Black screen but powers up

My laptop broke over a year ago and I only just got round to fixing it today. The oringial problem was that it wouldn't charge. Today, I have taken it apart and found that the wires connecting the charger port to the circuit board had broken off. I soldered them back on, put it all back together and sure enough it started charging again! Yay!!

Now theres another problem though! The screen won’t come on. I've taken it apart again, checked the LCD cable and it seems fine. I've also tried plugging it into an external monitor but that didn't make any difference. I cant understand why it's not working.

It seems to power up fine, makes a little “beep" all the LEDs light up as they should but just nothing on the screen, just black. Any ideas?