Mark:
I was in a rush and for that voltage backward, apologies. I deleted that message and corrected my error below. Thanks for calling me out on that, the manual voltages are correct.
When calibrating, the Brilliance lever should be centered and the Resonance should be at maximum (pulled fully toward you). All related sliders (filter types, initial level etc) should be at 0 or fully low.
When setting up the HPF, the two LFP sliders next to it on the panel (cutoff and resonance) should be fully up. Conversley, when setting up the LPF, the two HPF sliders next to it should be fully down. When setting up either filter, resonance for that filter should be fully up.?
For HPF, the voltage at the FH terminal on the R6 board should be +4.0 VDC . Once you set this exactly , measure the voltage at the wiper terminal on the filter slider. You can now use the wiper voltage to measure when setting up each voice. Mine is 4.625 VDC at the wiper when 4.0 on the R6 board. Do the same thing for the 3.3 VDC setting at the FL terminal for the low pass filter slider. My LPF wiper measures 3.925 VDC.
For the HPF, I set up max amplitude at 7.6 V p-p per the CS-50 setup sheet, not 4.3 VDC as on the CS-80 setup sheet which I believe is incorrect. The 4.3 setting just doesn't give you enough resonance. There's a blog on the web that says 8.4 V p-p is correct, but I found that too high. 7.6 is nice, 4.3 is anemic. Read the signal using the oscilloscope at the CP7 terminal on the M card for HPF and at the CP8 terminal for the LPF.
It is very important to make sure the wiper voltage is set exactly when adjusting each voice. If your pot is dirty and jumps around, even a little, take the time to tear it down and clean it. You will never have a CS-80 with even sounding resonance between voices if you don't have the wiper voltage the same exactly for each one, shoot for ± 0.020 VDC.
