Hi @seanmcgowan
In order of best case to worst case possibility:
- Loose EDP cable connection on the motherboard or the LCD screen.
Here's the hardware maintenance manual for the laptop. Go to p.53 (59 of 66 pdf) in the manual to view the procedure to remove the EDP cable. This will allow you to check if it is still securely connected to the motherboard. On p.50 (56 of 66 pdf) it shows how to remove the LCD screen. You don't have to remove the LCD screen, just check if the EDP cable is secure.
- Damaged EDP cable where it passes through the hinge from the lower case to get to the LCD screen in the lid.
If the cable is damaged search online for 5C10S30543 (touch screen) or 5C10S30353 (non touch screen) to find suppliers that suit you best.
Here are some images showing the relevant schematic for the backlight power circuit and also the boardview showing the location of the fuse as it possibly won't be marked on the motherboard.
entire board view showing where the fuse is
zoomed in view showing the fuse location in more detail
(click on images)
- Faulty LED backlight circuit in the LCD screen.
If this is the case, the screen will have to be replaced as it cannot be repaired. Usually the Lenovo part number for the LCD panel can be found on the back of the panel. Search online for the part number, to find suppliers that suit you best. The HMM shows how to remove the LCD panel