Discussion about the Korg PolySix synthesizer

I've been recovering this one, found in the flea market. Overall it 
had about 8-9 different faults that I fixed, leaving two problems.

The first is a bad SSM2056 chip which I need to find. The second i 
probably inherent in the discrete ciruit of the second oscillator.

Upon powering it up, that particular oscillator will be out of tune, 
till it gets to its max. internal temperature where the tuning of 
that VCO is geting more or less - stable.

All other oscillators are immediately in tune, no matter what is the 
temperatue inside the machine.

I, of course, tried to figure out what the bad component is by 
blowing with a straw on each and each of the suspected compnents, but 
blowingon every component on the circuit of that oscialltor which 
seems to be pitch related, seems to effect the pitch.

I also tried to switch transistors between the bad oscillator and 
another (working one) but the problem persisted.

Does anyone have any other idea / direction ?

Thanks

Hi,

I only have the schematics for the MK I; which I do not know whether
it is similar to the MK II. Which VCO has the problem? Is it VCO-1 or
VCO-2 or both? If it is both then hacve a look at the hold capacitors 
after the VCO CV demux IC15 (a 4051) on KLM-301 board.  These are the
caps C25 - C32.

Good luck,

Johannes


gil_we wrote:

> I've been recovering this one, found in the flea market. Overall it 
> had about 8-9 different faults that I fixed, leaving two problems.
> 
> The first is a bad SSM2056 chip which I need to find. The second i 
> probably inherent in the discrete ciruit of the second oscillator.
> 
> Upon powering it up, that particular oscillator will be out of tune, 
> till it gets to its max. internal temperature where the tuning of 
> that VCO is geting more or less - stable.
> 
> All other oscillators are immediately in tune, no matter what is the 
> temperatue inside the machine.
> 
> I, of course, tried to figure out what the bad component is by 
> blowing with a straw on each and each of the suspected compnents, but 
> blowingon every component on the circuit of that oscialltor which 
> seems to be pitch related, seems to effect the pitch.
> 
> I also tried to switch transistors between the bad oscillator and 
> another (working one) but the problem persisted.
> 
> Does anyone have any other idea / direction ?
> 
> Thanks
> 
> 
> 
> 
> 
> 
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
>

Thanks very much !

The tuning is bad on both VCO1 and VCO2 of that oscillator (although 
it seems more extreme on VCO2).

I uploaded the schematics diagram for the VCO board to the files 
section - what would be the caps to check on that one ?

Thanks again.


--- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...> 
wrote:
>
> Hi,
> 
> I only have the schematics for the MK I; which I do not know whether
> it is similar to the MK II. Which VCO has the problem? Is it VCO-1 
or
> VCO-2 or both? If it is both then hacve a look at the hold 
capacitors 
> after the VCO CV demux IC15 (a 4051) on KLM-301 board.  These are 
the
> caps C25 - C32.
> 
> Good luck,
> 
> Johannes
> 
> 
> gil_we wrote:
> > I've been recovering this one, found in the flea market. Overall 
it 
> > had about 8-9 different faults that I fixed, leaving two problems.
> > 
> > The first is a bad SSM2056 chip which I need to find. The second 
i 
> > probably inherent in the discrete ciruit of the second oscillator.
> > 
> > Upon powering it up, that particular oscillator will be out of 
tune, 
> > till it gets to its max. internal temperature where the tuning of 
> > that VCO is geting more or less - stable.
> > 
> > All other oscillators are immediately in tune, no matter what is 
the 
> > temperatue inside the machine.
> > 
> > I, of course, tried to figure out what the bad component is by 
> > blowing with a straw on each and each of the suspected compnents, 
but 

> > blowingon every component on the circuit of that oscialltor which 
> > seems to be pitch related, seems to effect the pitch.
> > 
> > I also tried to switch transistors between the bad oscillator and 
> > another (working one) but the problem persisted.
> > 
> > Does anyone have any other idea / direction ?
> > 
> > Thanks
> > 
> > 
> > 
> > 
> > 
> > 
> > PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
> > Yahoo! Groups Links
> > 
> > 
> > 
> >  
> > 
> > 
> >
>

Hi,

The caps are Cx10 ... where x is the voice number. On the schematics
only voice #7 is drawn in detail, so you can see C710. Maybe it is not
the cap but the accompanying resistor (R739), or the demux (IC8).

This is a great machine. Two really independant VCOs!

Johannes


gil_we wrote:

> Thanks very much !
> 
> The tuning is bad on both VCO1 and VCO2 of that oscillator (although 
> it seems more extreme on VCO2).
> 
> I uploaded the schematics diagram for the VCO board to the files 
> section - what would be the caps to check on that one ?
> 
> Thanks again.
> 
> 
> --- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...> 
> wrote:
> 
>>Hi,
>>
>>I only have the schematics for the MK I; which I do not know whether
>>it is similar to the MK II. Which VCO has the problem? Is it VCO-1 or
>>VCO-2 or both? If it is both then have a look at the hold capacitors 
>>after the VCO CV demux IC15 (a 4051) on KLM-301 board.  These are the
>>caps C25 - C32.
>>
>>Good luck,
>>
>>Johannes
>>
>>
>>gil_we wrote:
>>
>>>I've been recovering this one, found in the flea market. Overall it 
>>>had about 8-9 different faults that I fixed, leaving two problems.
>>>
>>>The first is a bad SSM2056 chip which I need to find. The second i 
>>>probably inherent in the discrete ciruit of the second oscillator.
>>>
>>>Upon powering it up, that particular oscillator will be out of tune, 
>>>till it gets to its max. internal temperature where the tuning of 
>>>that VCO is geting more or less - stable.
>>>
>>>All other oscillators are immediately in tune, no matter what is the 
>>>temperatue inside the machine.
>>>
>>>I, of course, tried to figure out what the bad component is by 
>>>blowing with a straw on each and each of the suspected compnents, but 
>>>blowing on every component on the circuit of that oscialltor which 
>>>seems to be pitch related, seems to effect the pitch.
>>>
>>>I also tried to switch transistors between the bad oscillator and 
>>>another (working one) but the problem persisted.
>>>
>>>Does anyone have any other idea / direction ?
>>>
>>>Thanks
>>>
>>>
>>>
>>>
>>
>> 
>> 
> 
> 
>

Thanks !

The Cx10 and Rx39 have been already replaced to no avail.

By IC8 are you refering to ICx08 ? it's a 4558 opamp.

btw, I now see that I had to replace Rx36 with a slightly different
value because even after the machine is warm enough, with the
original value the related VCO still cannot get tuned with the other
oscillators, not matter how you set the VCO tuning trimmers.

Thanks again.


--- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...> 
wrote:
>
> Hi,
> 
> The caps are Cx10 ... where x is the voice number. On the schematics
> only voice #7 is drawn in detail, so you can see C710. Maybe it is 
not
> the cap but the accompanying resistor (R739), or the demux (IC8).
> 
> This is a great machine. Two really independant VCOs!
> 
> Johannes
> 
> 
> gil_we wrote:
> > Thanks very much !
> > 
> > The tuning is bad on both VCO1 and VCO2 of that oscillator 
(although 
> > it seems more extreme on VCO2).
> > 
> > I uploaded the schematics diagram for the VCO board to the files 
> > section - what would be the caps to check on that one ?
> > 
> > Thanks again.
> > 
> > 
> > --- In PolySix@yahoogroups.com, Johannes Hausensteiner 
<johau@g...> 
> > wrote:
> > 
> >>Hi,
> >>
> >>I only have the schematics for the MK I; which I do not know 
whether
> >>it is similar to the MK II. Which VCO has the problem? Is it VCO-
1 or
> >>VCO-2 or both? If it is both then have a look at the hold 
capacitors 
> >>after the VCO CV demux IC15 (a 4051) on KLM-301 board.  These are 
the
> >>caps C25 - C32.
> >>
> >>Good luck,
> >>
> >>Johannes
> >>
> >>
> >>gil_we wrote:
> >>
> >>>I've been recovering this one, found in the flea market. Overall 
it 
> >>>had about 8-9 different faults that I fixed, leaving two 
problems.
> >>>
> >>>The first is a bad SSM2056 chip which I need to find. The second 
i 
> >>>probably inherent in the discrete ciruit of the second 
oscillator.
> >>>
> >>>Upon powering it up, that particular oscillator will be out of 
tune, 
> >>>till it gets to its max. internal temperature where the tuning 
of 
> >>>that VCO is geting more or less - stable.
> >>>
> >>>All other oscillators are immediately in tune, no matter what is 
the 
> >>>temperatue inside the machine.
> >>>
> >>>I, of course, tried to figure out what the bad component is by 
> >>>blowing with a straw on each and each of the suspected 
compnents, but 
> >>>blowing on every component on the circuit of that oscialltor 
which 
> >>>seems to be pitch related, seems to effect the pitch.
> >>>
> >>>I also tried to switch transistors between the bad oscillator 
and 

> >>>another (working one) but the problem persisted.
> >>>
> >>>Does anyone have any other idea / direction ?
> >>>
> >>>Thanks
> >>>
> >>>
> >>>
> >>>
> >>
> >> 
> >> 
> > 
> > 
> >
>

If you already replaced Rx39/Cx10 then the only thing in common
for both VCOs in one voice is ICx11 (TL072).  THe value of Rx39
is not very critical unless it is very different to the nominal
value of 1k

 > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
No, I mean IC8, which is a 4051.  It is common to all voices; it
demultiplexes the CV for the VCOs

Johannes


gil_we wrote:

