Can't unlock screen, display not waking up

Hi Jan,

There's honestly not much connection between the charging system and the display system on an iPhone, so from an electrical engineering point of view it doesn't seem likely there's a correlation between the two. From a software viewpoint, who knows what evil lurks in the heart of Apple Inc.?

The power button is pretty simple; either the button is pressed or it isn't. So if it works under one set of circumstances then it pretty much always works under all circumstances. Given that I'd say it's most likely not a hardware problem.

Which means we should really be looking at software as the most likely cause of the problem. I'd suggest backing up your phone and doing a full restore with iTunes. If you want to really get down to it, look up DFU mode and do the restore that way; it's the most complete software update possible.

But yeah, you want to eliminate software as the source of the problem first before trying to throw hardware at it. So try a restore and let's see where you are after that.

Given the age of your phone, it's quite likely the battery may be getting tired and ready for replacement. There's an app for your computer called Coconut Battery that seems to be popular among the repair technicians who frequent iFixit, so it might be worthwhile downloading it and using it to check the status of the battery on your phone. If your battery is having issues - and it sounds like it may be - the app will give you a good idea of whether it's time to replace it or not.