Odyssey VCO problem

[Brian McDonald]

Well, I'm still trying to fix my Odyssey (model 2800) VCO problem
(problem being that VCO 2 will not scale and its frequency range is much
different from 20Hz-20kHz - seems like it goes to like 40kHz, although I
didn't measure this).  I brought it to a local tech (Thang Ho at
Musicians Service Center in San Jose), who couldn't determine the exact
problem, but suggested that it may be the CD4011 chip (a quad NAND gate)
or the 2N5459 FET.  

Does this sound like a possibility?  Any other possibilities?  I found
replacement parts for these at Mouser, and figure if all the tech was
going to do was trying swapping parts and rescaling the VCO, that I
could just as easily do that.  These parts are pretty cheap.

I have already verified that it is not the Tempco resistor, which was a
good suggestion from an AHer.  I had a similar problem when I built the
ASM-1 (I left out the Tempco and the VCO scaling was way, way out of
range - like a few octaves in the range of three notes!).

thanks for any help!

brian

-- brian mcdonald ---- -- --- -- - --- -- --- --- - software engineer --
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