> Thanks !
> 
> The Cx10 and Rx39 have been already replaced to no avail.
> 
> By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> 
> btw, I now see that I had to replace Rx36 with a slightly different
> value because even after the machine is warm enough, with the
> original value the related VCO still cannot get tuned with the other
> oscillators, not matter how you set the VCO tuning trimmers.
> 
> Thanks again.
> 
> --- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...> 
> wrote:
> 
>>Hi,
>>
>>The caps are Cx10 ... where x is the voice number. On the schematics
>>only voice #7 is drawn in detail, so you can see C710. Maybe it is 
> 
> not
> 
>>the cap but the accompanying resistor (R739), or the demux (IC8).
>>
>>This is a great machine. Two really independant VCOs!
>>
>>Johannes
>>
>>
>>gil_we wrote:
>>
>>>Thanks very much !
>>>
>>>The tuning is bad on both VCO1 and VCO2 of that oscillator 
> 
> (although 
> 
>>>it seems more extreme on VCO2).
>>>
>>>I uploaded the schematics diagram for the VCO board to the files 
>>>section - what would be the caps to check on that one ?
>>>
>>>Thanks again.
>>>
>>>
>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner 
> 
> <johau@g...> 
> 
>>>wrote:
>>>
>>>
>>>>Hi,
>>>>
>>>>I only have the schematics for the MK I; which I do not know 
> 
> whether
> 
>>>>it is similar to the MK II. Which VCO has the problem? Is it VCO-
> 
> 1 or
> 
>>>>VCO-2 or both? If it is both then have a look at the hold 
> 
> capacitors 
> 
>>>>after the VCO CV demux IC15 (a 4051) on KLM-301 board.  These are 
> 
> the
> 
>>>>caps C25 - C32.
>>>>
>>>>Good luck,
>>>>
>>>>Johannes
>>>>
>>>>
>>>>gil_we wrote:
>>>>
>>>>
>>>>>I've been recovering this one, found in the flea market. Overall 
> 
> it 
> 
>>>>>had about 8-9 different faults that I fixed, leaving two 
> 
> problems.
> 
>>>>>The first is a bad SSM2056 chip which I need to find. The second 
> 
> i 
> 
>>>>>probably inherent in the discrete ciruit of the second 
> 
> oscillator.
> 
>>>>>Upon powering it up, that particular oscillator will be out of 
> 
> tune, 
> 
>>>>>till it gets to its max. internal temperature where the tuning 
> 
> of 
> 
>>>>>that VCO is geting more or less - stable.
>>>>>
>>>>>All other oscillators are immediately in tune, no matter what is 
> 
> the 
> 
>>>>>temperatue inside the machine.
>>>>>
>>>>>I, of course, tried to figure out what the bad component is by 
>>>>>blowing with a straw on each and each of the suspected 
> 
> compnents, but 
> 
>>>>>blowing on every component on the circuit of that oscialltor 
> 
> which 
> 
>>>>>seems to be pitch related, seems to effect the pitch.
>>>>>
>>>>>I also tried to switch transistors between the bad oscillator 
> 
> and 
> 
>>>>>another (working one) but the problem persisted.
>>>>>
>>>>>Does anyone have any other idea / direction ?
>>>>>
>>>>>Thanks
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>
>>>
> 
> 
> 
> 
> 
> 
> 
> 
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
>

You know what ?... now I relaize I replaced IC8 and ICx11 as well !

What if the problem is related with only one of the VCOs...? lets say 
VCO1. What would you check/replace ?


--- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...> 
wrote:
>
> If you already replaced Rx39/Cx10 then the only thing in common
> for both VCOs in one voice is ICx11 (TL072).  THe value of Rx39
> is not very critical unless it is very different to the nominal
> value of 1k
> 
>  > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> No, I mean IC8, which is a 4051.  It is common to all voices; it
> demultiplexes the CV for the VCOs
> 
> Johannes
> 
> 
> gil_we wrote:
> > Thanks !
> > 
> > The Cx10 and Rx39 have been already replaced to no avail.
> > 
> > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> > 
> > btw, I now see that I had to replace Rx36 with a slightly 
different
> > value because even after the machine is warm enough, with the
> > original value the related VCO still cannot get tuned with the 
other
> > oscillators, not matter how you set the VCO tuning trimmers.
> > 
> > Thanks again.
> > 
> > --- In PolySix@yahoogroups.com, Johannes Hausensteiner 
<johau@g...> 
> > wrote:
> > 
> >>Hi,
> >>
> >>The caps are Cx10 ... where x is the voice number. On the 
schematics
> >>only voice #7 is drawn in detail, so you can see C710. Maybe it 
is 
> > 
> > not
> > 
> >>the cap but the accompanying resistor (R739), or the demux (IC8).
> >>
> >>This is a great machine. Two really independant VCOs!
> >>
> >>Johannes
> >>
> >>
> >>gil_we wrote:
> >>
> >>>Thanks very much !
> >>>
> >>>The tuning is bad on both VCO1 and VCO2 of that oscillator 
> > 
> > (although 
> > 
> >>>it seems more extreme on VCO2).
> >>>
> >>>I uploaded the schematics diagram for the VCO board to the files 
> >>>section - what would be the caps to check on that one ?
> >>>
> >>>Thanks again.
> >>>
> >>>
> >>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner 
> > 
> > <johau@g...> 
> > 
> >>>wrote:
> >>>
> >>>
> >>>>Hi,
> >>>>
> >>>>I only have the schematics for the MK I; which I do not know 
> > 
> > whether
> > 
> >>>>it is similar to the MK II. Which VCO has the problem? Is it 
VCO-
> > 
> > 1 or
> > 
> >>>>VCO-2 or both? If it is both then have a look at the hold 
> > 
> > capacitors 
> > 
> >>>>after the VCO CV demux IC15 (a 4051) on KLM-301 board.  These 
are 
> > 
> > the
> > 
> >>>>caps C25 - C32.
> >>>>
> >>>>Good luck,
> >>>>
> >>>>Johannes
> >>>>
> >>>>
> >>>>gil_we wrote:
> >>>>
> >>>>
> >>>>>I've been recovering this one, found in the flea market. 
Overall 
> > 
> > it 
> > 
> >>>>>had about 8-9 different faults that I fixed, leaving two 
> > 
> > problems.
> > 
> >>>>>The first is a bad SSM2056 chip which I need to find. The 
second 
> > 
> > i 
> > 
> >>>>>probably inherent in the discrete ciruit of the second 
> > 
> > oscillator.
> > 
> >>>>>Upon powering it up, that particular oscillator will be out of 
> > 
> > tune, 
> > 
> >>>>>till it gets to its max. internal temperature where the tuning 
> > 
> > of 
> > 
> >>>>>that VCO is geting more or less - stable.
> >>>>>
> >>>>>All other oscillators are immediately in tune, no matter what 
is 

> > 
> > the 
> > 
> >>>>>temperatue inside the machine.
> >>>>>
> >>>>>I, of course, tried to figure out what the bad component is by 
> >>>>>blowing with a straw on each and each of the suspected 
> > 
> > compnents, but 
> > 
> >>>>>blowing on every component on the circuit of that oscialltor 
> > 
> > which 
> > 
> >>>>>seems to be pitch related, seems to effect the pitch.
> >>>>>
> >>>>>I also tried to switch transistors between the bad oscillator 
> > 
> > and 
> > 
> >>>>>another (working one) but the problem persisted.
> >>>>>
> >>>>>Does anyone have any other idea / direction ?
> >>>>>
> >>>>>Thanks
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>>
> >>>
> >>>
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
> > Yahoo! Groups Links
> > 
> > 
> > 
> >  
> > 
> > 
> > 
> >
>

1) If you experience that one voice has this problem, and within this
    one voice it is both VCOs then it is very likely that the reason
    lies in a component or signal which is common to both VCOs. Otherwise
    there must be *two* problems which show similar effect.

2) Please don't rely on anything that anyone did any-when. If there are
    components which have been replaced before, this is no guarantee
    that they are working now.  Maybe this was 5, 8, 10 years ago?  Maybe
    there is a reason behind why they failed then, which makes them fail
    again?  Maybe the guy doing the "repair" built in a bug (e.g. short
    circuit, ...)?

You can measure the VCO CV e.g. on ICx11/pin5 on a good voice and on the
bad one.  Do it in this way that you first play a low note and then a
high one to see the step in the CV.  This would be done best with a
storage oscilloscope, which you probably do not have; but if the "step"
is so slow that you can hear it, you should be able to see the
difference on the scope.  How does the CV change?  Can you see a ramp
(which is to be supposed when you hear kind of a "portamento" on this
one voice)?  Or a step?  Is it equal going up vs. going down?  How is
the situation when you set the trimpots to a similar position as on a
good voice?  Does it sound too high?  Too low?  Is the scale
approximately correct?  - Very difficult to debug this via email ...

If you cannot find it, you may start to disconnect "unnecessary"
circuitry and go to the absolut minimum circuit for one VCO (which is
ICx11 and the 4 bipolar transistors plus caps and resistors; up to the
FET).  Maybe it's the FETs, but it is very unlikely that both FETs
have a similar problem, only in one voice.


Good luck,

Johannes


gil_we wrote:

