Broken on/off buton

Hi, my phone fall and since my on/off button doesn't work anymore, I try twice with two different shop to repair it. The first one opened the phone to check the part but it seems that there are no damage apparently. I bought the part on "Asus Part" web shop and the second professional replace it but it doesn't change anything, even with a new part it doesn't work either. The professional think it can be from the motherboard ...

I am desperately looking for a way to repair it because if it shut down, I have no way to make it power up without the button ...

Thanks in advance for any help.