T21 dark screen, backlight power, bad system board?

[skygodtj]

Hi all!

A friend of mine brought by his T21 for me to dig into. The problem began with the display blanking(going dark) uncommanded. At first I thot it was the suspend switch, but doesnt have those symptoms, it doesnt sleep... On power-up, I can see the screen barely come on, change intensity, the IBM logo appears but is very dark, just as if the backlight was bad, then the LCD screen goes completely dark and XP continues to load. It displays fine on an ext. monitor. I swapped the LCD and inverter with ones from a working T20 but the problem persists. At this point I'm suspecting the system board. Anyone have any other ideas?

Thanks,

TJ