Since the arrival I've had a little time to read up on Hammond tonewheel organs, and to try all of the available settings. It has a few problems, but nothing really serious. The worst is probably the non-working A-flat pedal, but even that's not so bad. The pedals cover only one octave anyway, so they're already pretty limited.
Today I opened it up to do a little maintenance. They're meant to be oiled once a year. On the inside of the back panel, somebody had noted two dates when it had been oiled -- once in 1988, and once in 1992. I don't know for sure, but this organ probably was built some time in the first half of the 1960s. I'm a little curious about the care it's had over the decades.
Some of the drawbars, which are pretty much the whole reason you'd want an old Hammond, need their contacts cleaned, including most especially the one that controls the fundamental tone for the upper manual. I'll be opening it up again in the near future to tackle that job. I'll try to remember to take some pictures of the inside -- it's really something.
We're really having a lot of fun with it. I caught Thomas making some wild sounds on it by turning it off and on while playing. I put the kibosh on that. I read that Keith Emerson used to do the same thing on his L-100, but he also stuck knives between the keys to get sustained notes and some other pretty crazy things.