Discussion about the Korg PolySix synthesizer

hello,

I have a big problem with my polysix.

everything is fine, but when I turn it on, after a minute or two the
filter makes some strange modulations.. sounds a bit like fm ... I
will post an audio file soon...

I already changed the voice pcb from another polysix, and found out
that there's a problem with the digital board (klm367).

I already changed all electrolytic caps from the klm367, but no
improvement. I replaced the battery some days ago, the original
battery was only leaked a bit, but the pcb was clean and all traces on
the pcb are looking good.

do you have an idea what could be a reason for this problem...??

thanks,
mat

Yes, you have damaged traces. Check each one, one at a time. Use a
magnifying glass if you need to.

On 6/5/07, analog_audio01 <analog_audio01@yahoo.de> wrote:
> hello,
>
> I have a big problem with my polysix.
>
> everything is fine, but when I turn it on, after a minute or two the
> filter makes some strange modulations.. sounds a bit like fm ... I
> will post an audio file soon...
>
> I already changed the voice pcb from another polysix, and found out
> that there's a problem with the digital board (klm367).
>
> I already changed all electrolytic caps from the klm367, but no
> improvement. I replaced the battery some days ago, the original
> battery was only leaked a bit, but the pcb was clean and all traces on
> the pcb are looking good.
>
> do you have an idea what could be a reason for this problem...??
>
> thanks,
> mat
>
>
>
>
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> Yahoo! Groups Links
>
>
>
>


--
.sig
-Chromatest J. Pantsmaker
http://www.chromatest.net

Having repaired several dozen of these, I would say that visual inspection
of the traces is not sufficient; there can be damaged traces under the ICs,
and damaged through-holes -- none of which will be visible.

The only way (short of viewing each line with a scope) is to get hold of
the schematics and use a continuity probe to trace each of the data &
address lines.

Keep in mind that EVERY audio feature of the P6 has control voltages that
originate from the CPU board -- one damaged or shorted data line can
interfere with the functioning of any number of features (filter cutoff,
ADSR amount, etc).

~GMM


At 08:45 AM 6/5/2007, you wrote:

>Yes, you have damaged traces. Check each one, one at a time. Use a
>magnifying glass if you need to.
>
>On 6/5/07, analog_audio01
><<mailto:analog_audio01%40yahoo.de>analog_audio01@yahoo.de> wrote:
> > hello,
> >
> > I have a big problem with my polysix.
> >
> > everything is fine, but when I turn it on, after a minute or two the
> > filter makes some strange modulations.. sounds a bit like fm ... I
> > will post an audio file soon...
> >
> > I already changed the voice pcb from another polysix, and found out
> > that there's a problem with the digital board (klm367).
> >
> > I already changed all electrolytic caps from the klm367, but no
> > improvement. I replaced the battery some days ago, the original
> > battery was only leaked a bit, but the pcb was clean and all traces on
> > the pcb are looking good.
> >
> > do you have an idea what could be a reason for this problem...??
> >
> > thanks,
> > mat
> >
> >
> >
> >
> > PolySix "Digiest" Page:
> <http://www.acc.umu.se/~amber/Poly6>http://www.acc.umu.se/~amber/Poly6
> > Yahoo! Groups Links
> >
> >
> >
> >
>
>--
>.sig
>-Chromatest J. Pantsmaker
><http://www.chromatest.net>http://www.chromatest.net
>

[Non-text portions of this message have been removed]

thanks for your help!!

I'll recheck the board for bad traces and thru-holes today with my
multimeter... and hope to get rid of this problem..

mat

ok, I checked the klm361 (digital pcb)
all traces and thru-holes in the battery section are ok...
I measured them with my multimeter.

I made a sound example so that you can listen how bad my poly6 sounds:

http://www.cmaudio.net/poly6prob.mp3

as I wrote earlier in my thread the problem is on the klm 361 pcb (I
interchanged it with the board from a working p6 and then it was fine...)

