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Subject: RE: [chromapolaris] Q: a strange issue

From: "Paul D. DeRocco" <pderocco@...>
Date: 2012-05-16

> From: evening1
>
> Found a couple of odd issues after I sorted out my panel
> membrane problem. (I needed new connectors.)
>
> OSC1 & 2 seem to be affected by pulse with modulation even
> when they are set to saw.

That's a feature, not a bug. It's really a "saws" shape, as in the original
Chroma, where the width controls the phase between two sawteeth. This gives
you the inverse comb spectrum of the corresponding pulse. If you want a
plain saw, set the width to zero.

> The OSC2 pulse width mod slider is controlling the sweep
> speed, but the sweep slider doesn't do anything.
>
> I haven't dug into the schematics yet or done any calibration
> but I just thought that I'd throw this out to the list.
> I'm suspecting ICs have failed in some kind of odd way.

If any other sliders are mismatched, it could be one of the bits into the
4051 multiplexer that scans the sliders. Or it could be the 4051 itself.
This sort of thing usually makes itself obvious as soon as you poke a scope
probe into it.

> PS: My Polaris has metal faders, are there any suggested
> replacements?

Are any of them bad? The symptoms you describe don't sound like they
indicate bad sliders.

--

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