Solution For Gadget

Heres a solution that may possibly help fix and repair Nokia X3 Failure of LED backlight  on keypad and LCD screen display. This solution completely shows the lines paths and particular components that may need to check and replace if the LED backlight failed to light up.




There is a fusible resistor is been connected to the LED backlight circuit in case a short circuit occurred if the device is being damaged by a liquid (Wet Damaged). See solution above marked with number 1.
That resistor is the one feeds the power supply from the phones battery.
If that resistor is open both keypad and LCD display LEDs will not light up for it is the main LED supplying positive voltage.
The negative current or voltage has two circuits, one for the LCD (marked with number 4) and the other one is for the keypads (marked with number 3).
You may check / replace each particular corresponding  connected components highlighted on the picture for further troubleshooting.

Heres a full solution of Nokia X6 keypad problem and failure. This solution shows the complete line tracks for easy tracing particular keys that stop responding including the camera and volume control switches button.



Each key were group in one line of connection, each connection is filtered by an ESD filter IC. The solution above shows how each certain keys are being connected to the keypad filter IC. There are three keys commonly connected together in one line of connection, therefore if only one or two key is not working, you may consider that the problem lies only on an open path of connection. If there are three and above keys does not work you may considered that the keypad ESD filter is damaged or faulty.