[sdiy] More ASM VCO Trouble

[Oren B. Leavitt]

Hello,

What are you using for the JFET that resets the integrator?
What type/value of capacitor are you using in the integrator?
What capacitor value are you using to set the reset 'on' time for the
LM311?

Possible theoretical causes:
The JFET that discharges the integrator cap may not be responsive enough
to reset the integrator completely.
Integrator capacitor should be ideally a polystyrene capacitor.
The capacitor that sets the reset pulse duration may be too small or out
of tolerance.

Oren

Default Jamerson wrote:

> HI All
> Finally got my ASM1 VCO's fired up...
> Sawtooth is working, but is too small,
> 4Vp-p and has a negative offset of -3V.
> The output from the 3140 is 2Vp-p with
> a positive offset of +4V. Therefore the
> the Square output is stuck at the -ve
> rail. Anyone's theory on this would
> greatly appreciated as my major school
> project (micro controlled CV keyboard)
> depends on it working, and time is short!
> Thanks again
> Marcus
> Melbourne Australia
>
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--
Oren Leavitt
oleavitt at ix.netcom.com