Bobcat 843 battery runs down

I recently bought an early 843, and there's some kind of small electrical leak that causes the battery to run down, so I have to disconnect the battery if the machine is going to sit for more than a couple of days. I'd like to get to the root of the problem and can gradually work my way through various circuits, but i thought I would ask here whether anyone has solved a similar problem or knows of a common place where a component of insulation may tend to fail. That would let me focus my search more efficiently. Thanks for any advice.

Personally i'd start with the alternator. If you have a bad diode or if someone wired it up incorrectly it can draw power from the battery. Try removing the exciting wire from the alternator, this is switched power. See if your power drain is gone. The next thing you can check is removing the main B+ cable from the alternator, see if that works. If thats the problem, its an alternator issue. If the first one works, its not switched power from the ignition switch so it draws power all the time, not only when the key is on.
I hope that makes a little sense.