Resolution:
= tested
= untested
FIX for pcb silkscreen failure for powersupply
cross one Ferrite on top pcb side - the ferrite on other pcb site (not shown here)
FIX for Hum issue on Speaker:
short out the 10Ω resistor and the 100p capacitor in the PSU section. E.g. just make a small bridge between the pad close to 10Ω and 100p as in the attached picture.
FIX for distorted Noise.
leave out the 2n5172 - use a bc337, - bend right leg to top, solder a 10K resistor in series to the 10uF cap.
FIX for Clock bleed on VCO pitch
at the moment 2 different solutions
one tested solution : leave out the 2n5172 in clock section (led driver for blinken lights), bridge 2 solder holes..
second solution (untested by me, but tested by one other user)
As suggested by Nordcore (many thanks), I swapped the clock's IC chip for a TL071, installed a 2n3906 PNP transistor and a resistor which measured 4k74
There is no more bleed from the clock to the VCO pitch.
In the pictures, I hope you can make out that base connects to the diode and is conveniently marked with an arrow. The emitter connects to +15V via the 4k74 resistor, +15V being tapped from one of the slider's pins. The collector connects to ground via a short insulated wire.
I had already removed and bridged the component-side transistor
