LG TV backlight

[lew247]

50LA620V   the picture and sound it working perfectly
The problem is there is no backlight on it at all, the screen is totally dark, but if I get close enough to it I can see the picture perfectly, it just has no light at all
Do I need a new ccfl or could it be the inverter that the problem is?

Also
Any idea where I could find a service manual for this tv please?