How to ground old turntable with no grounding wire


I have an old Marantz turntable that I want to start using again. I have a terrible hum through my speakers when it is turned on--worse when the tone arm is on its rest, better when it's over or on a record. I'm guessing it needs to be grounded (although it was never grounded when I used it years ago). But, it has no grounding screw or wire that I can locate. Suggestions? Any ideas for other causes of this new hum? The other thing I'm wondering about is electrical polarity, because it has an old (non-polarized) plug, plugged into a polarized extension cord. Any and all suggestions welcome!
flowergarden129

Showing 1 response by andy76

I have a similar issue only i made it worse. My wife gifted me a  turntable with shelf(non powered) speakers combo from amazon. The TT has 3.5mm L + R connections in the back. The speakers that came with the TT sound awful. So i decided to plug a pair of yamaha hs50m (powered monitors) to it. As soon as I connect the TT powersupply i get the hum even if the TT is off. However if the plate starts spinning the hum goes away.

So i started googling and visiting boards in which the consensus seemed to be that TT needed ground conection. Sooooo I soldered a wire to the ground labeled spot on the pcb. Grounded the TT to the powerline ground and the hum went away. I felt triumphant until the plate started spinning.... now i get a clicking sound (about 1.5 clicks per second). As part of the trobleshooting i connected the non-powered speakers back to TT, no hum,no clicks.

If i connect 1 powered and one non-powered speaker to TT without turning the yamaha speaker on I get the click through the non-powered speaker until i disconnect the power cable from yamaha.

Anyone has any insights or ideas as to what the issue may be?