I'll leave this to JP or someone else with more expertise, but I have to wonder whether using a power conditioner and not per se a step-down transformer could have anything to do with causing the hum that you perceive. Obviously, yours is a standard 100V unit.
In the longer term, you would want to replace ALL the other electrolytics, as well as those on the Power Supply board.
In the longer term, you would want to replace ALL the other electrolytics, as well as those on the Power Supply board.