> You know what ?... now I relaize I replaced IC8 and ICx11 as well !
> 
> Any other idea you can think of ?
> 
> What you're saying is that as long as the problem exist on both VCO 
> it must be caused by a common part to both VCO ?...
> 
> I'll try the ICx11 ... any other idea you can think of ?
> 
> 
> 
> 
> 
> --- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...> 
> wrote:
> 
>>If you already replaced Rx39/Cx10 then the only thing in common
>>for both VCOs in one voice is ICx11 (TL072).  THe value of Rx39
>>is not very critical unless it is very different to the nominal
>>value of 1k
>>
>> > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
>>No, I mean IC8, which is a 4051.  It is common to all voices; it
>>demultiplexes the CV for the VCOs
>>
>>Johannes
>>
>>
>>gil_we wrote:
>>
>>>Thanks !
>>>
>>>The Cx10 and Rx39 have been already replaced to no avail.
>>>
>>>By IC8 are you refering to ICx08 ? it's a 4558 opamp.
>>>
>>>btw, I now see that I had to replace Rx36 with a slightly 
> 
> different
> 
>>>value because even after the machine is warm enough, with the
>>>original value the related VCO still cannot get tuned with the 
> 
> other
> 
>>>oscillators, not matter how you set the VCO tuning trimmers.
>>>
>>>Thanks again.
>>>
>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner 
> 
> <johau@g...> 
> 
>>>wrote:
>>>
>>>
>>>>Hi,
>>>>
>>>>The caps are Cx10 ... where x is the voice number. On the 
> 
> schematics
> 
>>>>only voice #7 is drawn in detail, so you can see C710. Maybe it 
> 
> is 
> 
>>>not
>>>
>>>
>>>>the cap but the accompanying resistor (R739), or the demux (IC8).
>>>>
>>>>This is a great machine. Two really independant VCOs!
>>>>
>>>>Johannes
>>>>
>>>>
>>>>gil_we wrote:
>>>>
>>>>
>>>>>Thanks very much !
>>>>>
>>>>>The tuning is bad on both VCO1 and VCO2 of that oscillator 
>>>
>>>(although 
>>>
>>>
>>>>>it seems more extreme on VCO2).
>>>>>
>>>>>I uploaded the schematics diagram for the VCO board to the files 
>>>>>section - what would be the caps to check on that one ?
>>>>>
>>>>>Thanks again.
>>>>>
>>>>>
>>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner 
>>>
>>><johau@g...> 
>>>
>>>
>>>>>wrote:
>>>>>
>>>>>
>>>>>
>>>>>>Hi,
>>>>>>
>>>>>>I only have the schematics for the MK I; which I do not know 
>>>
>>>whether
>>>
>>>
>>>>>>it is similar to the MK II. Which VCO has the problem? Is it 
> 
> VCO-
> 
>>>1 or
>>>
>>>
>>>>>>VCO-2 or both? If it is both then have a look at the hold 
>>>
>>>capacitors 
>>>
>>>
>>>>>>after the VCO CV demux IC15 (a 4051) on KLM-301 board.  These 
> 
> are 
> 
>>>the
>>>
>>>
>>>>>>caps C25 - C32.
>>>>>>
>>>>>>Good luck,
>>>>>>
>>>>>>Johannes
>>>>>>
>>>>>>
>>>>>>gil_we wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>>I've been recovering this one, found in the flea market. 
> 
> Overall 
> 
>>>it 
>>>
>>>
>>>>>>>had about 8-9 different faults that I fixed, leaving two 
>>>
>>>problems.
>>>
>>>
>>>>>>>The first is a bad SSM2056 chip which I need to find. The 
> 
> second 
> 
>>>i 
>>>
>>>
>>>>>>>probably inherent in the discrete ciruit of the second 
>>>
>>>oscillator.
>>>
>>>
>>>>>>>Upon powering it up, that particular oscillator will be out of 
>>>
>>>tune, 
>>>
>>>
>>>>>>>till it gets to its max. internal temperature where the tuning 
>>>
>>>of 
>>>
>>>
>>>>>>>that VCO is geting more or less - stable.
>>>>>>>
>>>>>>>All other oscillators are immediately in tune, no matter what 
> 
> is 
> 
>>>the 
>>>
>>>
>>>>>>>temperatue inside the machine.
>>>>>>>
>>>>>>>I, of course, tried to figure out what the bad component is by 
>>>>>>>blowing with a straw on each and each of the suspected 
>>>
>>>compnents, but 
>>>
>>>
>>>>>>>blowing on every component on the circuit of that oscialltor 
>>>
>>>which 
>>>
>>>
>>>>>>>seems to be pitch related, seems to effect the pitch.
>>>>>>>
>>>>>>>I also tried to switch transistors between the bad oscillator 
>>>
>>>and 
>>>
>>>
>>>>>>>another (working one) but the problem persisted.
>>>>>>>
>>>>>>>Does anyone have any other idea / direction ?
>>>>>>>
>>>>>>>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
> 
> 
> 
>  
> 
> 
>

If it is only one VCO, then things are different. It may be the cap
(C709), which I do not believe because it is a polypropylene type,
which have very good long term stability.  I would go for the 3
transistors plus diode which form some kind of "unijunction" type
of behaviour: ICx11 together with Qx10 converts the CV to a constant
current, which in turn creates a voltage ramp through Cx9.  When the
voltage across Cx9 reaches a certain value Qx2, Qx4, Qx6, Dx2 "fire"
and short Cx9, and you have a sawtooth wave.  This is a very similar
design as in the MS series (MS-10, MS-20), even the values are similar.
First disconnect (remove) the flipflop (ICx10), which generates the
sub-octave waves and is not necessary for the 4' wave. Just in case ...
Then put the oscilloscope to the collector of Qx10 and watch the ramp.
(both good and bad voice).  If the ramp is bad (not straight) then
probably Qx10 is faulty, but it could be ICx11 or Cx9.  But i do not
think that this will be the case.

Good luck,

Johannes



gil_we wrote:

> You know what ?... now I relaize I replaced IC8 and ICx11 as well !
> 
> What if the problem is related with only one of the VCOs...? lets say 
> VCO1. What would you check/replace ?
> 
> 
> --- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...> 
> wrote:
> 
>>If you already replaced Rx39/Cx10 then the only thing in common
>>for both VCOs in one voice is ICx11 (TL072).  THe value of Rx39
>>is not very critical unless it is very different to the nominal
>>value of 1k
>>
>> > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
>>No, I mean IC8, which is a 4051.  It is common to all voices; it
>>demultiplexes the CV for the VCOs
>>
>>Johannes
>>
>>
>>gil_we wrote:
>>
>>>Thanks !
>>>
>>>The Cx10 and Rx39 have been already replaced to no avail.
>>>
>>>By IC8 are you refering to ICx08 ? it's a 4558 opamp.
>>>
>>>btw, I now see that I had to replace Rx36 with a slightly 
> 
> different
> 
>>>value because even after the machine is warm enough, with the
>>>original value the related VCO still cannot get tuned with the 
> 
> other
> 
>>>oscillators, not matter how you set the VCO tuning trimmers.
>>>
>>>Thanks again.
>>>
>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner 
> 
> <johau@g...> 
> 
>>>wrote:
>>>
>>>
>>>>Hi,
>>>>
>>>>The caps are Cx10 ... where x is the voice number. On the 
> 
> schematics
> 
>>>>only voice #7 is drawn in detail, so you can see C710. Maybe it 
> 
> is 
> 
>>>not
>>>
>>>
>>>>the cap but the accompanying resistor (R739), or the demux (IC8).
>>>>
>>>>This is a great machine. Two really independant VCOs!
>>>>
>>>>Johannes
>>>>
>>>>
>>>>gil_we wrote:
>>>>
>>>>
>>>>>Thanks very much !
>>>>>
>>>>>The tuning is bad on both VCO1 and VCO2 of that oscillator 
>>>
>>>(although 
>>>
>>>
>>>>>it seems more extreme on VCO2).
>>>>>
>>>>>I uploaded the schematics diagram for the VCO board to the files 
>>>>>section - what would be the caps to check on that one ?
>>>>>
>>>>>Thanks again.
>>>>>
>>>>>
>>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner 
>>>
>>><johau@g...> 
>>>
>>>
>>>>>wrote:
>>>>>
>>>>>
>>>>>
>>>>>>Hi,
>>>>>>
>>>>>>I only have the schematics for the MK I; which I do not know 
>>>
>>>whether
>>>
>>>
>>>>>>it is similar to the MK II. Which VCO has the problem? Is it 
> 
> VCO-
> 
>>>1 or
>>>
>>>
>>>>>>VCO-2 or both? If it is both then have a look at the hold 
>>>
>>>capacitors 
>>>
>>>
>>>>>>after the VCO CV demux IC15 (a 4051) on KLM-301 board.  These 
> 
> are 
> 
>>>the
>>>
>>>
>>>>>>caps C25 - C32.
>>>>>>
>>>>>>Good luck,
>>>>>>
>>>>>>Johannes
>>>>>>
>>>>>>
>>>>>>gil_we wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>>I've been recovering this one, found in the flea market. 
> 
> Overall 
> 
>>>it 
>>>
>>>
>>>>>>>had about 8-9 different faults that I fixed, leaving two 
>>>
>>>problems.
>>>
>>>
>>>>>>>The first is a bad SSM2056 chip which I need to find. The 
> 
> second 
> 
>>>i 
>>>
>>>
>>>>>>>probably inherent in the discrete ciruit of the second 
>>>
>>>oscillator.
>>>
>>>
>>>>>>>Upon powering it up, that particular oscillator will be out of 
>>>
>>>tune, 
>>>
>>>
>>>>>>>till it gets to its max. internal temperature where the tuning 
>>>
>>>of 
>>>
>>>
>>>>>>>that VCO is geting more or less - stable.
>>>>>>>
>>>>>>>All other oscillators are immediately in tune, no matter what 
> 
> is 
> 
>>>the 
>>>
>>>
>>>>>>>temperatue inside the machine.
>>>>>>>
>>>>>>>I, of course, tried to figure out what the bad component is by 
>>>>>>>blowing with a straw on each and each of the suspected 
>>>
>>>compnents, but 
>>>
>>>
>>>>>>>blowing on every component on the circuit of that oscialltor 
>>>
>>>which 
>>>
>>>
>>>>>>>seems to be pitch related, seems to effect the pitch.
>>>>>>>
>>>>>>>I also tried to switch transistors between the bad oscillator 
>>>
>>>and 
>>>
>>>
>>>>>>>another (working one) but the problem persisted.
>>>>>>>
>>>>>>>Does anyone have any other idea / direction ?
>>>>>>>
>>>>>>>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
> 
> 
> 
>  
> 
> 
>

replace them again?  Sometimes (and it will always bite you) you put in a bunk part as a replacement.. then you spend all week looking for something else, saying "it can't be X!  I replaced X"..

