Solved: as previous posters have mentioned, if the screen will not turn on after servicing the phone, disconnect the battery connector if you haven’t already. While still off, hold the power button down for 10-20 seconds, let go, reconnect battery and power the phone on. This works for many. If that still doesn’t work, as in my case, reconnect all connectors, and plug phone into a charger and then power on. This “fixed” mine, even though it had 70% charge at the time of repair. Good luck!