My friend spilled a very small amount of watery soup into the keyboard. roughly on centre. after unpluging everything and leaving to dry thoroughly the laptop mow works perfectly with exception of backlight.

I.e. It works perfectly on an external display and also you can use it if you place it under a bright light to compensate for the missing backlight.

As i said only a small amount of liquid was spilled and it only went in centre portion of keyboard. none on screen.

So logically Im thinking either the backlight's connection to motherboard is not working or a chip that maybe controls the backlight is Shorting?

I am tech savy but have no experience with mac or laptop fixing. so inverters and lvds that ive seen mentioned mean nothing to me.

Basically could someone explain to me what could be the problem and how it can be fixed? In semi layman terms!