Starting with all pots at Center position, I do get 0V on the data pin.
All pots to Min: I get -4.35V
All pots to Max, I get 4.35V.
Since Res is the only pot which works the other way round, I get this is ok?
Avg sweep for the Cutoff pot, I get a variation from -4.35V to -3.73V...
I was using the Res line on KLM-367 as it seems it is the easiest one to verify, but I agree, I should focus where the issue seems to be and if it's the DAC, investigate there. Also agree with the need for a scope...
Yash