I am attempting to repair a drive problem in a Powerbook G4 aluminum 15-inch dual-layer SD (superdrive) computer. This is the one with a giant spring-loaded screw on the back to release the battery. On older models like the pismo, the keyboard lifts up easily, and the drive is right under it.
With this model, the hard drive is in the front of the machine and is accessed by removing the whole upper case including the keyboard. This is even worse than the similar operation on a powerbook titanium.
This was assembled by a truly evil mind! To open it, you need to remove tiny screws on the back (about 6), 4 on each side, two small hex screws on on the top near the display, 2 scrws inside the battery compartment, 2 screws inside the memory compartment. (To get the small hex screws out, I had to insert two extra-small slot heads at once to apply enough tension to rotate the screws.)
This is a huge pain and does not seem to be documented elsewhere. All together I count 23 screws, but I might be missing one. After that, to remove the drive you need to remove 3 screws on the tension bar on the right on the drive. They do a low of wiggling and prying.