LCD Screen Not Lighting up VERY DIM, replaced inverter still nothing.

sometimes randomly the screen lights up for a second then back off but only when it comes back from sleep mode.

What can this be? It works with external monitor just fine keyboard lights up.

I CAN SEE with a flashlight sideways everything just fine but no backlight.

The i-sight works fine, and i just replaced the inverter...

just replaced the entire screen with a working one...nothing,

also replaced the top keyboard assembly with a diff working one as well...nada

really hoping this is not the logic board...

What can i test / check to see what the issue may be?

THANKS : )