My son's e series laptop has developed a fault whereby the display has a flickering image in the bottom third of the screen that is a copy of the full screen display and it has a slightly pink hue. Almost like a v-synch problem on an old CRT TV. It is present right from initial power up so I don't believe it is a Windows (8.1) problem, but I checked the drivers anyway. When I connect an LCD TV via HDMI the picture on the TV is perfect (whether in clone, extend or TV only mode). In all cases when the laptop screen is on, it flickers. Moving the lid ( a la broken wire) doesn't alter the fault.
From the above I believe there is a hardware fault after the graphics processor to the laptop's LCD. I have run diagnostics but no faults have been found. Is there anything else I should try before taking it in for repair?