My K2's (#3104) RX is quiet on start-up on an intermitent basis. It's the same sound that one hears when the AGC kicks in, but it seems "stuck". To get it going, I tap AGC and it springs to life. This usually occurs when I first turn it on during the day. Subsequent on/off's during the day are without problem. Any ideas? Tnx. Gil NN4CW