I'm replying to myself! Actually this is updating the symptoms. Last night, after finally getting it to initialize (and what made it do that, I'm not sure.) I was frantically switching back and forth between the Chooser and the iDock programs and selecting what I thought were the right settings, and plugging it into various USB ports and either of the two serial ports. It still won't initialize even if the serial plug is not in the back of the printer. Unplugging it from the wall seems to help, if you leave it unplugged long enough.
Anyway, it finally came to life and I did lots of printing. I then shut the computer off for the night but did not shut off the power strip that everything is plugged into, as I usually do. This morning, the printer still works fine. Anybody know why I can't shut my printer off anymore, as I used to do? I have an old Kenwood tuner from the 70's that I can't shut off either, but I don't think that a computer printer should have to warm up. This sounds like a hardware problem, as it still does it even if I don't have the serial cable plugged in.
Val