A friend brought me her 12" 1.33 GHz G4 iBook. It had been working fine. Then it died. When you press the power button the fan goes on after a few seconds but the screen remains black. I reset everything, but no change. Is this a shot logic board or video card (if there is one separate from the logic board)?

Also, I have a 12" 1.2 GHz G4 iBook that I am no longer using. It works but the screen has a bluish cast to it. What could the problem be with it? Again- logic board or video card (again, if there is one) or LCD? Is i possible to replace the logic board from a 1.33GHz with the one from a 1.2 GHz?

The first one definitely sounds like the logic board. The video is just a chip on the same board.

Bluish tint can be caused by a few things. First is software. You may want to check your video calibration settings or you may want to create a new user account and see if its still bluish on that account with all fresh settings.

After that, it it probably either the LCD or most likely the display cable. If it gets better or worse depending on the angle of the screen that points towards the cable.

Otherwise it is the logic board. I'll probably take it somewhere to be diagnosed on the 2nd one. Probably too expensive sending parts back and forth just to test.