OK Good idea, I have put a ticket in and some repair man is presumably going to give me a call: In the meantime, I have disconnected the device and suddenly note that it isnt absolutely passive in operation and that there is a switch on it with the two options on it being either SAS or ADV. It has always been set to ADV.

DO you have any idea what these settings refer to please and is this some reference to control voltages by any chance?