I have a mid-90s Washburn MG-40 electric guitar. It was very crackly when I acquired it so I took it to be serviced.
I'm new to playing electric so the tone knob is a bit of a mystery to me, but mine is surely a bit odd - it's effectively only got two settings. Turned all the way down, I get a very muted "underwater" sound. Turn it a little and suddenly it goes to a "normal" sound. That's about 10% of the travel of the knob - the remaining almost full turn makes no discernable difference to the sound.
I assume this is a problem rather than a feature but I'm not sure quite what it means or what to do. It seems an odd fault for a potentiometer to develop to me!