Yamaha CS80

Hi. Thanks for your reply. On your advice I did replace the caps on the S/H board which got rid of some unwanted crackling. Then went back and re-calibrated the power supply, S/H and KAS boards. Which I had already done, but the tolerances are small and some were out. Also the transposition gate zeroing on each voice shifted a bit (0mv between cp6 and EK). The tuning was then better, but still three or four voices were 20 or 30 cents flat on the lower octaves on the 8 and 16 feet ranges. Eventually I tried swapping the VCO chips around and found the fault moved with the VCOs. So I think I cannot improve it any more.