Thanks Aaron! What you say makes a lot of sense and seems like it applies to my problem. Could you post or email me a source for the transformers. I've got enough charger bases that I would be willing to try the xfrmr fix. As far as the resistor I can barely see the little board in the charger base let alone try to desoldier and reinstall a resistor.
Since my original post I have purchased a B&D Multi-Voltage 1 Hour Charger (model PS1MVC). It is working fine and has even reconditioned some of my older batteries that were not holding a charge as long as they once did. This charger seems to have all the features that safeguard the charger against completely discharged batteries. Plus it has a maintenance feature that allows you to leave the battery in the charger indefinately. Even has a feature to alert you to a bad battery, but I'm not convinced on that one because it is showing all of my batteries to still be in good shape.
Wish I would have bought one years ago when I first started having problems with the PS-180 model.
Almost forgot....bought it for $25.99 at reliablepowertools.com. And I don't work for them, I just like their speedy shipping and low prices.