what is an external monitor

[yeranny217]

Asus chromebook black screen

 

[COLGeek]

It is a separate display that you connect to the Chromebook to provide a second display. It can be a regular PC monitor or even a HDTV. What are you trying to do?

Also, on your Chromebook, you likely have a function key, that when pressed, will change the video output of your system (internal only, internal and external, and external only). If you screen had been previously working and you didn't damage the system, like by dropping it, then try using the function key to toggle the modes.