Display brightness goes down and becomes zero

Hi i have an acer traveler laptop. It was until today morning. All of a sudden since morning i can hardly see the display its too dim. I dont whats the reason behind that. I connected it to an external monitor i can see the display fine and it works fine . Can anyone help me ????? I think its the problem with the video chord .. What say??

 

Ya i thought the same it might me the problem with graphics chip and i checked the brightness its perfect. Can i replace the graphic chip itself is it possible for laptop monitors ??. How to find out the configuration of existing graphic chip on my laptop so that i can order same new one.

 

how can i replace the back light in the monitor.. Is it possible .. The screen turns into orange background screen and it goes dim withing few minutes. So do u think i can replace the back light in the monitor if yes how can i do that plezzzzzz help me out...