Okay I managed to resolve the issue... When I first installed the O/S epromms I had installed them in the wrong IC slots and found that the original IC's were swapped incorrectly MSB & LSB... Can't recall the IC numbers but when I swapped them around the distortion was gone... Glad I did not destroy anything... At the moment I am building a MIDIBox SEQV4 to sequence the S-1000... If anyone is into DIY this sequencer is next level stuff if you want to work OTB...
