Every once in a while, booting from the floppy with the hard drive connected, it did get past the "Just a moment..." message and finally finish loading the OS from floppy, though it took a long time. Sadly I still get the "HD Catalog Error" whenever I attempt do do anything that requires the hard disk. But it is an interesting change in behavior. It's a small clue, though I don't know what to make of it yet.
Jim