[chris vickery]

Stewart, was just having this very same discussion with a friend of mine who is an auto electric wizz by trade. A real pro in the word of rebuilding all types of gens, alternators etc.
He said that a junk battery is the single most common problem with electrical systems and often makes other components look faulty. The number of people that get taken all the time for new alternators, starters etc is amazing, when all you need is a battery.
I just proved this to myself last week with bad battery terminals which made my alternator act up because it didn't know what to do. Lucky I started at the most sensible place- the battery.
Can't recall which wire you leave off the regulator to polarize it, but it is something like the "field" that you leave off and touch momentarily to establish polarity. A new reg should advise of the steps in the instructions, if any.
Good luck