[sdiy] ASM-1 VCO troubles another time

[Fortner Florian]

Hi list,

Excuse me for annoying everbody again with ASM-1 VCO problems, but I don't
know how to go on.

I've built the VCO on a selfmade PCB, and the Output of the Integrator
(CA3140) gives a strange high-frequency sawtooth (between 70 and 160 kHz
with a magnitude of ~1V and an offset of 4.5V), the Voltage on the gate of
the FET (I used a 2N3819 which has a slightly higher rdson) is a kind of
"rounded" rectangle, not spikes. The cool thing is, that when I touch the
18p Cap (C3) with my finger the freq. drops to the desired 8-10kHz and the
FET voltage becomes the spike-waveform. Any ideas what this could be? I
already double checked the board and defluxed it. 

regards,

flo