here is a good video of the back side of the board.
from what I can see, its using CD40106 (schmitt triggers) for the oscillators, with 74HC393 (counters)
Im familiar with the CD40106 as Ive been playing with the OMSynth from Bastl ( you can see how CD40106 are used here if your unfamiliar and interested , its cool stuff ).
there appears to be a set of resistor/capacitors and a pot, for each note of the scale... (R/C/P) the resistor/capacitors Id assume are for the basic tuning, then the pot will be for fine tuning....
Im intrigued to know what the counters do, I'm assuming something to do with the poly count.. 8 'oscillators' in the 40106, and there appears to be 1 counter for each 'note' (2 on each 393)
(presumably the surface changes resistance, as you move in the note, by a known amount?!)