Kaypro 2000 charging

[joe heck via cctalk]

Hi,
I just found a Kaypro 2000 at the local recycler.  No power supply. 
From what I can find online it has three(3) lead acid batteries.  Any 
thoughts on getting it to fire up?  I do not know the polarity of the 
power jack on the back.  Once I get that, I was thinking of a 6 volt 
supply, more to just turn it on, rather than try to charge the 
batteries.  Thanks.  Joe Heck