Hi to everyone - nice to be part of this group. Haven't had a chance to participate much in this area since I stopped organising the Hampshire Jam events in the UK, as I've moved to Malaysia where I live and work nowadays - and Malaysia isn't a hotbed of analogue synth aficionados.  

I've had my Doepfer system since 2000 and am still amazed at how each time I start patching time seems to stand still (or so my wife says!).

I'm not especially technical, so please bear with any schoolboy errors in terminology.

Anyway - question re: VCO calibration and tuning.    

I have 4x A-110 VCOs and all  of them over the past 14 years have drifted away from their factory-pristine state.  Having read the service notes, I decided to tackle the immediate issues I have with the range switches 1  and main tuning [P1].  

1. I set 1 to 0= middle, and 1 to 5 =middle to start with.   I then checked the range of 1 by turning +/- 2 octaves and tried to calibrate with [P5] - the range potentiometer.  Whilst the tracking was a little off +/- 1 octave from 0 (ie 20-40 cents), by +-2 octaves the offset had increased to over 100 cents.  How can I adjust [P5] so that the range steps are equal...  I didn't seem to find any setting that gave even close to a 1 octave per switch movement.

2. Dumbass question, but should the VCOs be producing C with 1 at 0  = fully anticlockwise, or at 5=middle position   My 4 VCO's all seem to tune closer to A at 1 = 5 = middle position.

Appreciate any advice or education on this.

Thanks,

Steve Jenkins