> wonder if the CD40106BE is doing the osc sounds or if it belongs to
> the digital noise. as far
> as i think both unites are kind of seperate on one pcb.

The 40106 next to the two trimpots contains all the oscillators: the trimpots are used for the oscillators for the '2 oscillators' output; the other 4 oscs are fixed frequency. The other 40106 is used for the digital noise - one section for the oscillator, the others for inverting or simply buffers.

Tim