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?