Thorens TD-165

Recently purchased this rebuilt Thorens TD-165 from Germany. Turntable is 240VAC and a step-up transformer was included in package. Found 60HZ hum from right channel RCA connection that I can control the volume with my McIntosh C32 preamp. The ways I can get the hum to quit...pull right channel RCA lead from table; disconnect the 240VAC lead at the table coming from the transformer or unplug the transformer from the 120VAC wall outlet. The hum is present even when I turn the transformer off with it's power switch, but leave it connected to the table. Sales in Germany is on vacation until next week. Will talk to them at that time. Any ideas to a very old problem?
Check your cartridge connections.
Make sure the tonearm/TT is grounded to the preamp.
Agree check cartridge tags. Check table ground wire-spade connection, that wire is usually thin and fragile and sometimes many strands are broken off unnoticed, solder it if can. Table may have ground wire off tonearm bolted to chassis with another wire bolted to it running to ground spade, that bolt connection can be loose or bad. Put it on some books and look under there. I had a linn do that it was chassis ground bolt, check ground to din plug. Good luckĀ