----- Original Message -----
From: gil_we <gil_we@yahoo.com>
To: PolySix@yahoogroups.com
Subject: [PolySix] Re: Trident MKII - one oscillator is out of tune
Date: Tue, 06 Dec 2005 21:51:15 -0000

> 
> You know what ?... now I relaize I replaced IC8 and ICx11 as well !
> 
> Any other idea you can think of ?
> 
> 
> 
> 
> --- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...>
> wrote:
> >
> > If you already replaced Rx39/Cx10 then the only thing in common
> > for both VCOs in one voice is ICx11 (TL072).  THe value of Rx39
> > is not very critical unless it is very different to the nominal
> > value of 1k
> >
> >  > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> > No, I mean IC8, which is a 4051.  It is common to all voices; it
> > demultiplexes the CV for the VCOs
> >
> > Johannes
> >
> >
> > gil_we wrote:
> > > Thanks !
> > > > The Cx10 and Rx39 have been already replaced to no avail.
> > > > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> > > > btw, I now see that I had to replace Rx36 with a slightly
> different
> > > value because even after the machine is warm enough, with the
> > > original value the related VCO still cannot get tuned with the
> other
> > > oscillators, not matter how you set the VCO tuning trimmers.
> > > > Thanks again.
> > > > --- In PolySix@yahoogroups.com, Johannes Hausensteiner
> <johau@g...>
> > > wrote:
> > > >>Hi,
> > >>
> > >>The caps are Cx10 ... where x is the voice number. On the
> schematics
> > >>only voice #7 is drawn in detail, so you can see C710. Maybe it
> is
> > > > not
> > > >>the cap but the accompanying resistor (R739), or the demux (IC8).
> > >>
> > >>This is a great machine. Two really independant VCOs!
> > >>
> > >>Johannes
> > >>
> > >>
> > >>gil_we wrote:
> > >>
> > >>>Thanks very much !
> > >>>
> > >>>The tuning is bad on both VCO1 and VCO2 of that oscillator > > 
> > (although > >>>it seems more extreme on VCO2).
> > >>>
> > >>>I uploaded the schematics diagram for the VCO board to the 
> > files >>>section - what would be the caps to check on that one ?
> > >>>
> > >>>Thanks again.
> > >>>
> > >>>
> > >>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner > > 
> > <johau@g...> > >>>wrote:
> > >>>
> > >>>
> > >>>>Hi,
> > >>>>
> > >>>>I only have the schematics for the MK I; which I do not know > > whether
> > > >>>>it is similar to the MK II. Which VCO has the problem? Is it
> VCO-
> > > > 1 or
> > > >>>>VCO-2 or both? If it is both then have a look at the hold > 
> > > capacitors > >>>>after the VCO CV demux IC15 (a 4051) on 
> > KLM-301 board.  These
> are
> > > > the
> > > >>>>caps C25 - C32.
> > >>>>
> > >>>>Good luck,
> > >>>>
> > >>>>Johannes
> > >>>>
> > >>>>
> > >>>>gil_we wrote:
> > >>>>
> > >>>>
> > >>>>>I've been recovering this one, found in the flea market.
> Overall
> > > > it > >>>>>had about 8-9 different faults that I fixed, 
> > leaving two > > problems.
> > > >>>>>The first is a bad SSM2056 chip which I need to find. The
> second
> > > > i > >>>>>probably inherent in the discrete ciruit of the 
> > second > > oscillator.
> > > >>>>>Upon powering it up, that particular oscillator will be 
> > out of > > tune, > >>>>>till it gets to its max. internal 
> > temperature where the tuning > > of > >>>>>that VCO is geting 
> > more or less - stable.
> > >>>>>
> > >>>>>All other oscillators are immediately in tune, no matter what
> is
> > > > the > >>>>>temperatue inside the machine.
> > >>>>>
> > >>>>>I, of course, tried to figure out what the bad component is 
> > by >>>>>blowing with a straw on each and each of the suspected > 
> > > compnents, but > >>>>>blowing on every component on the circuit 
> > of that oscialltor > > which > >>>>>seems to be pitch related, 
> > seems to effect the pitch.
> > >>>>>
> > >>>>>I also tried to switch transistors between the bad 
> > oscillator > > and > >>>>>another (working one) but the problem 
> > persisted.
> > >>>>>
> > >>>>>Does anyone have any other idea / direction ?
> > >>>>>
> > >>>>>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
> 
> 
> 
> 



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

Thanks guys !

There was something strange going on.... After writing my previous 
mail I ran over a few components with a "freeze" spray, among them 
the transistors and caps area of both VCOs on the problematic 
oscillator and the R40 component (what looks like a mutli-leg 
transistor but I guess is a multi-resistor ?)

Suddenly, two things happen (which still happen if I turn the machine 
off for a few hours and back on... regardless internal temperature):

1. The bad oscillator is no more out of tune !

2. The entire scale has changed - i.e the gap between each note to 
the one that follows it is larger (there is more than one octave gap 
between C4 and C5 for example)

But that made me recall that when I got hte unit there was not tuning 
issue at all, and the bad tuning problem on the second oscillator 
only started once I started servicing the machine)

Strange huh ?

Could it be R40 that is defective ? does that make sense ?

Thanks again !





--- In PolySix@yahoogroups.com, "Chromatest J. Pantsmaker" 
<chromatest@g...> wrote:
>
> 
> 
> replace them again?  Sometimes (and it will always bite you) you 
put in a bunk part as a replacement.. then you spend all week looking 
for something else, saying "it can't be X!  I replaced X"..
> 
> 
> ----- Original Message -----
> From: gil_we <gil_we@y...>
> To: PolySix@yahoogroups.com
> Subject: [PolySix] Re: Trident MKII - one oscillator is out of tune
> Date: Tue, 06 Dec 2005 21:51:15 -0000
> 
> > 
> > You know what ?... now I relaize I replaced IC8 and ICx11 as 
well !
> > 
> > Any other idea you can think of ?
> > 
> > 
> > 
> > 
> > --- In PolySix@yahoogroups.com, Johannes Hausensteiner 
<johau@g...>
> > wrote:
> > >
> > > If you already replaced Rx39/Cx10 then the only thing in common
> > > for both VCOs in one voice is ICx11 (TL072).  THe value of Rx39
> > > is not very critical unless it is very different to the nominal
> > > value of 1k
> > >
> > >  > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> > > No, I mean IC8, which is a 4051.  It is common to all voices; it
> > > demultiplexes the CV for the VCOs
> > >
> > > Johannes
> > >
> > >
> > > gil_we wrote:
> > > > Thanks !
> > > > > The Cx10 and Rx39 have been already replaced to no avail.
> > > > > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> > > > > btw, I now see that I had to replace Rx36 with a slightly
> > different
> > > > value because even after the machine is warm enough, with the
> > > > original value the related VCO still cannot get tuned with the
> > other
> > > > oscillators, not matter how you set the VCO tuning trimmers.
> > > > > Thanks again.
> > > > > --- In PolySix@yahoogroups.com, Johannes Hausensteiner
> > <johau@g...>
> > > > wrote:
> > > > >>Hi,
> > > >>
> > > >>The caps are Cx10 ... where x is the voice number. On the
> > schematics
> > > >>only voice #7 is drawn in detail, so you can see C710. Maybe 
it
> > is
> > > > > not
> > > > >>the cap but the accompanying resistor (R739), or the demux 
(IC8).
> > > >>
> > > >>This is a great machine. Two really independant VCOs!
> > > >>
> > > >>Johannes
> > > >>
> > > >>
> > > >>gil_we wrote:
> > > >>
> > > >>>Thanks very much !
> > > >>>
> > > >>>The tuning is bad on both VCO1 and VCO2 of that oscillator > 
> 
> > > (although > >>>it seems more extreme on VCO2).
> > > >>>
> > > >>>I uploaded the schematics diagram for the VCO board to the 
> > > files >>>section - what would be the caps to check on that one ?
> > > >>>
> > > >>>Thanks again.
> > > >>>
> > > >>>
> > > >>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner > > 
> > > <johau@g...> > >>>wrote:
> > > >>>
> > > >>>
> > > >>>>Hi,
> > > >>>>
> > > >>>>I only have the schematics for the MK I; which I do not 
know > > whether
> > > > >>>>it is similar to the MK II. Which VCO has the problem? Is 
it
> > VCO-
> > > > > 1 or
> > > > >>>>VCO-2 or both? If it is both then have a look at the hold 
> 
> > > > capacitors > >>>>after the VCO CV demux IC15 (a 4051) on 
> > > KLM-301 board.  These
> > are
> > > > > the
> > > > >>>>caps C25 - C32.
> > > >>>>
> > > >>>>Good luck,
> > > >>>>
> > > >>>>Johannes
> > > >>>>
> > > >>>>
> > > >>>>gil_we wrote:
> > > >>>>
> > > >>>>
> > > >>>>>I've been recovering this one, found in the flea market.
> > Overall
> > > > > it > >>>>>had about 8-9 different faults that I fixed, 
> > > leaving two > > problems.
> > > > >>>>>The first is a bad SSM2056 chip which I need to find. The
> > second
> > > > > i > >>>>>probably inherent in the discrete ciruit of the 
> > > second > > oscillator.
> > > > >>>>>Upon powering it up, that particular oscillator will be 
> > > out of > > tune, > >>>>>till it gets to its max. internal 
> > > temperature where the tuning > > of > >>>>>that VCO is geting 
> > > more or less - stable.
> > > >>>>>
> > > >>>>>All other oscillators are immediately in tune, no matter 
what
> > is
> > > > > the > >>>>>temperatue inside the machine.
> > > >>>>>
> > > >>>>>I, of course, tried to figure out what the bad component 
is 
> > > by >>>>>blowing with a straw on each and each of the suspected 
> 
> > > > compnents, but > >>>>>blowing on every component on the 
circuit 

> > > of that oscialltor > > which > >>>>>seems to be pitch related, 
> > > seems to effect the pitch.
> > > >>>>>
> > > >>>>>I also tried to switch transistors between the bad 
> > > oscillator > > and > >>>>>another (working one) but the problem 
> > > persisted.
> > > >>>>>
> > > >>>>>Does anyone have any other idea / direction ?
> > > >>>>>
> > > >>>>>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
> > 
> > 
> > 
> > 
> 
> 
> 
> .sig
> -Chromatest J. Pantsmaker
> http://www.chromatest.net
>

