> one of my A-111-1 that I bought used exhibits a defect such that
> when the position of the PWM control is advanced clockwise beyond
> halfway, the VCO pitch increases about an octave- instead of the
> rectangular output appropriately transitioning through the
> remaining duty cycles down to zero. I have three other fully
> functional A-111-1 on the same bus which of course do not behave
> this way. If because of PCB mounting an improperly connected VR
> terminal is unlikely, would there be an active component
> responsible for this error Thanks!

I suppose that the CEM3340 causes the problem. You may swap a CEM3340
temporarily from one of the other A-111-1 to find out if that's true. The
scale will be not correct after the swapping but to find out if the PW
affects the tuning that's not important. If then the effect disappears it's
the CEM3340. Fortunately the CEM3340 are now in production again.

Best wishes
Dieter Doepfe