If ever encountered this kind of problem you may first try to update or restore the device firmware first, and then try to install a new replacement LCD screen module.
If all of the above already been done but still the problem still exists, you may then used tjis solution below for hardware troubleshooting procedure on Nokia 2710 PCB board.
Nokia 2710 Display problem solution -hardware repair
You may start checking up the nokia 2710 LCD pin connector, ensure that is absolutely clean.
There are two resistors mounted at the bottom of it, check this two resistors resistance value for it holds the display data signals through to the LCD screen. Replace if found damaged.
Check also the LCD screen module supply voltages, these are 2.8 and 1.8 volts.
If both resistors and supply voltages were okay, you may then suspects that the problem lies on the JUNO chip. Reworking this chip might possibly fix and repair Nokia 2710 display problem issues.