Discussion about the Korg PolySix synthesizer

Hi,

Im having problems to calibrate the filter section on the KLM366 board.
I followed the procedure from the servicemanual, and everything went well until:
Page 19
(3) VCF RESONANCE adjustment.

I followed instructions,
CN05-7 is at 0,02V
CN05-11 is at 8,00V.

Next the manual says:
1) Connect the oscilloscope and freqcounter with TP1
2) Play any single key and try to adjust VR6 so that the VCF waveform amplitude is 300mVp-p +/- 20mV

And here is the point I don't get it.
When I measure with my scope on TP1, the signal differs from every voice and key.
I can turn VR6, but I found out that when changing VR8, they interact with eachother.
So what is the starting situation?

Maybe I missing something completely, but I hope someone can put me in the right direction.