This guide may help you out if the LCD screen shows a dark screen and or the keypad white LED are not functioning. The solution below shows the connection line paths of the LCD and keypad backlight LED of Nokia C2-00 PCB board. You can easily trace and locate where the possible problem occurred.
On Nokia C2-00, the keypad and LCD white backlight LED were connected in series, so it means if there is one LED is busted the whole backlight circuit will shutdown. For easy troubleshooting, you may first check both of the white LED on keypad, then check also the battery power voltage (VBAT 3.7V) connection.
The LED driver circuit will be the next spot, then check all the corresponding LED+ and LED- connections down to each of the keypad and LCD white LED.
Nokia C2-00 Keypad and LCD Display Backlight Connection Tracks