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CV Expander Board - normal or not?

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CV Expander Board - normal or not?

Postby mic_test » Mon Aug 20, 2018 3:47 pm

Any life around this dusty ol' ghost town?

I finally get hold of an elusive CV Expansion Board for my Werkstatt.

But after installing it, I found that the Pulse Width adjustment knob in the VCO block no longer works. Fortunately, the EG or LFO modulation of pulse width in the VCO MOD block below does still work normally.

I removed the CV Board for comparison testing, and the Pulse adjustment knob doesn't work that way, either, now.

I don't have a 'scope, but I did record unfiltered waves to look at them in a DAW. The waveshapes all look nominal. Although it is stuck, so to speak, the pulse wave is at least stuck right in the middle for an even square wave. Modulation via LFO or EG runs it through a proper wide to narrow cycle.

The other observation I can offer is continuity tests on the CV Board -- not connected to anything, just on the table. The ground contacts all connect to ground and together, as one would expect.

On the tip contacts, all test separate, except:

VCF CV IN
VCO LIN FM IN
VCO EXP FM IN
LFO FM IN

all link together, somehow.

Which seems a little odd to me, but I don't know, maybe that is correct? How do yours test out?

If this were wrong, it seems like it should make huge, noticable problems, but everything seems to behave as I would expect. And I don't see any excess solder on the board, unless it is hidden somehow inside the pin strip?

And perhaps my issue with the PWM knob is just a crazy coincidence (certainly wouldn't be the first time I run into a deceptively crazy coincidence with music gear).

But as I say, I don't know if this is normal for these boards or not.

Any facts you can offer are welcome, thank you very much.
mic_test
 
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