I would tend to agree with both of the above replies. However, the turntable is grounded to the receiver. Continuity of that ground between their respective chassis is confirmed. And true, there aren’t any electronics between the cartridge and the patch cord. This is an American market unit and not equipped with the typical DIN plug; it is equipped with RCA cables which have been replaced.
At idle, there is no hum. However once the motor is running, the hum is present . Low level, but present and it shouldn’t be.
The service manual found on the internet does not address the 2400 (5716) model in particular. The parts lists and even component locations on the PC board don’t match.
I suspect I have a ground loop within the turntable or an issue in the power supply. It’s been in my hands since new and has never been in a shop. I’ll report what I find as it may be useful to others with this model in general.
