Sherwood Newcastle P965 PreAmp Processor - No Audio Problem

I am having a problem with my P965 . After turning the unit off it normally goes into standby mode and a blue lite shines on the face of the unit. Now when I turn it off the lite turns yellow . When i turn the unit on it goes to the correct source and the lite turns back to blue but I get no audio. In order to get audio I have to manually hit the decoding button till I see AUTO on the display - then I get sound. Does anyone have any idea what is causing this and how I can correct it ?
TIA
Bob