Hi, I have an issue with my Pioneer PL-12D producing a pronounced hum. I have read threads on it, and people experiencing only one channel of hum and issues suggested to be the motor. However, with mine the hum seems to be both channels, it can go away when I fiddle with the ground wire such as remove and replace, and/or touch it to other things like the audio terminals. It goes but then it comes back, and it is there before I turn the platter motor on so cannot be feedback from motor noise. Is it likely the ground wire is simply loose inside the turntable?