Unfortunately, I don't have access to a scope which makes it difficult to
diagnose <G>.

--Tom

----Original Message Follows----
From: "Paul D. DeRocco" <pderocco@...>
Reply-To: chromapolaris@yahoogroups.com
To: <chromapolaris@yahoogroups.com>
Subject: RE: [chromapolaris] Another topic... 2 oscillators out of tune.
Date: Fri, 4 Aug 2006 14:48:19 -0700

> From: Tom Krotchko
>
> I purchased a Polaris off the analog list less than a year ago.
> The thing
> is in almost perfect shape except that it appears two of the oscillators
> won't come in tune. The auto-tune says they are, but they
> aren't. You can
> tell when you play a scale, the 5th and 6th notes will just be off by a
> couple of tones.
>
> Now, some people have told me the problem is the row of caps. I
> pulled it
> apart, saw then, priced them etc. But I don't want to resolder a
> bunch of
> these things (I think there were twelve) and then find out it
> didn't make a
> difference.

Do you have access to a scope? You can tell if the problems are in that area
by looking at the outputs of the sample-and-hold buffers (Zx03 and Zx04). If
they have a sawtooth-like modulation on them of more than a few millivolts,
then the voltages on the caps are drooping. This usually means the caps are
leaky, but could also be the 4051 switches, or even the buffers themselves.

--

Ciao, Paul D. DeRocco
Paul mailto:pderocco@...