IPhone won’t turn on

Apple iPhone 6 won’t turn on, changed screen, and battery. What else?

Repairing an old iPhone requires patience when you buy an old iPhone that is not turning on. Several solutions

1- Change the screen, make sure that the screen is working on another iPhone.
2- Change the battery, make sure that the battery is fine too.
3- Change the charging port for a new or old one that works too.