This site has instructions for replacing the optical drive on the powerbook. I’m thinking I’ll go out and buy a Torx T8 head for my screwdriver (it only came with a T15 and a T10 – I think there was a more expensive version of the screwdriver with the T8 supplied, but I went for the cheap version – ah hindsight!) and get the drive out and see if that gives me a better view inside.
It’ll also give me many opportunities to bust the powerbook.