic board through the FPC Connector using a multimeter and the reading gave me a voltage between 3.5-4.0. According to a YouTube video, this means that the logic board is still alive and the logic board can be charged.
However, iTunes does not recognize the device and my it won't turn on either. What else can I do? What could be the issue?
Thank you in advance!