Check that. That is what I did. I read and re read the manual then I adjusted both the pots on both channels for DC offset and re checked it again to make sure I did not miss anything. Everything checks fine as far as DC offset. The Bias is what I am haveing trouble with. The left channel Bias will not adjust any higher than .140 mV. The right channel Bias adjusts easily to the correct adjustment of between .300 -.400.