Hi Joe, > The 600Mhz definitely has a fan. You're definitely right. I looked closer to a picture I took when I disassembled the 600MHz iBook, and I discovered that fan (which never, ever spinned). I put that picture here: http://homepage.mac.com/robegian/PhotoAlbum13.html (The photograph is in the bottom of the page - the one with the green arrow) Roberto Giannotta Trieste, Italy