Backlight doesn't work after repair

Display was broken and I’ve removed it. After I took new one and attached it, but the main ribbon (from display board to pcb board) was damaged. I’ve bought new and replace, but now backlight doesn’t work. Service man told, that problem may be in short circuit (when damaged ribbon touched metal tilting mechanism) and backlight is controlled by the BGA 8072PN (upper left corner of photo). But on the forum I’ve read that backlight is controlled by another chip. So I need to repair backlight but don’t know how.