ooops... the multileg component is IC6, not R40


--- In PolySix@yahoogroups.com, "gil_we" <gil_we@y...> wrote:
>
> Thanks guys !
> 
> There was something strange going on.... After writing my previous 
> mail I ran over a few components with a "freeze" spray, among them 
> the transistors and caps area of both VCOs on the problematic 
> oscillator and the R40 component (what looks like a mutli-leg 
> transistor but I guess is a multi-resistor ?)
> 
> Suddenly, two things happen (which still happen if I turn the 
machine 
> off for a few hours and back on... regardless internal temperature):
> 
> 1. The bad oscillator is no more out of tune !
> 
> 2. The entire scale has changed - i.e the gap between each note to 
> the one that follows it is larger (there is more than one octave 
gap 
> between C4 and C5 for example)
> 
> But that made me recall that when I got hte unit there was not 
tuning 
> issue at all, and the bad tuning problem on the second oscillator 
> only started once I started servicing the machine)
> 
> Strange huh ?
> 
> Could it be R40 that is defective ? does that make sense ?
> 
> Thanks again !
> 
> 
> 
> 
> 
> --- In PolySix@yahoogroups.com, "Chromatest J. Pantsmaker" 
> <chromatest@g...> wrote:
> >
> > 
> > 
> > replace them again?  Sometimes (and it will always bite you) you 
> put in a bunk part as a replacement.. then you spend all week 
looking 
> for something else, saying "it can't be X!  I replaced X"..
> > 
> > 
> > ----- Original Message -----
> > From: gil_we <gil_we@y...>
> > To: PolySix@yahoogroups.com
> > Subject: [PolySix] Re: Trident MKII - one oscillator is out of 
tune
> > Date: Tue, 06 Dec 2005 21:51:15 -0000
> > 
> > > 
> > > You know what ?... now I relaize I replaced IC8 and ICx11 as 
> well !
> > > 
> > > Any other idea you can think of ?
> > > 
> > > 
> > > 
> > > 
> > > --- In PolySix@yahoogroups.com, Johannes Hausensteiner 
> <johau@g...>
> > > wrote:
> > > >
> > > > If you already replaced Rx39/Cx10 then the only thing in 
common
> > > > for both VCOs in one voice is ICx11 (TL072).  THe value of 
Rx39
> > > > is not very critical unless it is very different to the 
nominal
> > > > value of 1k
> > > >
> > > >  > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> > > > No, I mean IC8, which is a 4051.  It is common to all voices; 
it
> > > > demultiplexes the CV for the VCOs
> > > >
> > > > Johannes
> > > >
> > > >
> > > > gil_we wrote:
> > > > > Thanks !
> > > > > > The Cx10 and Rx39 have been already replaced to no avail.
> > > > > > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> > > > > > btw, I now see that I had to replace Rx36 with a slightly
> > > different
> > > > > value because even after the machine is warm enough, with 
the
> > > > > original value the related VCO still cannot get tuned with 
the
> > > other
> > > > > oscillators, not matter how you set the VCO tuning trimmers.
> > > > > > Thanks again.
> > > > > > --- In PolySix@yahoogroups.com, Johannes Hausensteiner
> > > <johau@g...>
> > > > > wrote:
> > > > > >>Hi,
> > > > >>
> > > > >>The caps are Cx10 ... where x is the voice number. On the
> > > schematics
> > > > >>only voice #7 is drawn in detail, so you can see C710. 
Maybe 
> it
> > > is
> > > > > > not
> > > > > >>the cap but the accompanying resistor (R739), or the 
demux 
> (IC8).
> > > > >>
> > > > >>This is a great machine. Two really independant VCOs!
> > > > >>
> > > > >>Johannes
> > > > >>
> > > > >>
> > > > >>gil_we wrote:
> > > > >>
> > > > >>>Thanks very much !
> > > > >>>
> > > > >>>The tuning is bad on both VCO1 and VCO2 of that oscillator 
> 
> > 
> > > > (although > >>>it seems more extreme on VCO2).
> > > > >>>
> > > > >>>I uploaded the schematics diagram for the VCO board to the 
> > > > files >>>section - what would be the caps to check on that 
one ?
> > > > >>>
> > > > >>>Thanks again.
> > > > >>>
> > > > >>>
> > > > >>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner > > 
> > > > <johau@g...> > >>>wrote:
> > > > >>>
> > > > >>>
> > > > >>>>Hi,
> > > > >>>>
> > > > >>>>I only have the schematics for the MK I; which I do not 
> know > > whether
> > > > > >>>>it is similar to the MK II. Which VCO has the problem? 
Is 
> it
> > > VCO-
> > > > > > 1 or
> > > > > >>>>VCO-2 or both? If it is both then have a look at the 
hold 
> > 
> > > > > capacitors > >>>>after the VCO CV demux IC15 (a 4051) on 
> > > > KLM-301 board.  These
> > > are
> > > > > > the
> > > > > >>>>caps C25 - C32.
> > > > >>>>
> > > > >>>>Good luck,
> > > > >>>>
> > > > >>>>Johannes
> > > > >>>>
> > > > >>>>
> > > > >>>>gil_we wrote:
> > > > >>>>
> > > > >>>>
> > > > >>>>>I've been recovering this one, found in the flea market.
> > > Overall
> > > > > > it > >>>>>had about 8-9 different faults that I fixed, 
> > > > leaving two > > problems.
> > > > > >>>>>The first is a bad SSM2056 chip which I need to find. 
The
> > > second
> > > > > > i > >>>>>probably inherent in the discrete ciruit of the 
> > > > second > > oscillator.
> > > > > >>>>>Upon powering it up, that particular oscillator will 
be 
> > > > out of > > tune, > >>>>>till it gets to its max. internal 
> > > > temperature where the tuning > > of > >>>>>that VCO is geting 
> > > > more or less - stable.
> > > > >>>>>
> > > > >>>>>All other oscillators are immediately in tune, no matter 
> what
> > > is
> > > > > > the > >>>>>temperatue inside the machine.
> > > > >>>>>
> > > > >>>>>I, of course, tried to figure out what the bad component 
> is 
> > > > by >>>>>blowing with a straw on each and each of the 
suspected 
> > 
> > > > > compnents, but > >>>>>blowing on every component on the 
> circuit 
> > > > of that oscialltor > > which > >>>>>seems to be pitch 
related, 
> > > > seems to effect the pitch.
> > > > >>>>>
> > > > >>>>>I also tried to switch transistors between the bad 
> > > > oscillator > > and > >>>>>another (working one) but the 
problem 

> > > > persisted.
> > > > >>>>>
> > > > >>>>>Does anyone have any other idea / direction ?
> > > > >>>>>
> > > > >>>>>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
> > > 
> > > 
> > > 
> > > 
> > 
> > 
> > 
> > .sig
> > -Chromatest J. Pantsmaker
> > http://www.chromatest.net
> >
>

The "multileg component" probably is the dual transistor for the
antilog amplifier.  This is one of the most critical stages in terms
of note frequency.  It has an exponential transfer characteristic,
which means that a tiny variation at the input may cause a huge at
the output.  Applying a freeze spray definitely will have a large
effect on the tune of the instrument, but all voices are affected
equally, because the antilog conversion is applied to the multi-
plexed CV.

gil_we wrote:

> ooops... the multileg component is IC6, not R40
> 
> 
> --- In PolySix@yahoogroups.com, "gil_we" <gil_we@y...> wrote:
> 
>>Thanks guys !
>>
>>There was something strange going on.... After writing my previous 
>>mail I ran over a few components with a "freeze" spray, among them 
>>the transistors and caps area of both VCOs on the problematic 
>>oscillator and the R40 component (what looks like a mutli-leg 
>>transistor but I guess is a multi-resistor ?)
>>
>>Suddenly, two things happen (which still happen if I turn the 
> 
> machine 
> 
>>off for a few hours and back on... regardless internal temperature):
>>
>>1. The bad oscillator is no more out of tune !
>>
>>2. The entire scale has changed - i.e the gap between each note to 
>>the one that follows it is larger (there is more than one octave 
> 
> gap 
> 
>>between C4 and C5 for example)
>>
>>But that made me recall that when I got hte unit there was not 
> 
> tuning 
> 
>>issue at all, and the bad tuning problem on the second oscillator 
>>only started once I started servicing the machine)
>>
>>Strange huh ?
>>
>>Could it be R40 that is defective ? does that make sense ?
>>
>>Thanks again !
>>
>>
>>
>>
>>
>>--- In PolySix@yahoogroups.com, "Chromatest J. Pantsmaker" 
>><chromatest@g...> wrote:
>>
>>>
>>>
>>>replace them again?  Sometimes (and it will always bite you) you 
>>
>>put in a bunk part as a replacement.. then you spend all week 
> 
> looking 
> 
>>for something else, saying "it can't be X!  I replaced X"..
>>
>>>
>>>----- Original Message -----
>>>From: gil_we <gil_we@y...>
>>>To: PolySix@yahoogroups.com
>>>Subject: [PolySix] Re: Trident MKII - one oscillator is out of 
> 
> tune
> 
>>>Date: Tue, 06 Dec 2005 21:51:15 -0000
>>>
>>>
>>>>You know what ?... now I relaize I replaced IC8 and ICx11 as 
>>
>>well !
>>
>>>>Any other idea you can think of ?
>>>>
>>>>
>>>>
>>>>
>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner 
>>
>><johau@g...>
>>
>>>>wrote:
>>>>
>>>>>If you already replaced Rx39/Cx10 then the only thing in 
> 
> common
> 
>>>>>for both VCOs in one voice is ICx11 (TL072).  THe value of 
> 
> Rx39
> 
>>>>>is not very critical unless it is very different to the 
> 
> nominal
> 
>>>>>value of 1k
>>>>>
>>>>> > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
>>>>>No, I mean IC8, which is a 4051.  It is common to all voices; 
> 
> it
> 
>>>>>demultiplexes the CV for the VCOs
>>>>>
>>>>>Johannes
>>>>>
>>>>>
>>>>>gil_we wrote:
>>>>>
>>>>>>Thanks !
>>>>>>
>>>>>>>The Cx10 and Rx39 have been already replaced to no avail.
>>>>>>>By IC8 are you refering to ICx08 ? it's a 4558 opamp.
>>>>>>>btw, I now see that I had to replace Rx36 with a slightly
>>>>
>>>>different
>>>>
>>>>>>value because even after the machine is warm enough, with 
> 
> the
> 
>>>>>>original value the related VCO still cannot get tuned with 
> 
> the
> 
>>>>other
>>>>
>>>>>>oscillators, not matter how you set the VCO tuning trimmers.
>>>>>>
>>>>>>>Thanks again.
>>>>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner
>>>>
>>>><johau@g...>
>>>>
>>>>>>wrote:
>>>>>>
>>>>>>>>Hi,
>>>>>>>
>>>>>>>The caps are Cx10 ... where x is the voice number. On the
>>>>
>>>>schematics
>>>>
>>>>>>>only voice #7 is drawn in detail, so you can see C710. 
> 
> Maybe 
> 
>>it
>>
>>>>is
>>>>
>>>>>>>not
>>>>>>>
>>>>>>>>the cap but the accompanying resistor (R739), or the 
> 
> demux 
> 
>>(IC8).
>>
>>>>>>>This is a great machine. Two really independant VCOs!
>>>>>>>
>>>>>>>Johannes
>>>>>>>
>>>>>>>
>>>>>>>gil_we wrote:
>>>>>>>
>>>>>>>
>>>>>>>>Thanks very much !
>>>>>>>>
>>>>>>>>The tuning is bad on both VCO1 and VCO2 of that oscillator 
>>
>>>>>(although > >>>it seems more extreme on VCO2).
>>>>>
>>>>>>>>I uploaded the schematics diagram for the VCO board to the 
>>>>>
>>>>>files >>>section - what would be the caps to check on that 
> 
> one ?
> 
>>>>>>>>Thanks again.
>>>>>>>>
>>>>>>>>
>>>>>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner > > 
>>>>>
>>>>><johau@g...> > >>>wrote:
>>>>>
>>>>>>>>
>>>>>>>>>Hi,
>>>>>>>>>
>>>>>>>>>I only have the schematics for the MK I; which I do not 
>>
>>know > > whether
>>
>>>>>>>>>>it is similar to the MK II. Which VCO has the problem? 
> 
> Is 
> 
>>it
>>
>>>>VCO-
>>>>
>>>>>>>1 or
>>>>>>>
>>>>>>>>>>VCO-2 or both? If it is both then have a look at the 
> 
> hold 
> 
>>>>>>capacitors > >>>>after the VCO CV demux IC15 (a 4051) on 
>>>>>
>>>>>KLM-301 board.  These
>>>>
>>>>are
>>>>
>>>>>>>the
>>>>>>>
>>>>>>>>>>caps C25 - C32.
>>>>>>>>>
>>>>>>>>>Good luck,
>>>>>>>>>
>>>>>>>>>Johannes
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>gil_we wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>>I've been recovering this one, found in the flea market.
>>>>
>>>>Overall
>>>>
>>>>>>>it > >>>>>had about 8-9 different faults that I fixed, 
>>>>>
>>>>>leaving two > > problems.
>>>>>
>>>>>>>>>>>The first is a bad SSM2056 chip which I need to find. 
> 
> The
> 
>>>>second
>>>>
>>>>>>>i > >>>>>probably inherent in the discrete ciruit of the 
>>>>>
>>>>>second > > oscillator.
>>>>>
>>>>>>>>>>>Upon powering it up, that particular oscillator will 
> 
> be 
> 
>>>>>out of > > tune, > >>>>>till it gets to its max. internal 
>>>>>temperature where the tuning > > of > >>>>>that VCO is geting 
>>>>>more or less - stable.
>>>>>
>>>>>>>>>>All other oscillators are immediately in tune, no matter 
>>
>>what
>>
>>>>is
>>>>
>>>>>>>the > >>>>>temperatue inside the machine.
>>>>>>>
>>>>>>>>>>I, of course, tried to figure out what the bad component 
>>
>>is 
>>
>>>>>by >>>>>blowing with a straw on each and each of the 
> 
> suspected 
> 
>>>>>>compnents, but > >>>>>blowing on every component on the 
>>
>>circuit 
>>
>>>>>of that oscialltor > > which > >>>>>seems to be pitch 
> 
> related, 
> 
>>>>>seems to effect the pitch.
>>>>>
>>>>>>>>>>I also tried to switch transistors between the bad 
>>>>>
>>>>>oscillator > > and > >>>>>another (working one) but the 
> 
> problem 
> 
>>>>>persisted.
>>>>>
>>>>>>>>>>Does anyone have any other idea / direction ?
>>>>>>>>>>
>>>>>>>>>>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
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>.sig
>>>-Chromatest J. Pantsmaker
>>>http://www.chromatest.net
>>>
>>
> 
> 
> 
> 
> 
> 
> 
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
>

