To fix a display problem you may first try to restore, flash update the device firmware, unless the LCD screen panel is not damaged like cracked or broken. This may also fix the display problem for not damaged LCD screen module. For white screen problem, unless you can hear the device welcome tone when turning it ON, this problem is cause by either a faulty LCD screen or a display filter IC. So you may need to replace a new working LCD first, before you may proceed on PCB board troubleshooting.
Nokia E5 LCD Screen Display Problem Solution
The solution above shows the connection line paths of the display signals from the ESD-EMI filter IC down to the LCD pin connector. Which you can use to trace the the LCD displays corresponding line paths across to that circuit. You may first check the LCD's supply voltages on the upper components of the PCB board, also check or replace the resistors and capacitors. Then if the two supply voltages is okay. Try to replace the Display filter IC alternately.