Dropped iPhone 5s dead, motherboard problem

Hi there.
A client brought a dropped iPhone with broken screen.
Put the motherboard in a new working case and not even starting.

Since there is no short on the battery connectorand no missing component after inspection I guess something some ball from a chip must have desoldered… would you guys make that assumption?

If you had to start checking lines… what line and ic’s would you check first?

Also one question… have surfed through the site and found many useful squematics for all iPhone versions but i never found information about theatrical voltages and test points on the boards. Is that information available somehow?

Thanks a lot.