Chosen Solution
I have a iphone 6 with a battery that exploded and a broken screen, I replaced the battery and screen but it still doesn’t turn on
If you have a multimeter, start by chemcing your battery voltage. It should be at least at 3.7V to turn the phone on Do you have a usb amp meter? If not, then connect it to iTune to see if the computer detects it. If so, then you know the phone is at leadt turning on and that you have no image instead. Let us know what you find
I left it to charge for a while and now it works fine!