Macbook pro silver key SCREEN DIM

Hi guys

I have a 15" 2.4/2/200 silver key macbook pro. The clutch had broke and the screen was dim . Classic backlight symptoms. So I swapped out the whole dsiplay assembly (not just the LCD, but the whole thing - clutch, metal casing, all the cables, etc.) with an extra I had tested. I figured it was the inverter and it would be a simple fix.

Screen is still dim even with all the new assembly installed. So...I tested the original dim screen display assembly on another machine and it worked fine.

So I concluded that this is not a problem with the screen or any of its cables or boards.

So, what faulty part would cause the screen to be dim that is NOT located in the screen casing?

I do get an image with an external monitor.

Thanks

try this. remove all power from the computer and then press and hold on the power button for 10sec, when you do this nothing will happen on the computer. put power back and press and hold "option, command, R, P" and turn the computer on. keep them held down until you hear the second chime and when you hear that you can let go.

a funny follow up.

took the comp into apple for service. they put in 2 different logic boards and still had the same problem. still waiting for a prognosis and solution. its been almost 2 weeks. ill keep y'all posted...