Now I see what happened... I guess that was a big mistake using the 
freeze spray on such a sensitive circuit.

The problem is that I already even readjusted VR3, VR4 and VR5... So 
even if and when the bad componet gets to its natural state the synth 
will be out of tune ! shouldn't have touched it from the start ...

Johannes, 

1. can the dual transistor get back to its initial, natural state ? 
Maybe if I let the machine work a few days (so the components 
can "recover" from the freeze harm - maybe by warming up ?)

2. Do VR4 (Antilog Freq.), VR3 (Antilog Width) and VR5 (Antilog 
Offset) act like the VR6 (Hi Tune), VR7 (Mid Tune) and VR5 (Low 
Tune) - on the Polysix new-version ? So basically if and when the 
components are ok, I should be able to tune it the same way you tune 
a Polysix ?

3. Last question - should the TH1 heat sensor be located just over 
the multitransistor in general ? it was leaning over the circuit 
board when I check it out, just realized it is a sesnor...

Thanks very much, I SHOULD fix that one it's one of a monster 
beautifully sounding instrument !



--- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...> 
wrote:
>
> The "multileg component" probably is the dual transistor for the
> antilog amplifier.  This is one of the most critical stages in terms
> of note frequency.  It has an exponential transfer characteristic,
> which means that a tiny variation at the input may cause a huge at
> the output.  Applying a freeze spray definitely will have a large
> effect on the tune of the instrument, but all voices are affected
> equally, because the antilog conversion is applied to the multi-
> plexed CV.
> 
> gil_we wrote:
> > ooops... the multileg component is IC6, not R40
> > 
> > 
> > --- In PolySix@yahoogroups.com, "gil_we" <gil_we@y...> wrote:
> > 
> >>Thanks guys !
> >>
> >>There was something strange going on.... After writing my 
previous 
> >>mail I ran over a few components with a "freeze" spray, among 
them 
> >>the transistors and caps area of both VCOs on the problematic 
> >>oscillator and the R40 component (what looks like a mutli-leg 
> >>transistor but I guess is a multi-resistor ?)
> >>
> >>Suddenly, two things happen (which still happen if I turn the 
> > 
> > machine 
> > 
> >>off for a few hours and back on... regardless internal 
temperature):
> >>
> >>1. The bad oscillator is no more out of tune !
> >>
> >>2. The entire scale has changed - i.e the gap between each note 
to 

> >>the one that follows it is larger (there is more than one octave 
> > 
> > gap 
> > 
> >>between C4 and C5 for example)
> >>
> >>But that made me recall that when I got hte unit there was not 
> > 
> > tuning 
> > 
> >>issue at all, and the bad tuning problem on the second oscillator 
> >>only started once I started servicing the machine)
> >>
> >>Strange huh ?
> >>
> >>Could it be R40 that is defective ? does that make sense ?
> >>
> >>Thanks again !
> >>
> >>
> >>
> >>
> >>
> >>--- In PolySix@yahoogroups.com, "Chromatest J. Pantsmaker" 
> >><chromatest@g...> wrote:
> >>
> >>>
> >>>
> >>>replace them again?  Sometimes (and it will always bite you) you 
> >>
> >>put in a bunk part as a replacement.. then you spend all week 
> > 
> > looking 
> > 
> >>for something else, saying "it can't be X!  I replaced X"..
> >>
> >>>
> >>>----- Original Message -----
> >>>From: gil_we <gil_we@y...>
> >>>To: PolySix@yahoogroups.com
> >>>Subject: [PolySix] Re: Trident MKII - one oscillator is out of 
> > 
> > tune
> > 
> >>>Date: Tue, 06 Dec 2005 21:51:15 -0000
> >>>
> >>>
> >>>>You know what ?... now I relaize I replaced IC8 and ICx11 as 
> >>
> >>well !
> >>
> >>>>Any other idea you can think of ?
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner 
> >>
> >><johau@g...>
> >>
> >>>>wrote:
> >>>>
> >>>>>If you already replaced Rx39/Cx10 then the only thing in 
> > 
> > common
> > 
> >>>>>for both VCOs in one voice is ICx11 (TL072).  THe value of 
> > 
> > Rx39
> > 
> >>>>>is not very critical unless it is very different to the 
> > 
> > nominal
> > 
> >>>>>value of 1k
> >>>>>
> >>>>> > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> >>>>>No, I mean IC8, which is a 4051.  It is common to all voices; 
> > 
> > it
> > 
> >>>>>demultiplexes the CV for the VCOs
> >>>>>
> >>>>>Johannes
> >>>>>
> >>>>>
> >>>>>gil_we wrote:
> >>>>>
> >>>>>>Thanks !
> >>>>>>
> >>>>>>>The Cx10 and Rx39 have been already replaced to no avail.
> >>>>>>>By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> >>>>>>>btw, I now see that I had to replace Rx36 with a slightly
> >>>>
> >>>>different
> >>>>
> >>>>>>value because even after the machine is warm enough, with 
> > 
> > the
> > 
> >>>>>>original value the related VCO still cannot get tuned with 
> > 
> > the
> > 
> >>>>other
> >>>>
> >>>>>>oscillators, not matter how you set the VCO tuning trimmers.
> >>>>>>
> >>>>>>>Thanks again.
> >>>>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner
> >>>>
> >>>><johau@g...>
> >>>>
> >>>>>>wrote:
> >>>>>>
> >>>>>>>>Hi,
> >>>>>>>
> >>>>>>>The caps are Cx10 ... where x is the voice number. On the
> >>>>
> >>>>schematics
> >>>>
> >>>>>>>only voice #7 is drawn in detail, so you can see C710. 
> > 
> > Maybe 
> > 
> >>it
> >>
> >>>>is
> >>>>
> >>>>>>>not
> >>>>>>>
> >>>>>>>>the cap but the accompanying resistor (R739), or the 
> > 
> > demux 
> > 
> >>(IC8).
> >>
> >>>>>>>This is a great machine. Two really independant VCOs!
> >>>>>>>
> >>>>>>>Johannes
> >>>>>>>
> >>>>>>>
> >>>>>>>gil_we wrote:
> >>>>>>>
> >>>>>>>
> >>>>>>>>Thanks very much !
> >>>>>>>>
> >>>>>>>>The tuning is bad on both VCO1 and VCO2 of that oscillator 
> >>
> >>>>>(although > >>>it seems more extreme on VCO2).
> >>>>>
> >>>>>>>>I uploaded the schematics diagram for the VCO board to the 
> >>>>>
> >>>>>files >>>section - what would be the caps to check on that 
> > 
> > one ?
> > 
> >>>>>>>>Thanks again.
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner > > 
> >>>>>
> >>>>><johau@g...> > >>>wrote:
> >>>>>
> >>>>>>>>
> >>>>>>>>>Hi,
> >>>>>>>>>
> >>>>>>>>>I only have the schematics for the MK I; which I do not 
> >>
> >>know > > whether
> >>
> >>>>>>>>>>it is similar to the MK II. Which VCO has the problem? 
> > 
> > Is 
> > 
> >>it
> >>
> >>>>VCO-
> >>>>
> >>>>>>>1 or
> >>>>>>>
> >>>>>>>>>>VCO-2 or both? If it is both then have a look at the 
> > 
> > hold 
> > 
> >>>>>>capacitors > >>>>after the VCO CV demux IC15 (a 4051) on 
> >>>>>
> >>>>>KLM-301 board.  These
> >>>>
> >>>>are
> >>>>
> >>>>>>>the
> >>>>>>>
> >>>>>>>>>>caps C25 - C32.
> >>>>>>>>>
> >>>>>>>>>Good luck,
> >>>>>>>>>
> >>>>>>>>>Johannes
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>gil_we wrote:
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>>I've been recovering this one, found in the flea market.
> >>>>
> >>>>Overall
> >>>>
> >>>>>>>it > >>>>>had about 8-9 different faults that I fixed, 
> >>>>>
> >>>>>leaving two > > problems.
> >>>>>
> >>>>>>>>>>>The first is a bad SSM2056 chip which I need to find. 
> > 
> > The
> > 
> >>>>second
> >>>>
> >>>>>>>i > >>>>>probably inherent in the discrete ciruit of the 
> >>>>>
> >>>>>second > > oscillator.
> >>>>>
> >>>>>>>>>>>Upon powering it up, that particular oscillator will 
> > 
> > be 
> > 
> >>>>>out of > > tune, > >>>>>till it gets to its max. internal 
> >>>>>temperature where the tuning > > of > >>>>>that VCO is geting 
> >>>>>more or less - stable.
> >>>>>
> >>>>>>>>>>All other oscillators are immediately in tune, no matter 
> >>
> >>what
> >>
> >>>>is
> >>>>
> >>>>>>>the > >>>>>temperatue inside the machine.
> >>>>>>>
> >>>>>>>>>>I, of course, tried to figure out what the bad component 
> >>
> >>is 
> >>
> >>>>>by >>>>>blowing with a straw on each and each of the 
> > 
> > suspected 
> > 
> >>>>>>compnents, but > >>>>>blowing on every component on the 
> >>
> >>circuit 
> >>
> >>>>>of that oscialltor > > which > >>>>>seems to be pitch 
> > 
> > related, 
> > 
> >>>>>seems to effect the pitch.
> >>>>>
> >>>>>>>>>>I also tried to switch transistors between the bad 
> >>>>>
> >>>>>oscillator > > and > >>>>>another (working one) but the 
> > 
> > problem 
> > 
> >>>>>persisted.
> >>>>>
> >>>>>>>>>>Does anyone have any other idea / direction ?
> >>>>>>>>>>
> >>>>>>>>>>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
> >>>>
> >>>>
> >>>>
> >>>>
> >>>
> >>>
> >>>
> >>>.sig
> >>>-Chromatest J. Pantsmaker
> >>>http://www.chromatest.net
> >>>
> >>
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
> > Yahoo! Groups Links
> > 
> > 
> > 
> >  
> > 
> > 
> > 
> >
>

