Has anybody ever seen this before?
My hi-fi system is about 9 years old. The CD player section died about 6 years ago but the amplifier still works fine.
The volume knob is digital and doesn't have a "start" and "end" position - it can just turn indefinitely. Recently I've noticed that it has become slightly erratic. I will turn it up just a couple of notches (say to a volume of 10) and go away to empty the dishwasher; come back to it five minutes later and it's crept up to maximum volume. It happens the other way; it will gradually work its way down to zero.
Maybe it's a sign to finally replace it with something a bit more modern (Dolby Digital and DTS versus Dolby Pro-Logic) but in terms of sound output it still works great and I'd like to fix this problem if possible. I can't use the remote control because the remote sensor is unbelievably useless on this model, even with my Logitech Harmony remote blasting out a high IR beam.
It's probably caused by carbon buildup across the switch contact area.
If you are able to take it apart, you can try cleaning it with WD-40 as you vigorously turn the knob back and forth. If you are unable to do that, then vigorously work the knob back and forth anyway for as long as you can tolerate doing it. That will clean off some of the carbon and should resolve the problem - at least temporarily.
I learned to use WD-40 as a communications officer in the Army. It worked great and has never caused a problem for me.
However, JA is right - it is petroleum based. So a specialized product is probably best.