Archive of the former Yahoo!Groups mailing list: Discussion about the Korg PolySix synthesizer

Le jeudi, septembre 21, 2017, 5:46 PM, Tony McAdam swamp.gigs@googlemail.com [PolySix] <PolySix@yahoogroups.com> a écrit :

 

Hi - centre VR1, 2 and 3 and work with VR11 and VR15 (tune mid)... and the onto VR10 and the back to VR11 and 15...

Do this for one voice and repeat til it's scaled, then the other voices will be easy.

On Thu, Sep 21, 2017 at 2:40 PM, mr gham mrgham@yahoo.com [PolySix] <PolySix@yahoogroups.com> wrote:

 

I did find -13v at 

Ic18  .

I changed it with a working one ( I tested it before and have -3 v).

It partially solved the issue . Thanks 

I can reach a C.

But still I can tune the low or the high

But not together (from the same voice , I can t have c2 and c6 together bra cause the trim high don't allow to go till c6 from the key c6)  ... so I can tune right on an octave but not at the whole keyboard ...

+ i remarked that VR2 ( tune high , right ?) has no effect when I turn it. 

Can the issue come from there ?

Thanks 


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Le mercredi, septembre 20, 2017, 9:08 PM, mr gham mrgham@yahoo.com [PolySix] <PolySix@yahoogroups.com> a écrit :

 

Thanks 

I ll check that

On Wednesday, September 20, 2017 5:53 PM, "Tony McAdam swamp.gigs@googlemail.com [PolySix]" <PolySix@yahoogroups.com> wrote:

 

Hi - here's how to check the opto... http://huebnerie.de/blog/2013/ 07/polysix-photocoupler-myths/

"This leads to an eady way to check whether a tuning problem is related to the photocoupler circuit at all: measure the voltage on pin 7 of IC18. Within regulation it should be somewhat between -2 and -6 volts, -3 are more normal.
When the loop breaks open due to failure of the photocoupler or related parts, it will be stuck on the maximum negative output, something around -13 volts. There must always be a small current through the LED, otherwise the loop does not work and the TUNE HIGH preset has no effect!"

For the older daughterboard version it's pin 6 on IC18 as it's an 071 instead of an 072....

On Wed, Sep 20, 2017 at 3:44 PM, mr gham mrgham@yahoo.com [PolySix] <PolySix@yahoogroups.com> wrote:

 

Hi Tony,

This is a new 366


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Le mercredi, septembre 20, 2017, 4:28 PM, Tony McAdam swamp.gigs@googlemail.com [PolySix] <PolySix@yahoogroups.com> a écrit :

 

What version 366 board is it ? Sounds like an optocoupler problem...