If the newly installed LCD still shows the same problem, refer to the solution below and locate the highlighted components on the C3-01 PCB motherboard. These components holds and control the LCD LED backlights to work.
Nokia C3-01 LCD Screen Display backlight LED Problem Solution
Check/ replace the highlighted components such as the filter coil, diode and transistors. Check the battery VBAT voltage 3.7V across the inductor coil.