To replace the floppy just pick up an external
floppy drive and pull it out of the case. It should
bolt right in. I had a C=A1200 (sold it), with a bad
floppy, I had an external floppy I used with my A500,
(sold that one too), anyway I just pulled it out of its
case and installed it internally in the A1200.
It worked fine, the only problem is the eject button
usually doesn't stick out as far as a regular internal
drive, but other than that, no problems.