iPhone 7 Power button not working, all other buttons work fine.

Hello,

I have a iPhone 7 which I want to get out for sales but currently the power button isn’t working. I have replaced the side button flex cable twice now and still having the same problem (Yes i made the whole effort to simply swap them out completely without testing because i thought they would work for sure. stupid, but that’s what i did.) So now i actually decided to just plug another new flex cable in and use a small tool to press the button to see if the phone starts, and it does not start.

I dont think 3 of my flex cables would have the exact same problem including the 4th one that was already in the phone when i got it.

So to my question, is there anything else that can cause this problem? is the PCB broken somewhere? the phone boots perfectly fine when i plug a charger in and everything except the power button is working fine. I also feel like it’s weird that the other side buttons work but the power button is the only exception.

Note: I have updated the phone to the most recent IOS update and made a factory reset. didn’t really thought it would make a difference but still gave it a shot with of course no success.