Chosen Solution
I just took it apart to remove a loose screw in the optical drive and now the screen is dim…did I disconnect something? I am also having trouble getting the keys back on (is it a coincidence that one of the keys I removed was the dimmer key and the other is the brightener key)
You may go to the system preferences display preferences and check if you can modify the brightness from there. If yes then the keyboard has a problem. Try with an external USB keyboard.
try turning up the brightness, also charge your battery, the screen dims when the battery lowers, you could try to check the display cable too.
What is the PowerBook model (speed) ? 12"/15"/17" ?
You still have video in the screen so the new display cable will not solve the problem. From your description it seems to be a lightning problem related to the inverter cable, inverter board or backlight. You say the screen is dim. Is it completely black or there’s still light in it ?
If the long screw you are referring to pinches a cable it can cause problems. only YOU can tell if you put it together properly - why not take it apart and check - that way you also can check if you damaged a wire by routing it incorrectly.
