Glad the OP solved the problem. I ditched my analog outfit years ago but before I did I had a hum that resisted multiple approaches to eliminate until I bought a "hum buster" or some such thing that apparently isolated the hum and turned it into light.
As a confirmed digital lover I have to say there was a. real entertainment value to reading some of the posts in this thread. I particularly liked the suggestion about putting silly putty on an expensive tonearm/cart configuration