Thanks for the responses! That is a lot of interesting information.

Tom - I'll try to get a good picture of the knob and post it. I'm going to take a look at the info you have on the receiver. I just need to download a plug-in to view it.

Jeff - I am really glad that you pointed that out. I just looked at the wire that you were talking about and it seems that it must have gotten so hot that the wire melted to the tube! I guess I'll just leave it unplugged for the time being and look into replacing the tube if possible, because if I try to force them apart, I'm pretty sure that the tube will break.