If you can get it apart, it might be just one of the 'zebra strips' needs a clean. These are strip of alternating slices of black conducting and white insulating rubber that sits between the glass of the display and the circuit board behind it. There is usually two, one across the top and one across the bottom. If you can get all this apart, you can give the strips and their mating surfaces a wipe with contact cleaner or similar. While it's in bits, check any solder joints for cracks etc.
Otherwise, I'm sure a scrappy will have one.