There are 4 T8 (or T7) Torx Screws at the bottoms of the case.

Here's Apple's technical notes on taking one apart. This applies to all the Duo's since they use the same case.

http://tim.id.au/laptops/apple/powerbook/powerbook_200_series.pdf

To replace the caps, you need to remove the logic board from the case, the area is too small to work with the logic board inside the case.

And TechKnight - the Apple Certified 50 pound Sledge Hammer is for repairing Worthless Windows PCs.  }