polarity for a Compaq armada 100s notebook

Hi,

I am trying to set up a old notebook(Compaq armada 100s) for navigation aid, one thing that I've not found in the manual is which way the polarity is, (outer negative and center positive or is it the other way around?), for the 12v battery eliminator, I've serached HP's site for info on this, haven't found any info, anyone know how the polarity is for this old notebook,

thanks in advance

K.