I have a 2003 C230K with Basic MB stereo not H/K. A month ago the volume would drop from say 40db to 20db and jump back up to 40db continuesly. To remedy, I crank up the volume to stop it from jumping around intermittently. The volume is turned up but the sound is not as loud nor as clear as it used to be. This happens to all the speakers including the amplified enclosure so I believe it to be the receiver. Is it software/hardware/lose connection? Any ideas or thoughts would be appreciated.