I've had this receiver for some time and for some reason it continuously mutes itself. I will be watching a program and suddenly it will lose all sound w/o warning and w/o any input on my part. Just no sound. The only way to fix it is to power off the JVC RX-D401 wait a few moments and then power it back on and it seems to work every time. I use a SonicView 8000 HD FTA tuner and while these aren't the most stable boxes out there they are more stable than the Comcast Motorola tuners we used to use. Of note I have this same FTA receiver in two other rooms and this is the ONLY A/V reciever that has this problem so that's why I'm leaning towards it being the problem of the receiver and not the tuner. I'm running the tuner to it via HDMI cable and then from the receiver to the plasma via HDMI as well. It seems as though I can provoke it by turning the volume down (the volume is set static on the receiver and the tuner is what controls the volume) to fairly quiet because I seem to notice it more when I'm on the phone or something. If this was the only time it happened I would say that it's possible going into sleep mode due to lower output of the tuner but the fact that it happens at any volume is frustrating and confusing.