Korg MS-50 Diode Bridge VCF Calibration

[Mike I.]

Anyone know the calibration procedure for this? I recently built one 
from the schematic at the hyperreal site (using the CA3019 array). My 
system uses +/- 12 volts, I think the MS-50 uses +/- 15 volts and is 
scaled at 2 volts/octave. I am using VR8 for initial freq trim, and am 
adjusting VR9 for minimum CV feedthrough. How does one adjust the 
unlabelled 33K trimmer connected to D28 (temp compensation?). Is this 
VCF actually capable of accurate keyboard tracking? (I assume the 
"Cutoff Freq" input jack connected to VR12 would be required for this). 
Any help here is greatly appreciated!