A friend has inherited a Nuvo Essentia nv-e6dm and I've helped and added some stuff in particular a Sonos. I am controlling the Nuvo with iRule via serial. Now I can get it to switch on via iRule and to switch zones on / off ( zone related lights and clicks heard ) but there is no sound coming from the amp and I cannot positively tell if volume etc is responding. I assume if the iRule commands are correct for power, zone etc they are for volume etc. I know the Sonos is outputting. May I add it was left running via iRule about 3 years ago with no changes since so I'd thinking a delve into Nuvo configurator shouldn't be needed ??
Is there a factory reset or any way of checking if the amp is working / responding ?

Thank U