My bookshelf speakers have hum that comes and goes with a decrease in volume at the same time. I opened them up to have a look and there is an obviously burnt resister. Tracing out the components to a diagram and matching it to a diagram from the op amp spec sheet. It has the resister and capacitor labelled as being for frequency stability which maybe would cause a hum?
The questions are: why did they burn out (it's both left and right sides) and are they the only broken parts?