I have had this amp for Approx. 6 months, and was working great up until a couple weeks ago. The amp is setup with a custom preset, input Y, Bridge Out, Xover and EQ settings. It is driving a 4 ohm load. When I power up the equipment, the amp will not play anything, even in Sys Arc under the input tab is a test button and it will not work either. I can get it to work if I press the mute button, wait, then unmute, it will work for a while but then go back into a muted state, even though the preset is saved as unmuted. I have updated the firmware, and this did not resolve the problem either. Any suggestions. Thanks.