MacBook Pro LED - no backlight

I have 15" MacBook Pro model A1226. This model has LED screen and the problem I have is that there is no backlight. I have searched the forum but most of the posts refer to an inverter which my model does not have as it has a LED screen. I can connect the laptop thru DVI cable to an external monitor and I can see the screen. There is also a faint image of the desktop which would indicate that just the backlight is out.

Any ideas what should I be looking for? I have figured that I will ask this question before I took the laptop apart.

Thanks.