Emil.D

Hi there, I have had this RSW-12 along with RF-7's and an RC-7 for years now with no issues and today as I was attempting to adjust the volume control knob on the RSW-12 I found it to be unresponsive. For nearly all directions it plays one constant volume and at the 1'oclock setting it just cuts out, silence. Has anyone else ever had this issue and if so how would I go about fixing it. Thanks, Emil