If encountered a dark screen display or backlight LED failure on Nokia E72, you may first try to replace the LCD screen module, to confirm if the backlight LED's is still working or not.
If the newly stalled LCD screen display still shows a black or dark screen, the problem this time may lies on a faulty components that drives the backlight LED to light up. This solution below shows the connection line paths of the LCD backlight LED of E72, you can use it to trace and check particular components that holds for display back lighting.
Nokia E72 Display Light Jumper Solution
The components highlighted on solution above shows the display backlight LED connections. These components were composed of an inductor coil a diode and a filter capacitors. You may then check the 3.7volts battery supply voltage that is also needed in the circuit. You may also trace the corresponding negative and positive supply voltages line paths of the backlight LED through to the corresponding LCD pin connector where it is being connected.