Hi, I'm thrilled to report that I just bought a Hammond L-100 for nothing on craigslist. I love Hammonds; unfortunately, I don't know much about how to care for them. I tried the organ yesterday and I'm pretty sure everything worked--it sounded pretty good. No grinding or weird noises. Drawbars seemed to have worked as far as I could tell. The pedals might be questionable. It has had one owner who bought it in this area in 1966, who it seems might have been a church organist from the books I also acquired in the purchase. Cabinet is in excellent shape, but it needs a good cleaning.

I've read about "oiling" the tonewheels and about an "oil cup" can anyone help me with this? I'm actually moving the organ over tomorrow. I think I can purchase Hammond Oil online, but I can't find anything that points out where the cups are, how much to put in, how it "gets oiled" (like a car--just by running the motor? or do I have to oil each wheel?).

Any advice on other things I should look to fix or how to clean it would be very much appreciated.

You will find oiling instructions with pictures at this link:
http://www.bentonelectronics.com/serviceinfo.html

Do not over oil the unit, it should be oiled yearly. You might SLIGHTLY over oil the first time, if there is evidence that it has not been oiled recently. The oil will drain from the cups, there is wicking through the generator that gradually distributes the oil so that each bearing receives some.

If it is otherwise working, there is not much other maintenance to be done. Resistors do go bad with age, same with tubes; but you will probably need a tech for that type repair. You can safely oil the instrument yourself. Do not touch the electrical connections, 110vac for the motor is on some of the terminals - they usually have a cover over those, but someone might have removed the cover at some time in the past.

No harm in adding oil. But you'll know if you over-oil it because it will drain onto the floor. Hammonds are way over-engineered. You probably won't use it a lot, and won't need to bother with oil. I play a 56 B3 at a nightclub, and honestly, that thing has probably not been oiled in 40 years. It still starts and runs.