Try checking the circuit at the breaker for any indications of overheating or loose connections. That will be easy to do. A loose connection on the circuit or its ground could be causing the problem. Turn the breaker off and check all of the receptacles fed by it for tight connections and good grounds. Pop the breaker out and replace it with the same style and amperage rating. The breakers are only like $6 at HD or Lowes and take 10 minutes to swap out.
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Music system
Model 990/7500/Magnepan 1.6 QRs/Technics SL1200 MK2/Aperion S-12 Subwoofer/OWA3/Sony NS75H DVD
APC H15 Power Conditioner

TV System
Large Advent Loudspeakers/ Polk center/Monoprice surrounds/Panasonic Viera 42 inch/Onkyo HT-RC260/Sony BDP S590/Directv


Home Theater System
Onkyo PR-SC886/Outlaw 7125 Klipsch RF-82 L/R,RC-62 center, RB-35 SR/SL, BENQ HT1075, Outlaw LFM1-EX/OPPO BDP-83/Directv
Harmony ONE
Blue Jeans and Monoprice interconnects
APC H15 Power Conditioner