This first solution shows the voltage supply to the LCD display module that feeds to the pin connector. You may check, trace this particular voltages first.this also includes the LCD display backlight LED corresponding current and voltage pin configuration. If this voltages are not present this will also result to display problem issues.
Nokia 5310 Xpressmusic LCD display supply voltage
And this solution corresponds to each and every LCD display data signals connection to the pin connector that being feeds from the application processor (CPU IC) through to the LCD display module.
All these lines is connected to an Filter chip resistors that have a resistance value of 33 ohms per each resistor.You may check, trace, replace this particular chip resistor if found damaged. And if found an open line paths, just try to manage applying a jumper wire on it for that is the only option.