Now I got the feeling the the multitransistor has gone defected... I 
let the machine work all night long, and when I check it out the 
dualtransistor is not hot at all ! It used to get very hot when I let 
it work for a few hours... could it just has gone defected ?
Any idea what voltages I should see on either of the legs ?  Thanks



--- In PolySix@yahoogroups.com, "gil_we" <gil_we@y...> wrote:
>
> Now I see what happened... I guess that was a big mistake using the 
> freeze spray on such a sensitive circuit.
> 
> The problem is that I already even readjusted VR3, VR4 and VR5... 
So 
> even if and when the bad componet gets to its natural state the 
synth 
> will be out of tune ! shouldn't have touched it from the start ...
> 
> Johannes, 
> 
> 1. can the dual transistor get back to its initial, natural state ? 
> Maybe if I let the machine work a few days (so the components 
> can "recover" from the freeze harm - maybe by warming up ?)
> 
> 2. Do VR4 (Antilog Freq.), VR3 (Antilog Width) and VR5 (Antilog 
> Offset) act like the VR6 (Hi Tune), VR7 (Mid Tune) and VR5 (Low 
> Tune) - on the Polysix new-version ? So basically if and when the 
> components are ok, I should be able to tune it the same way you 
tune 
> a Polysix ?
> 
> 3. Last question - should the TH1 heat sensor be located just over 
> the multitransistor in general ? it was leaning over the circuit 
> board when I check it out, just realized it is a sesnor...
> 
> Thanks very much, I SHOULD fix that one it's one of a monster 
> beautifully sounding instrument !
> 
> 
> 
> --- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...> 
> wrote:
> >
> > The "multileg component" probably is the dual transistor for the
> > antilog amplifier.  This is one of the most critical stages in 
terms
> > of note frequency.  It has an exponential transfer characteristic,
> > which means that a tiny variation at the input may cause a huge at
> > the output.  Applying a freeze spray definitely will have a large
> > effect on the tune of the instrument, but all voices are affected
> > equally, because the antilog conversion is applied to the multi-
> > plexed CV.
> > 
> > gil_we wrote:
> > > ooops... the multileg component is IC6, not R40
> > > 
> > > 
> > > --- In PolySix@yahoogroups.com, "gil_we" <gil_we@y...> wrote:
> > > 
> > >>Thanks guys !
> > >>
> > >>There was something strange going on.... After writing my 
> previous 
> > >>mail I ran over a few components with a "freeze" spray, among 
> them 
> > >>the transistors and caps area of both VCOs on the problematic 
> > >>oscillator and the R40 component (what looks like a mutli-leg 
> > >>transistor but I guess is a multi-resistor ?)
> > >>
> > >>Suddenly, two things happen (which still happen if I turn the 
> > > 
> > > machine 
> > > 
> > >>off for a few hours and back on... regardless internal 
> temperature):
> > >>
> > >>1. The bad oscillator is no more out of tune !
> > >>
> > >>2. The entire scale has changed - i.e the gap between each note 
> to 
> > >>the one that follows it is larger (there is more than one 
octave 
> > > 
> > > gap 
> > > 
> > >>between C4 and C5 for example)
> > >>
> > >>But that made me recall that when I got hte unit there was not 
> > > 
> > > tuning 
> > > 
> > >>issue at all, and the bad tuning problem on the second 
oscillator 
> > >>only started once I started servicing the machine)
> > >>
> > >>Strange huh ?
> > >>
> > >>Could it be R40 that is defective ? does that make sense ?
> > >>
> > >>Thanks again !
> > >>
> > >>
> > >>
> > >>
> > >>
> > >>--- In PolySix@yahoogroups.com, "Chromatest J. Pantsmaker" 
> > >><chromatest@g...> wrote:
> > >>
> > >>>
> > >>>
> > >>>replace them again?  Sometimes (and it will always bite you) 
you 
> > >>
> > >>put in a bunk part as a replacement.. then you spend all week 
> > > 
> > > looking 
> > > 
> > >>for something else, saying "it can't be X!  I replaced X"..
> > >>
> > >>>
> > >>>----- Original Message -----
> > >>>From: gil_we <gil_we@y...>
> > >>>To: PolySix@yahoogroups.com
> > >>>Subject: [PolySix] Re: Trident MKII - one oscillator is out of 
> > > 
> > > tune
> > > 
> > >>>Date: Tue, 06 Dec 2005 21:51:15 -0000
> > >>>
> > >>>
> > >>>>You know what ?... now I relaize I replaced IC8 and ICx11 as 
> > >>
> > >>well !
> > >>
> > >>>>Any other idea you can think of ?
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner 
> > >>
> > >><johau@g...>
> > >>
> > >>>>wrote:
> > >>>>
> > >>>>>If you already replaced Rx39/Cx10 then the only thing in 
> > > 
> > > common
> > > 
> > >>>>>for both VCOs in one voice is ICx11 (TL072).  THe value of 
> > > 
> > > Rx39
> > > 
> > >>>>>is not very critical unless it is very different to the 
> > > 
> > > nominal
> > > 
> > >>>>>value of 1k
> > >>>>>
> > >>>>> > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> > >>>>>No, I mean IC8, which is a 4051.  It is common to all 
voices; 
> > > 
> > > it
> > > 
> > >>>>>demultiplexes the CV for the VCOs
> > >>>>>
> > >>>>>Johannes
> > >>>>>
> > >>>>>
> > >>>>>gil_we wrote:
> > >>>>>
> > >>>>>>Thanks !
> > >>>>>>
> > >>>>>>>The Cx10 and Rx39 have been already replaced to no avail.
> > >>>>>>>By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> > >>>>>>>btw, I now see that I had to replace Rx36 with a slightly
> > >>>>
> > >>>>different
> > >>>>
> > >>>>>>value because even after the machine is warm enough, with 
> > > 
> > > the
> > > 
> > >>>>>>original value the related VCO still cannot get tuned with 
> > > 
> > > the
> > > 
> > >>>>other
> > >>>>
> > >>>>>>oscillators, not matter how you set the VCO tuning trimmers.
> > >>>>>>
> > >>>>>>>Thanks again.
> > >>>>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner
> > >>>>
> > >>>><johau@g...>
> > >>>>
> > >>>>>>wrote:
> > >>>>>>
> > >>>>>>>>Hi,
> > >>>>>>>
> > >>>>>>>The caps are Cx10 ... where x is the voice number. On the
> > >>>>
> > >>>>schematics
> > >>>>
> > >>>>>>>only voice #7 is drawn in detail, so you can see C710. 
> > > 
> > > Maybe 
> > > 
> > >>it
> > >>
> > >>>>is
> > >>>>
> > >>>>>>>not
> > >>>>>>>
> > >>>>>>>>the cap but the accompanying resistor (R739), or the 
> > > 
> > > demux 
> > > 
> > >>(IC8).
> > >>
> > >>>>>>>This is a great machine. Two really independant VCOs!
> > >>>>>>>
> > >>>>>>>Johannes
> > >>>>>>>
> > >>>>>>>
> > >>>>>>>gil_we wrote:
> > >>>>>>>
> > >>>>>>>
> > >>>>>>>>Thanks very much !
> > >>>>>>>>
> > >>>>>>>>The tuning is bad on both VCO1 and VCO2 of that 
oscillator 
> > >>
> > >>>>>(although > >>>it seems more extreme on VCO2).
> > >>>>>
> > >>>>>>>>I uploaded the schematics diagram for the VCO board to 
the 
> > >>>>>
> > >>>>>files >>>section - what would be the caps to check on that 
> > > 
> > > one ?
> > > 
> > >>>>>>>>Thanks again.
> > >>>>>>>>
> > >>>>>>>>
> > >>>>>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner > 
> 
> > >>>>>
> > >>>>><johau@g...> > >>>wrote:
> > >>>>>
> > >>>>>>>>
> > >>>>>>>>>Hi,
> > >>>>>>>>>
> > >>>>>>>>>I only have the schematics for the MK I; which I do not 
> > >>
> > >>know > > whether
> > >>
> > >>>>>>>>>>it is similar to the MK II. Which VCO has the problem? 
> > > 
> > > Is 
> > > 
> > >>it
> > >>
> > >>>>VCO-
> > >>>>
> > >>>>>>>1 or
> > >>>>>>>
> > >>>>>>>>>>VCO-2 or both? If it is both then have a look at the 
> > > 
> > > hold 
> > > 
> > >>>>>>capacitors > >>>>after the VCO CV demux IC15 (a 4051) on 
> > >>>>>
> > >>>>>KLM-301 board.  These
> > >>>>
> > >>>>are
> > >>>>
> > >>>>>>>the
> > >>>>>>>
> > >>>>>>>>>>caps C25 - C32.
> > >>>>>>>>>
> > >>>>>>>>>Good luck,
> > >>>>>>>>>
> > >>>>>>>>>Johannes
> > >>>>>>>>>
> > >>>>>>>>>
> > >>>>>>>>>gil_we wrote:
> > >>>>>>>>>
> > >>>>>>>>>
> > >>>>>>>>>
> > >>>>>>>>>>I've been recovering this one, found in the flea market.
> > >>>>
> > >>>>Overall
> > >>>>
> > >>>>>>>it > >>>>>had about 8-9 different faults that I fixed, 
> > >>>>>
> > >>>>>leaving two > > problems.
> > >>>>>
> > >>>>>>>>>>>The first is a bad SSM2056 chip which I need to find. 
> > > 
> > > The
> > > 
> > >>>>second
> > >>>>
> > >>>>>>>i > >>>>>probably inherent in the discrete ciruit of the 
> > >>>>>
> > >>>>>second > > oscillator.
> > >>>>>
> > >>>>>>>>>>>Upon powering it up, that particular oscillator will 
> > > 
> > > be 
> > > 
> > >>>>>out of > > tune, > >>>>>till it gets to its max. internal 
> > >>>>>temperature where the tuning > > of > >>>>>that VCO is 
geting 
> > >>>>>more or less - stable.
> > >>>>>
> > >>>>>>>>>>All other oscillators are immediately in tune, no 
matter 
> > >>
> > >>what
> > >>
> > >>>>is
> > >>>>
> > >>>>>>>the > >>>>>temperatue inside the machine.
> > >>>>>>>
> > >>>>>>>>>>I, of course, tried to figure out what the bad 
component 

