David Shanahan offered some important tips for avoiding trouble with iBooks.
I recently had the video die on my 800 MHz G3 iBook for the first time when it was almost out of warranty. It was fixed, though apparently because of the high demand for iBook logic boards it took three weeks to get it back. So far it's working fine but based on others' experience this is unlikely to last.
I started reading the Apple support forums on the subject of video failures in iBooks while I was waiting for mine to be repaired. It seems there are two basic flaws in the white (Dual USB) iBooks (both 12' and 14' models) which Apple seem to be studiously ignoring despite complaints about them being widespread for over a year now:
1. The hinge design is faulty. Backlight, video and power cables pass through the hinge from the logic board to the screen and the holes are too small for the cable assemblies resulting in stress and friction on the cables each time the screen is opened or closed. Eventually one or more of the cables either break or the insulation wears through resulting in a short and the backlight/video fails. This is often accompanied by fuzzy lines on the screen or users finding that the screen fails when tilted at certain angles and works at others. If your video works fine when you plug the iBook into an external monitor then this is most likely your problem. There are links in the Apple support forums to a site describing in detail how to disassemble your iBook and replace such broken cables, though you'd want to be pretty confident to try this as it will of couse void any warrenty you have left.
2. The video chip on the motherboard comes loose when its solder gives way leading to video failures, usually with no warning. This may be triggered by flexing of the case putting strain on the chip until it eventually comes loose (some have suggested never picking up your iBook by the left-hand side alone as this is where the video chip is). If after a video failure you plug in an external monitor and it doesn't work this is most likely your problem and you need a new logic board. Some people have tried pressing down hard on the left-hand side of the case just below the option key to the left of the track pad and managed to get video back temporarily (apparently this reseats the video chip). Others have reported some success sticking rubber bands/thin foam insulation on the underside of the shielding over the video chip to protect it from flexing/pressure from the case. Seems like the case really needs to be reinforced to stop it flexing like this and/or the location and soldering of the video chip changed.
These problems appear to be common with every model of white iBook from the original 500 MHz up to at least the 900 MHz G3s. The new G4 iBooks may have the same problem(s) but they're so new it's probably too soon to tell for sure (the hinge design has apparently not changed). [...]
P.S. I'd advise readers to avoid buying 2nd hand white iBooks - many people seem to be selling theirs after the 2nd/3rd/4th logic board replacement and buying something else (not always another Apple product of couse, which has got to hurt Apple if they continue to ignore these problems).
1. Open and close an iBook as infrequently as possible, move it with both hands. In short, treat it like it's made of glass.
2. Apple should admit the problem and provide an out-of-warrantee solution.
3. Apple is not completely censoring these discussions on the Apple support forums.