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What is likely to cause pitch drifts ?

2004-03-14 by gil_we

I own a vintage (70s) Korg MS-10. This little bastard works great 
excapt for casual pitch drifts. Sometimes it doesn't play the exact 
pitch when hitting a key, than hitting it once more will make the 
accurate pitch sound. This will also happen when using some "gilde", 
than when gliding to a note sometimes it won't target to the exact 
pitch...

Should I change all electrolytics ? how about ICs ? Which section 
shuold I look at ? VCA ? VCO ?

Thanks

Re: [PolySix] What is likely to cause pitch drifts ?

2004-03-14 by Stefan Rinass

Hi,

don\ufffdt know the MS-10 but maybe it\ufffds the failure of a dry capacitor which 
is connected between ground and +vcc. Afaik has the MS10 a CV out 
connector at the front panel which must be (in my opinion) directly 
connected to the resistor ladder of the Keyboard circuit. Did you 
measure this connector already while pressing one key twice (in order to 
find out if the CV actually changes)?

Or you should take a look into the Service manual (including circuit 
diagram)

http://www.phasereffect.com/pub/ms10.pdf        (880 kb)



Stef

Pure speculations.

Stef

gil_we wrote:

Show quoted textHide quoted text

>I own a vintage (70s) Korg MS-10. This little bastard works great 
>excapt for casual pitch drifts. Sometimes it doesn't play the exact 
>pitch when hitting a key, than hitting it once more will make the 
>accurate pitch sound. This will also happen when using some "gilde", 
>than when gliding to a note sometimes it won't target to the exact 
>pitch...
>
>Should I change all electrolytics ? how about ICs ? Which section 
>shuold I look at ? VCA ? VCO ?
>
>Thanks
>
>
>
>
>PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
>Yahoo! Groups Links
>
>
>
> 
>
>
>  
>

Re: [PolySix] What is likely to cause pitch drifts ?

2004-03-14 by Stefan Rinass

Ah, at the bottem of the Service manual is the Adjustment procedure. 
Didn\ufffdt saw that.

Stef

Stefan Rinass wrote:

Show quoted textHide quoted text

>Hi,
>
>don\ufffdt know the MS-10 but maybe it\ufffds the failure of a dry capacitor which 
>is connected between ground and +vcc. Afaik has the MS10 a CV out 
>connector at the front panel which must be (in my opinion) directly 
>connected to the resistor ladder of the Keyboard circuit. Did you 
>measure this connector already while pressing one key twice (in order to 
>find out if the CV actually changes)?
>
>Or you should take a look into the Service manual (including circuit 
>diagram)
>
>http://www.phasereffect.com/pub/ms10.pdf        (880 kb)
>
>
>
>Stef
>
>Pure speculations.
>
>Stef
>
>gil_we wrote:
>
>  
>
>>I own a vintage (70s) Korg MS-10. This little bastard works great 
>>excapt for casual pitch drifts. Sometimes it doesn't play the exact 
>>pitch when hitting a key, than hitting it once more will make the 
>>accurate pitch sound. This will also happen when using some "gilde", 
>>than when gliding to a note sometimes it won't target to the exact 
>>pitch...
>>
>>Should I change all electrolytics ? how about ICs ? Which section 
>>shuold I look at ? VCA ? VCO ?
>>
>>Thanks
>>
>>
>>
>>
>>PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
>>Yahoo! Groups Links
>>
>>
>>
>>
>>
>>
>> 
>>
>>    
>>
>
>
>
>
>PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
>Yahoo! Groups Links
>
>
>
> 
>
>
>  
>

Re: [PolySix] What is likely to cause pitch drifts ?

2004-03-14 by The Old Crow

Based on the MS-10 service manual pdf, I would suspect the sample/hold
section around parts F2/C4/IC3.  I would try replacing C4 first, then IC3,
and lastly FET2.

Crow
/**/

Re: What is likely to cause pitch drifts ?

2004-03-14 by gil_we

Thank !

I'll try that.


--- In PolySix@yahoogroups.com, The Old Crow <oldcrow@o...> wrote:
> 
>   Based on the MS-10 service manual pdf, I would suspect the 
sample/hold
> section around parts F2/C4/IC3.  I would try replacing C4 first, 
then IC3,

Show quoted textHide quoted text

> and lastly FET2.
> 
> Crow
> /**/

Discussion about the Korg PolySix synthesizer

What is likely to cause pitch drifts ?

What is likely to cause pitch drifts ?

Re: [PolySix] What is likely to cause pitch drifts ?

Re: [PolySix] What is likely to cause pitch drifts ?

Re: [PolySix] What is likely to cause pitch drifts ?

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