Hi Tim,

It definitely sounds like the cable could be faulty.

You can use any co-axial cable to link between the Master speaker's output and the Slave speaker's input to prove this.

It is quite easy for the connections to break inside the phono plugs, or it could be oxidisation on the plug contacts...

Good luck in resolving the issue.

Cheers,

Steve

Main: 861v6 (LPS), 808v6, UHD722, DSP8000SE Anniversaries, DSP5200HC, DSP7200.2, SW1600, Sky Q, Cambridge Audio BD, Roon, M80
Office: 861v4 (LPS), 818v3, 800v4, HD621, M&K S150P, DSP5500HC, M&K MPS2810 sub x2
Son's system: 861v4, HD621, DSP6000.2, DSP5k.2C, DSP33, F80
Spare: MCD, 100 Series, 200 Series, 500 Series, C15s.