Chosen Solution
I replaced the battery on an iphone 5s using the ifixit kit. Everything is working fine except the power button. It clicks but the phone won’t turn on/off. Any ideas?
First of all, double check if the volume button + power button ribbon that goes under the battery at the upper part of the battery is plugged into the connector on the logic board. The power button + volume cable ribbon is most likely damaged from when the battery was being pryed up near the top left part. The only way to fix that is to replace the whole volume + power button ribbon cable. You can get the part from here: iPhone 5s Audio Control and Power Button Cable Guide to replace the part: iPhone 5s Upper Component Cable Replacement
Solution was to simply set the hour and date, by connecting it to iTunes.Same problem here, but solved
Better to start to power on using the line No7 / at j2 connecter (short with ground using tweezer), if power on , then change the power switch flex cable , if not working then check line 9 volt , it should be 1.8 v and if not check the line from AMBER PMU to the connector , following pics of mine will help:
