grounding issue

I have isolated the noise problem to the tonearm/cable.
Grace 940
Cardas Golden Ref. phone cable
Noise is present without headshell/cartridge attached.
How do I isolate the problem??
What am I missing?
I think you need to attach the headshell and connect the cart...if the noise is issue. maybe i missed something from your post??
Hi and thanks for the replies. Since my post I have learned a couple of things. First is about grounding plugs to test a particular component. You insert grounding plugs in place of the interconnects to complete the circuit and this allows you to test an individual component for noise. So with regard to the headshell you are correct, it needs to be in the circuit, if you ground each channel of the headshell, in other words a lead between the plus and minus you can test for noise. In my case I needed a ground from the tt itself to the grounding lug on the preamp.
Again thanks for the replies.
Hi, that makes sense...something in the circuit...