I have now had my 3rd receiver fail in the same way, in the same installation. Symptoms are no audio whatsoever (no output from speakers, headphone plug or RCA outputs), but software apparently working OK except with spotty network connectivity. This is in a location where speaker cables might occasionally short - is there a separate internal fuse for just the audio section that could have blown?

Actually, seems it is some strange software bug - an interaction between squeezecenter and slimrio. A full reboot/reload of both squeezecenter and the rios got them working again.