LCD screen cracked, how to distinguish what is the external screen or the internal display bad

Users questions: I have a Noah NP1200, recently it has been my screen fracturing, but does not affect the picture, just looks like a cobweb, then there is the touch screen fails, but sometimes use a pen to scribble on it, the machine has a written response, may I ask what is the external screen or internal display is broken it?
Experts answer: when However, the external screen is. If there is no internal screen displays.
  • This information provided by the users.Thanks!