Hi
I'm not a tech in any way, but before I take this for repair, I want
to make sure it's not a simple connection/hookup issue.

I got this and a Technics turntable on Ebay, and I'm very happy with
them so far. The receiver is hooked up, radio works great, audio from
DVD/TV works great.

When I select Listen/Phono, I get a loud rumble through the speakers,
whether the TT is on or not, and whether it is plugged into the back
of the REC or not.

The noise goes up and down when the volume is turned.

The TT does work and play records, but the rumbling is underneath.

Also, the ( I assume) ground lead from the back of the TT, where does
that get connected?