I just got it, the way the circuit works. At first it looked indecipherable but now i understand it, the nand gates for an oscillator, whose output is used both inverted and non-inverted and then used to select channel. The rest may ultimately serve a purpose though for the the simplest overview it can be seen as trim.
Now i just need to hope i didn't break the thing by toying with it, if it is as old an IC as i think then there stands a decent chance i did.