Chosen Solution
I have an iPhone 6s. It would only charge if I bent the lead so I ordered a replacement charger port. I stripped the phone and fitted the new part but now my phone won’t turn on. Well, I think it’s on because I hear alerts but nothing on the screen. I thought it may be a problem with the screen but nothing shows up in itunes either. If I hold home/power itunes then says it needs to update. I updated it and it says it would show after update/reboot but doesn’t.
Were you careful to disconnect the battery before reconnecting the screen? I’m going to guess “nope, didn’t know you had to do that” in which case this is classic iPhone 6s backlight problem. Head to your friendly local microsolderer or mail in repair service to get your logic board fixed up for blown backlight filter.
Jessa