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When you say "nothing works".........are those all 12 VDC powered systems? Do you have a small digital multimeter for some testing or a 12 vDC test light? That makes this a whole lot easier.
Make and model of your load center would be helpful here. Most of that vintage would be made by Magnetek.
Just checking back in to see if you were able to resolve this issue or do you still need some additional input from me here?