HT-R667 Volume Knob Issue

Hi,
I am having an issue with my volume knob on my receiver. I have been using my HT R667 on a daily basis for some time now, and now the volume knob seems to have a mind of its own. Regardless of the speed of turning, the volume will go up, down, or do nothing at all. It jumps around some times twenty points at a time, and after some fiddling trying to get it up or down, it usually settle around 11 volume. I am in a relatively hot room, but the receiver is not covered, and airflow is not blocked. The receiver is on about 8 hours a day. at around 30 volume. The remote changes the volume fine. Is there a remedy for this, or a replacement part I can buy?

I can take a video if necessary