AV receiver pioneer is SC-LX86 which I had from new since 2012 with no problems until now. I notice watching movies via BD player after maybe 15min if i pause or stop play rewind or forward there is a terrible high pitch noise coming from the back channel speakers and no sound from any of the other channels. My AV receiver setup as 7.1 were I bi-amp the front speakers and using normal side and back speaker channels. If i turned the receiver off and then turn it back on the noise is still there and after maybe 30sec everything goes back to normal sound wise. I thought is was the BD player causing the issue but notice its doing the same when am using the Play Station or Sky Q box. Even when am streaming music and i switch source the noise will kick in and then i've to turn the receiver of and on again. Very frustrating as i love the receiver.