Rhodes Chroma Polaris

I have a Polaris which works well except for one problem I hope is an easy fix.

The problem is that I can not completely turn off one oscillator.

I have no problem to disable oscillator #2 by selecting pulse and setting the pulse width to minimum (0%). 

However when I do the same on oscillator #1, I can still hear the pulse wave as it turns on and then off again at a very slow rate. The pulse width slider works and affects the pulse width however it is not shutting completely off at "0". 

I get the same effect if the pulse width is set to minimum (0%) or maximum (100%) and on all six oscillators.

Is there an adjustment I need to make to the pulse width slider?

Thanks