I think the dc voltage from the digital board are not clean..
I already changed all electrolytic caps, but what should I do next?

change some ics?

or borrow a scope and measure the pins at the connectors? looking for
some voltages that could cause this modulations??


thanks for your help
mat

Did you check the continuity of the board connectors? I've seen
corrosion inside the connectors. Just do a simple continuity check
from the board on one side of the connector, to the other board on the
other side of the connector... The traces might be fine, but if the
voltages can't get to the traces, your sol.

On 6/21/07, analog_audio01 <analog_audio01@yahoo.de> wrote:
> ok, I checked the klm361 (digital pcb)
> all traces and thru-holes in the battery section are ok...
> I measured them with my multimeter.
>
> I made a sound example so that you can listen how bad my poly6 sounds:
>
> http://www.cmaudio.net/poly6prob.mp3
>
> as I wrote earlier in my thread the problem is on the klm 361 pcb (I
> interchanged it with the board from a working p6 and then it was fine...)
>
> I think the dc voltage from the digital board are not clean..
> I already changed all electrolytic caps, but what should I do next?
>
> change some ics?
>
> or borrow a scope and measure the pins at the connectors? looking for
> some voltages that could cause this modulations??
>
>
> thanks for your help
> mat
>
>
>
>
>
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> Yahoo! Groups Links
>
>
>
>


--
.sig
-Chromatest J. Pantsmaker
http://www.chromatest.net

thanks,

I'll try that, but I think it's not a connector problem,
when I switch the polysix on, everything is fine for a few minutes,
then these strange modulations starts... like you can hear in the mp3

mat

--- In PolySix@yahoogroups.com, "Chromatest J. Pantsmaker"
<chromatest@...> wrote:

>
> Did you check the continuity of the board connectors? I've seen
> corrosion inside the connectors. Just do a simple continuity check
> from the board on one side of the connector, to the other board on the
> other side of the connector... The traces might be fine, but if the
> voltages can't get to the traces, your sol.
>
> On 6/21/07, analog_audio01 <analog_audio01@...> wrote:
> > ok, I checked the klm361 (digital pcb)
> > all traces and thru-holes in the battery section are ok...
> > I measured them with my multimeter.
> >
> > I made a sound example so that you can listen how bad my poly6 sounds:
> >
> > http://www.cmaudio.net/poly6prob.mp3
> >
> > as I wrote earlier in my thread the problem is on the klm 361 pcb (I
> > interchanged it with the board from a working p6 and then it was

fine...)

> >
> > I think the dc voltage from the digital board are not clean..
> > I already changed all electrolytic caps, but what should I do next?
> >
> > change some ics?
> >
> > or borrow a scope and measure the pins at the connectors? looking for
> > some voltages that could cause this modulations??
> >
> >
> > thanks for your help
> > mat
> >
> >
> >
> >
> >
> > PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> > Yahoo! Groups Links
> >
> >
> >
> >
>
>
> --
> .sig
> -Chromatest J. Pantsmaker
> http://www.chromatest.net
>

I checked all the connectors, changed 2 ics near the battery and it
became much better.

when i turn on the unit the first 20-30 minutes everything works fine,
but when the p6 has completely warmed up, everything sounds total wierd...

are there any temperature sensitive parts that I should consider to
change? maybe the power supply..??

btw: when I don't close the lid, everything is ok.

thanks for your help.

mat


--- In PolySix@yahoogroups.com, "analog_audio01" <analog_audio01@...>
wrote:

>
> thanks,
>
> I'll try that, but I think it's not a connector problem,
> when I switch the polysix on, everything is fine for a few minutes,
> then these strange modulations starts... like you can hear in the mp3
>
> mat
>
> --- In PolySix@yahoogroups.com, "Chromatest J. Pantsmaker"
> <chromatest@> wrote:
> >
> > Did you check the continuity of the board connectors? I've seen
> > corrosion inside the connectors. Just do a simple continuity check
> > from the board on one side of the connector, to the other board on the
> > other side of the connector... The traces might be fine, but if the
> > voltages can't get to the traces, your sol.
> >
> > On 6/21/07, analog_audio01 <analog_audio01@> wrote:
> > > ok, I checked the klm361 (digital pcb)
> > > all traces and thru-holes in the battery section are ok...
> > > I measured them with my multimeter.
> > >
> > > I made a sound example so that you can listen how bad my poly6

sounds:

