Here's the Nokia E5 solution for not working LCD screen display backlight LED problem that result to a black or dark screen display problem. The following repair guide shows the connection of the LCD displays or LCD panel backlight LED.
This may help for quick and easy repair for not working LCD backlight problem. Just ensure that the LCD is not damaged like broken or cracked, for you may need to buy a new LCD display for that matter. Just refer to the solution below if after ensuring that the LCD is still working and only the light won't glow up.
1. First try to replace the LCD screen display module.
2. Check the LCD pin connector, clean, re-solder it if necessary.
3. Check/read the VBAT voltage across the inductor coil, check the inductor coil too, replace if found damaged.
4. Trace the connection line paths of VLED-, VLED+ and the switching line.
5. Check/ replace the resistors near the LED driver IC.
6. Rehot, rework or replace the LED driver IC.
That's it, hope this may help... Enjoy!