On Sun, 2 May 2004 23:09:40 +0100, "Craig Graham"
wrote:

There has to be a ground. The only reason you're getting anything at all is
because it's finding a very poor return path somewhere.

You say power is live/neutral. Are you sure it's not DC? If it's DC, then
one of those supply wires will be the ground and you have to bring that out
to both the audio and video shells. If you get horrible hum, just do it to
either audio or video but not both. Alternatively, is that audio wire really
audio or could it be video ground? Do you definitely have audio on those
cameras?

Yes it's DC power - so can/should I take the ground from the power
supply and connect it to the grounds on the video and audio phono
plugs?