iPad air lỗi công tắt từ 
step 1: measure here, if doesn’t have resistance -> tracking to line and lifting wire (yellow frame) on line.
step 2: If shorting ->remove capacitors (purple frame).
step 3: measure 2 sides of this wire, if 1 side has resistance, and 1 side hasn’t -> take off and jump again. If fully lost resistance -> take off IC source and lifting up.
step 4: replace IC (orange frame).
step 5: If voltage 3v weak or non-signal ->replace IC source.
Note: Most of them were error at home line. Case on main just happen in error IC (orange frame), or the wire (yellow frame) supply voltage 3v to socket break.
step 2: If shorting ->remove capacitors (purple frame).
step 3: measure 2 sides of this wire, if 1 side has resistance, and 1 side hasn’t -> take off and jump again. If fully lost resistance -> take off IC source and lifting up.
step 4: replace IC (orange frame).
step 5: If voltage 3v weak or non-signal ->replace IC source.
Note: Most of them were error at home line. Case on main just happen in error IC (orange frame), or the wire (yellow frame) supply voltage 3v to socket break.