Discussion about the Korg PolySix synthesizer

There is a good scan of the service manual available for download at http://www.synfo.nl

Ben

On 17 aug. 2013, at 13:36, Frank Carvalho <dko4342@vip.cybercity.dk> wrote:

> And another thing:
> The copy of the schematics in the files section is very difficult to
> read to the point where I can not figure the component numbers, and I
> don't want to put this component in backwards. Can anyone tell me which
> pins of the PC-1 is LED plus and minus, and which are the resistor pins?
> One pin of the LED must be connected to R93, but is that the plus or the
> minus?
> 
> /Frank
>> My technician only had a VTL5C1, which does not exactly match the
>> characteristics as the VTL5C3 recommended. Can anyone suggest how a
>> VTL5C1 would behave in the P6 in place of the failing PC-1, and what
>> sort of resistor replacements may be needed. Someone suggested to use
>> a
>> trimpot in place of the R93, and adjust until it scales correctly. 
>> 
>> Thanks
>> 
>> /Frank
>> 
>> On Tue, 2013-08-13 at 17:00 -0400, backshall1 wrote:
>>> 
>>> Yes, that does sound like an opto-coupler issue. It's the P1501 chip
>>> on the
>>> oscillator board. It looks like a 6-pin DIP chip, but it only has 5
>>> pins and
>>> one of those isn't connected to anything, so it really has 4 pins
>> that
>>> are
>>> used. Current replacements are Silonex NSL32SR3 and the Vactrol
>> Vactec
>>> VTL5C3, and a couple of others in the Silonex and Vactrol families.
>>> You'll
>>> have to search the message threads to see what other people have
>> used,
>>> or
>>> check out the file "PC-1 opto replacement.txt" in the group files
>>> section.
>>> 
>>> Too bad there are no DIP package replacements available. All of
>> these
>>> parts
>>> are radial lead so you have to figure out which leads are the diode
>>> side and
>>> what the polarity is before installing. Also, R93 usually needs to
>> be
>>> changed, and it might take some experimenting to figure out what
>> value
>>> works
>>> best.
>>> 
>>> Don Backshall
>>> 
>>> _____ 
>>> 
>>> From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On
>>> Behalf Of
>>> Frank Carvalho
>>> Sent: Tuesday, August 13, 2013 4:43 PM
>>> To: PolySix@yahoogroups.com
>>> Subject: [PolySix] P6 scaling issue
>>> 
>>> Hello
>>> 
>>> I am sure this is a classic issue, but it just happened to me now,
>> and
>>> I
>>> need some advice.
>>> 
>>> My P6 has not been used for a while, and since electronic equipment
>>> should be turned on once in a while, I pulled it out to give it some
>>> time turned on. But in the meantime it has developed an issue with
>> the
>>> scaling of the octaves. Every octave has become about a semitone too
>>> wide. All the oscillators line up fine across the entire range, but
>>> the
>>> range is just scaled wrong.
>>> 
>>> I read suggestions that it may be an issue with an opto-coupler, and
>>> if
>>> that is the case, where is it located, and what modern day component
>>> may
>>> replace it?
>>> 
>>> If it is something else, please give me your suggestions.
>>> 
>>> And before you ask, the battery was replaced long ago, before it got
>>> bad.
>>> 
>>> Thanks
>>> 
>>> Frank Carvalho
>>> 
>>> [Non-text portions of this message have been removed]
>>> 
>>> 
>>> 
>>> 
>>> 
>> 
>> 
>> 
>> 
>> 
> 
> 
> 
> 
> ------------------------------------
> 
> Yahoo! Groups Links
> 
> 
>