> > >>
> > >>is 
> > >>
> > >>>>>by >>>>>blowing with a straw on each and each of the 
> > > 
> > > suspected 
> > > 
> > >>>>>>compnents, but > >>>>>blowing on every component on the 
> > >>
> > >>circuit 
> > >>
> > >>>>>of that oscialltor > > which > >>>>>seems to be pitch 
> > > 
> > > related, 
> > > 
> > >>>>>seems to effect the pitch.
> > >>>>>
> > >>>>>>>>>>I also tried to switch transistors between the bad 
> > >>>>>
> > >>>>>oscillator > > and > >>>>>another (working one) but the 
> > > 
> > > problem 
> > > 
> > >>>>>persisted.
> > >>>>>
> > >>>>>>>>>>Does anyone have any other idea / direction ?
> > >>>>>>>>>>
> > >>>>>>>>>>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
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>
> > >>>
> > >>>
> > >>>.sig
> > >>>-Chromatest J. Pantsmaker
> > >>>http://www.chromatest.net
> > >>>
> > >>
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
> > > Yahoo! Groups Links
> > > 
> > > 
> > > 
> > >  
> > > 
> > > 
> > > 
> > >
> >
>

Juhannes, back to the second VCO tuning problem,
are the caps you mentioned suppsed to be of special make or 
temperature resistant, ot does just about any polyester caps will do ?




--- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...> 
wrote:
>
> Hi,
> 
> The caps are Cx10 ... where x is the voice number. On the schematics
> only voice #7 is drawn in detail, so you can see C710. Maybe it is 
not
> the cap but the accompanying resistor (R739), or the demux (IC8).
> 
> This is a great machine. Two really independant VCOs!
> 
> Johannes
> 
> 
> gil_we wrote:
> > Thanks very much !
> > 
> > The tuning is bad on both VCO1 and VCO2 of that oscillator 
(although 
> > it seems more extreme on VCO2).
> > 
> > I uploaded the schematics diagram for the VCO board to the files 
> > section - what would be the caps to check on that one ?
> > 
> > Thanks again.
> > 
> > 
> > --- In PolySix@yahoogroups.com, Johannes Hausensteiner 
<johau@g...> 
> > wrote:
> > 
> >>Hi,
> >>
> >>I only have the schematics for the MK I; which I do not know 
whether
> >>it is similar to the MK II. Which VCO has the problem? Is it VCO-
1 or
> >>VCO-2 or both? If it is both then have a look at the hold 
capacitors 
> >>after the VCO CV demux IC15 (a 4051) on KLM-301 board.  These are 
the
> >>caps C25 - C32.
> >>
> >>Good luck,
> >>
> >>Johannes
> >>
> >>
> >>gil_we wrote:
> >>
> >>>I've been recovering this one, found in the flea market. Overall 
it 
> >>>had about 8-9 different faults that I fixed, leaving two 
problems.
> >>>
> >>>The first is a bad SSM2056 chip which I need to find. The second 
i 
> >>>probably inherent in the discrete ciruit of the second 
oscillator.
> >>>
> >>>Upon powering it up, that particular oscillator will be out of 
tune, 
> >>>till it gets to its max. internal temperature where the tuning 
of 
> >>>that VCO is geting more or less - stable.
> >>>
> >>>All other oscillators are immediately in tune, no matter what is 
the 
> >>>temperatue inside the machine.
> >>>
> >>>I, of course, tried to figure out what the bad component is by 
> >>>blowing with a straw on each and each of the suspected 
compnents, but 
> >>>blowing on every component on the circuit of that oscialltor 
which 
> >>>seems to be pitch related, seems to effect the pitch.
> >>>
> >>>I also tried to switch transistors between the bad oscillator 
and 

> >>>another (working one) but the problem persisted.
> >>>
> >>>Does anyone have any other idea / direction ?
> >>>
> >>>Thanks
> >>>
> >>>
> >>>
> >>>
> >>
> >> 
> >> 
> > 
> > 
> >
>

Problem solved !

It was wrong types of capacitors used for x08 , x09 and x10

Schematics says they are supposed to be polypropelene... used ceramic 
or polyester...

Got some high voltage polypropelene in and viola ! Tuning stability 
is back !

Thanks !!




--- In PolySix@yahoogroups.com, "gil_we" <gil_we@y...> wrote:
>
> Juhannes, back to the second VCO tuning problem,
> are the caps you mentioned suppsed to be of special make or 
> temperature resistant, ot does just about any polyester caps will 
do ?
> 
> 
> 
> 
> --- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...> 
> wrote:
> >
> > Hi,
> > 
> > The caps are Cx10 ... where x is the voice number. On the 
schematics
> > only voice #7 is drawn in detail, so you can see C710. Maybe it 
is 
> not
> > the cap but the accompanying resistor (R739), or the demux (IC8).
> > 
> > This is a great machine. Two really independant VCOs!
> > 
> > Johannes
> > 
> > 
> > gil_we wrote:
> > > Thanks very much !
> > > 
> > > The tuning is bad on both VCO1 and VCO2 of that oscillator 
> (although 
> > > it seems more extreme on VCO2).
> > > 
> > > I uploaded the schematics diagram for the VCO board to the 
files 
> > > section - what would be the caps to check on that one ?
> > > 
> > > Thanks again.
> > > 
> > > 
> > > --- In PolySix@yahoogroups.com, Johannes Hausensteiner 
> <johau@g...> 
> > > wrote:
> > > 
> > >>Hi,
> > >>
> > >>I only have the schematics for the MK I; which I do not know 
> whether
> > >>it is similar to the MK II. Which VCO has the problem? Is it 
VCO-
> 1 or
> > >>VCO-2 or both? If it is both then have a look at the hold 
> capacitors 
> > >>after the VCO CV demux IC15 (a 4051) on KLM-301 board.  These 
are 
> the
> > >>caps C25 - C32.
> > >>
> > >>Good luck,
> > >>
> > >>Johannes
> > >>
> > >>
> > >>gil_we wrote:
> > >>
> > >>>I've been recovering this one, found in the flea market. 
Overall 
> it 
> > >>>had about 8-9 different faults that I fixed, leaving two 
> problems.
> > >>>
> > >>>The first is a bad SSM2056 chip which I need to find. The 
second 
> i 
> > >>>probably inherent in the discrete ciruit of the second 
> oscillator.
> > >>>
> > >>>Upon powering it up, that particular oscillator will be out of 
> tune, 
> > >>>till it gets to its max. internal temperature where the tuning 
> of 
> > >>>that VCO is geting more or less - stable.
> > >>>
> > >>>All other oscillators are immediately in tune, no matter what 
is 

> the 
> > >>>temperatue inside the machine.
> > >>>
> > >>>I, of course, tried to figure out what the bad component is by 
> > >>>blowing with a straw on each and each of the suspected 
> compnents, but 
> > >>>blowing on every component on the circuit of that oscialltor 
> which 
> > >>>seems to be pitch related, seems to effect the pitch.
> > >>>
> > >>>I also tried to switch transistors between the bad oscillator 
> and 
> > >>>another (working one) but the problem persisted.
> > >>>
> > >>>Does anyone have any other idea / direction ?
> > >>>
> > >>>Thanks
> > >>>
> > >>>
> > >>>
> > >>>
> > >>
> > >> 
> > >> 
> > > 
> > > 
> > >
> >
>