11-02-11: Stringreen
Have you tried orienting plugs 180 degrees? If you use 3 wire plugs get a cheater from Home Depot, cut/saw off the grounding plug and try turning (one at a time) the plugs of the stereo. If you come across the culprit, change the wires going into the plug behind the wall and get rid of the just bought "cheater".
No, do not do any of these things, most especially the last suggestion, which would create a serious electrocution risk if a component in which ac neutral and chassis were connected together is ever plugged into that outlet. Some vintage components were designed that way. With any component that condition could arise due to an internal insulation fault, a wiring error, or a part failure.
And reversing the hot and neutral inputs to any component, either with a cheater or within the outlet, will cause the component's power switch and main fuse or breaker to act on the ac neutral ac wire, rather than on the ac hot wire, which could cause possible internal fault conditions to result in a fire hazard, a shock hazard, and a hazard to the component.
Regards,
-- Al