For no apparent reason, our PS3 (80gb version) is not producing any audio.

We played a Blu Ray movie Friday night and it worked perfectly. Tried to play a different movie last night, and we get video, but no audio :(

It is not the disc, as we have tried several Blu Ray discs that we know work (including a game disc) and we do not get audio with any of them. We just upgraded our firmware, but all discs had been playing flawlessly prior to last night.

Connection is a PS3 HDMI cable to a Pioneer Elite Reciver VSX-81TXV, running to a 50 inch Pioneer PDP-5071HD Plasma.

Any advice would be greatly appreciated - thanks in advance!

Try re-engaging the PS3's autodetect function. Turn the console off. When you turn it back on hold down the power button (on the console) until you hear a second beep.

If that doesn't work, double-check the PS3's audio settings against what you know about your home setup. Also double-check your AVR's settings for that connection.