> > >
> > > http://www.cmaudio.net/poly6prob.mp3
> > >
> > > as I wrote earlier in my thread the problem is on the klm 361 pcb (I
> > > interchanged it with the board from a working p6 and then it was
> fine...)
> > >
> > > I think the dc voltage from the digital board are not clean..
> > > I already changed all electrolytic caps, but what should I do next?
> > >
> > > change some ics?
> > >
> > > or borrow a scope and measure the pins at the connectors?

looking for

> > > some voltages that could cause this modulations??
> > >
> > >
> > > thanks for your help
> > > mat
> > >
> > >
> > >
> > >
> > >
> > > PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> >
> >
> > --
> > .sig
> > -Chromatest J. Pantsmaker
> > http://www.chromatest.net
> >
>

It's just about always a good idea to replace any and all electrolytic
capacitors, as they do dry out with age. Having good beefy new
capacitors in the power supply should always increase performance.

I don't know if this will help with your problem or not, but if you're
spending this much time anyway....

On 7/9/07, analog_audio01 <analog_audio01@yahoo.de> wrote:
> I checked all the connectors, changed 2 ics near the battery and it
> became much better.
>
> when i turn on the unit the first 20-30 minutes everything works fine,
> but when the p6 has completely warmed up, everything sounds total wierd...
>
> are there any temperature sensitive parts that I should consider to
> change? maybe the power supply..??
>
> btw: when I don't close the lid, everything is ok.
>
> thanks for your help.
>
> mat
>
>
> --- In PolySix@yahoogroups.com, "analog_audio01" <analog_audio01@...>
> wrote:
> >
> > thanks,
> >
> > I'll try that, but I think it's not a connector problem,
> > when I switch the polysix on, everything is fine for a few minutes,
> > then these strange modulations starts... like you can hear in the mp3
> >
> > mat
> >
> > --- In PolySix@yahoogroups.com, "Chromatest J. Pantsmaker"
> > <chromatest@> wrote:
> > >
> > > Did you check the continuity of the board connectors? I've seen
> > > corrosion inside the connectors. Just do a simple continuity check
> > > from the board on one side of the connector, to the other board on the
> > > other side of the connector... The traces might be fine, but if the
> > > voltages can't get to the traces, your sol.
> > >
> > > On 6/21/07, analog_audio01 <analog_audio01@> wrote:
> > > > ok, I checked the klm361 (digital pcb)
> > > > all traces and thru-holes in the battery section are ok...
> > > > I measured them with my multimeter.
> > > >
> > > > I made a sound example so that you can listen how bad my poly6
> sounds:
> > > >
> > > > http://www.cmaudio.net/poly6prob.mp3
> > > >
> > > > as I wrote earlier in my thread the problem is on the klm 361 pcb (I
> > > > interchanged it with the board from a working p6 and then it was
> > fine...)
> > > >
> > > > I think the dc voltage from the digital board are not clean..
> > > > I already changed all electrolytic caps, but what should I do next?
> > > >
> > > > change some ics?
> > > >
> > > > or borrow a scope and measure the pins at the connectors?
> looking for
> > > > some voltages that could cause this modulations??
> > > >
> > > >
> > > > thanks for your help
> > > > mat
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> > > > Yahoo! Groups Links
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > > --
> > > .sig
> > > -Chromatest J. Pantsmaker
> > > http://www.chromatest.net
> > >
> >
>
>
>
>
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> Yahoo! Groups Links
>
>
>
>


--
.sig
-Chromatest J. Pantsmaker
http://www.chromatest.net

the best way to track down heat sensitive parts is to use something
like this:

http://www.crcind.com.au/catalogue.nsf/web_brands/Freeze+Spray?
openDocument

be very gentle, as you can damage parts that are on there way out...or
sometimes parts can 'fix themselves' permanently with a good
freezing :-)