Dim LCD screen

[wizardtres]

I just bought a used laptop and the LCD screen is quite dim compared to my other laptop and desktop computers. I hooked an external monitor and everything looked nice and bright. Other than it being dim the picture is clear, it does flicker if you go to open or close the LCD lid. What can it be? thank you.

 

[Tmagic650]

The LCD panel or its inverter could be bad... This also could indicate a damaged LCD to motherboard cable