Years ago, I had assembled a gnome kit, and almost got it working, when my mom accidentally threw it out... Long story, but I've been pining for one since. I recently got a half completed kit off to EBay, and finished it. It is almost working, but I have a strange problem that has me stumped. The VCO is oscillating at a very high rate, and refuses to slow down to the audio range. So far, all the components and wiring check out, but I had to provide a new IC, which is a good LM3900. I did replace several of the 2.2uf caps, as they seemed noisy, and that didn't fix anything or change the symptom besides reducing noise.

I can see that the Range control seems to be varying the voltage between 0 and over 15 volts. Can someone share some experience about what to look for. I am afraid that if the transistors are bad, I'm gonna have a tough time. Also tried a different 470pf cap, but no change there either.

HELP! The VCA, Noise, VCF are all fine - and I can make wind noises, and gun shots all day long, just no tones!

Thanks!

Maybe it's Q3 which mounts on the panel with connections to the power switch and it being a different transistor than is shown in the manual (PN2712 vs 2N2712)...

viewtopic.php?f=29&t=200

Schematics with DC voltage test points:

Wow - an awesome tidbit - thanks a lot - I'll recheck all these orientations tomorrow. I sure hope that is it!