Cgs synth

It sounds like the 100k pull-down resistor across the base/emitter of the
transistor may not be soldered in propperly or is or the wrong value, or
perhaps the 100n itself is bad, or the wrong value. Failing all else, if it
works with the 100n shorted out, just run it that way. There is enough other
protection circuitry there for there to be no problems.

Ken

>
>Hello, just finished building the Bi N Tic filter/ osc. and I have a couple

of questions.

>
>I was getting quite a bit of slop on the Frequency panel control. It

basically only worked from about 12:00 on...

>
>I traced this down to the 100n cap between pin 6 of the 3140 and the 100k

that is connected to the base of the BC547`(of the collector is connected to
the CD4024).

>
>What was happening is that once the VCO went below a certain frequency, the

Saw wave would all but disappear AFTER the 100n cap. It was a good signal at
pin 6 of the 3140. The collect of the BC547 was just setting at 7V when the
frequency was set to (or beyond) this low point.

>
>I was able to rectify the situation (I think) by bridging the 100n. With

the 100n out of circuit I get good strong oscillations for the entire range
of the Freqency Panel control. The filter sonds really cool.

>
>Any insight as to what might be happening would be greatly appreciate. I do

not like the idea of removing something from the circit design in order to
get it to work.

>
>Thanx,
>
>Tony
>_________________________________________________________________
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Ltagline

>
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>
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>
>
>
>

_______________________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
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