My PSW202 has started crackling (sounds a bit like morse code) when the sound level goes over a certain level. If i turn up the volume on the speaker itself the noise starts at the 11am position and gets worse. If the TV sound spikes this also causes the problem. Otherwise unit seems to function normally. Recently added a Sony DTR-1010 Amp, however have had this about a month before problem started. SW is approx 6 yrs old.
Have set using all recommended settings in both manuals.

Any Ideas?