mr mike look at joining the trustedtradesmen forum it sounds like you might know your stuff and you'll be welcome
The batteries are a mixture of ni cad and ni mh, the charger does charge both, i have a other charger that only does ni cad and it seems to charge the ni cad up, but the duel charger will not chare either, it lights up to green to say the battery is charged but they are not, can not find any internal fuse and the main fuse is fine.