Screen suddenly VERY dim

[ridingonchrome]

In June I brought my G4 in to replace the DC-in board and once that was replaced the computer would only boot in safemode. Specialist stated I needed a new logic board. I didn't have 900$ at the time so I left it. I recently purchased a logic board and took my old one out to find that it was not compatible. So now I am in the process of putting the original one back in. Everything is connected but not screwed down and the top is still of. When turned on the screen is VERY dim, I can barely make out a box but have no idea what it says. Good news is it looks like its not in safe mode as I didn't have to enter a password (as far as i can see). So can someone help as to why my screen is now suddenly VERY dull (was perfect before) and why my keyboard isn't working?

Any suggestions would be great, and No i am not with apple care anymore.

[Eraserhead]

You've probably blown the backlight, that makes the screen. very very dim (almost unreadable), see the attached photo, for what my Macbook looks like with the backlight off.
60205

[ridingonchrome]

You've probably blown the backlight, that makes the screen. very very dim (almost unreadable), see the attached photo, for what my Macbook looks like with the backlight off.
60205

thanks, how do I go about fixing it?

[Eraserhead]

thanks, how do I go about fixing it?
first check the connections you may not have plugged a wire back in correctly.

[Hockeypuck]

Sounds like your inverter board is not working correctly. It would be one of the cables that comes out of the display hinges and plugs back into the logic board.