Thanks for the comments. I am keeping the drive.
The noise has gone down considerably. I can still hear it, but the clicking is quieter than the system fan now.
My technical level:
This question is about a iMac G4 15" Flat-Panel 1Gb that I purchased in Feb 2002. I'm a SW Engineer by degree and trade. I have some experience with hardware and can find my way around an open computer, but don't know the nuts and bolts about firmware and chipsets. I tend to...