Cgs synth

>Okay - now I've checked continuity of all the traces leading to the
>TL072. Everything checks ok. Both outputs are at about 10-12vdc.
>The opamp is just going to the rails. Pin 3 is connected to
>ground. There is a nearly full-strength sawtooth right at pin 2 -
>that can't be right! The 200K resistor goes to the negative rail,
>and the 600K resistor is tying pins 1 and 2.

The 200k is providing an offset while the 600k is providing the gain -
supposedly. These aren't the values I specify.

>Here is something odd - when I measured resistance between pins 1
>and 2, I expected to see 600K ohms. I got a little over 200K ohms.
>I pulled the 600K resistor and the reading went up to 245K. I
>measured the DC resistance between pins 1 and 2 of a new TL072 and
>it's practically infinate. Is this supposed to be happening?

You are probably seeing the resistance via a secondary path - to ground or
something.

Ken
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