The laptop screen works normally but one or few colors are missing. All colors are displayed properly on an external monitor connected to the laptop. The colors are missing only on the laptop screen.
1. Poor connection between the video cable and LCD screen or motherboard/video card.
2. Defective video cable.
Possible troubleshooting steps and repair solution:
1. Try reseating the connection between the video cable and the LCD screen. Unplug the video cable from the LCD screen and plug it back in. Make sure the video cable connector is plugged all the way into the connector on the screen.
Check the connection between the video cable and the motherboard/video card.
2. If reconnecting the cable doesn’t help, try replacing the video cable with a new one. Apparenlty, the video cable is defective and has to be replaced.