I'm at my wit's end on this one...
I left my Roomba 550 off of its home base for several weeks (I went on vacation, and forgot about it for a while before and after that), to the point where the battery would no longer accept a charge. Oops. So, I ordered a new battery. Now, the Roomba will accept and hold a charge if I plug the charger cable directly into it -- but if I try to dock the unit, it doesn't work. It goes up to the dock and does the back-and-forth motion like it's trying to make proper contact with the home base, but the base's "docked" light never illuminates and eventually it gives up. (Actually, I saw it flicker on, exactly once for less than a second, and I haven't been able to get even that far along again.)
I've cleaned the contacts on both the Roomba (which is only about 6 months old) and the home base, and I even went so far as to buy a new 500-series home base -- nothing has made any difference. It's as though the contacts on the front of the Roomba are completely "dead".
Is there anything else I can try?