same problem my amp shorted out then it shorted out my mute button which after awhile it will not come on at all.everything will work fine just no sound.replace your amp.this is what happen to mine had that happen on my rx300 what caused it to to go out was the mute button shorted out it had that feature for the phone but i never used it so it thought i was on the phone in turn it shut my radio off but everything else still worked.so instead of sending it out for 6weeks to cali i put a new amp and a eq with volume control to solve that problem and it only cost me 250 instead of the 2000 they was talking about to find the problem and replace the radio