hi Steve,
by way of an update I unscrewed the coax phono that goes into the slave and found that the central wire had come adrift !
I got the soldering iron out and made a new connection and its all working fine now.
I cannot begin to explain the relief !
In addition to the DSP6000's I have a MC200 and a Digital Sound Processor. I am 66 years young and it's the best system I have ever been so lucky to own.
Best
Tim