So Yamaha CR-800 I had it with dead left channel. Problem on the main amp board. I reflowed all soldering on the left half, and boom, I had the left channel back and clear. So I put it all together. Checked bias/middle point as they call it in the manual. For the left channel it was oscillating between - 30/+30mV, very unstable. Suddenly it was all over - 300/+300mV with OL open circuit now and then. It stayed like that. I have heavy crackle in the left channel now. The other channel is all ok. The relay clicks ok. Idle currents set ok. Any ideas?