DELL LAPTOP WILL NOT CHARGE BATTERY

DELL LAPTOP - INSPIRON 6000 - NO CHARGE. I have been an Electronic Technician for 30 years, but have never got very deep into repairing computers beside assembly changing and re-configuring. I have the laptop mentioned. It was given to me. I have tried several batteries and none of them charge. I tried three different Dell power supplies and the bios setup does recognize all three different power supplies by their wattage. I tried 65 watt, 90 watt and 180 watt supplies. The bios setup screen shows the batteries at 5-10% charged. I did notice that the power supply jack was loose. I had to remove the motherboard to get to it, but was able to see FOUR solder joints that were wiggling in the hole. I resoldered the loose connections. After reassembly, to my surprise, nothing had changed. Please note that until parts arrive this laptop has NO hard disk drive in it. I do not think the HD is needed to charge the battery. I am under the impression that battery level and charging is handled exclusively by the motherboard and firmware and does not care about an HD. Is this correct? Other than replacing the motherboard which I would not do, is there anything I might check to restore charging capability of this laptop? There is every possibility that I am missing something that would be obvious to someone that repairs laptops daily.