it sounds like the power button needs to be replaced.
whether or not you can replace it will depend on how much gear you have to repair it and your experiance.
from the pictures on the teardown everything looks small so youll need to know how to microsolder.
also there is plenty of experience here if you do decide to try and do it your self.
if youre not confident enough to do those repairs then a shop may be able to do this for you!
good luck!