Korg Mono/Poly

Hello,

This is my first post here. It seems a great yahoo Forum with knowledge base and I would like to thank all people here for sharing their help to others. That's really very rare to be found at that days.

Recently I bought a 2nd hand Monopoly, which had some issues.
I cleaned some key contacts which they were filthy and were not working during pressure and I also cleaned some pots internally with the appropriate alcohol which were not accurate and everything seems work fine except one thing:

Let's say:
1. Portamento Knob is at 0
2. VCO1, VCO2 and VC03 are almost tuned correctly


In mono or poly mode:
VCO4 comes "the portamenting way" from some note (not sure which) to almost 4 notes out of tune from the other VCOs.

For instance if I play a C, all other VCOs plays C, VCO4 comes with a portamento sound from some other note.. and stops tuned to F. When it stops to F, it can be detuned from it's know but it can only come one tone up or down, it cannot come to C.

Is this the same issue like http://launch.groups.yahoo.com/group/korg_mono-poly/message/598 ? or it is another issue ?

I opened the case, I noticed that I do not have the version of Monopoly which pictured here: http://fa.utfs.org/diy/korg_monopoly/monopoly_VCO_pcb.jpg in order to adjust the VC4.

I have this version: http://tinypic.com/r/141p7di/5 (you can use this photo in any site for repair info if needed), so I assume that the pcb KLM-354 is between the board and the front panel of Monopoly, correct ?

Could you help me if I need first to replace the possible defective HD14066BP or one relative (if this is the cause of the Portamento bug on VCO-4) and then to tune the VCO4 or I have to check/replace something else ?

The instrument had been repaired on 9/2007 but I am not aware what issue had then or if it was a proactive maintenance or any other issue.

Thank you very much for reading my issue

Hello

Am 08.03.2012 12:23, schrieb dir_marillion:

> Is this the same issue like
> http://launch.groups.yahoo.com/group/korg_mono-poly/message/598
> ?

I think the TL072 which does the portamento buffering for VCO4 might be
broken. It is IC10.

Florian

--
*http://fa.utfs.org/*

Hi Florian,
Thank you very much. Is this TL072 on the same board as the HD14066BP ? Does it have a similar or I can order it as TL072 ?
Do I have to tune all of the VCOs then ?

--- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Hello
>
> Am 08.03.2012 12:23, schrieb dir_marillion:
> > Is this the same issue like
> > http://launch.groups.yahoo.com/group/korg_mono-poly/message/598
> > ?
> I think the TL072 which does the portamento buffering for VCO4 might be
> broken. It is IC10.
>
> Florian
>
> --
> *http://fa.utfs.org/*
>

Am 08.03.2012 13:10, schrieb dir_marillion:

>
> Hi Florian,
> Thank you very much. Is this TL072 on the same board as the HD14066BP ? Does it have a similar or I can order it as TL072 ?
> Do I have to tune all of the VCOs then ?

The TL072 is a standard chip you will get it at any electronics shop
It is located on the VCO board close to Connector CN12

Florian

Hello. I have the same problem. If I leave th MP4 on for a while the VCO's and the portamento works allright. I would like to fix the problem though, so please tele me if it works for you if you try it out.
Thanks!
Jeppe

Am 08.03.2012 15:10, schrieb Jeppe Madsen:

> Hello. I have the same problem. If I leave th MP4 on for a while the
> VCO's and the portamento works allright. I would like to fix the problem
> though, so please tele me if it works for you if you try it out.
> Thanks!

Jeppe! dir_marillion related his request to your thread two years ago.
You never responded my suggestion. Did you ever try to replace the 4066?

Florian

No... Sorry I didn't respond. My mail went under and i couldn't post. So I requested access to the group only recently.

I never got around to replacing it because I would just let the MP sit with power on for a while and it would work fine. Call me lazy. :) And I couldn't risk breaking the MP4 because I was gigging a lot with it. But i'll get around to it. Just like I'll get around to modding it... some day.

But I really appreciate how helpfull you've been in this group Florian.

Jeppe

Hi Florian,

I bought 4x TL072CP chips, for a very low price.
I am not sure what is the CP at the end of the TL072.

*** Please confirm (if you know) that this can be used ***

Do you suggest to replace all the chips in all VCOs or only the onw on VCO4 ?

I will open my Monopoly tomorrow morning and I will let you know (I may be able to grab a couple of photos and post them somewhere, if needed, for future reference).

--- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Am 08.03.2012 13:10, schrieb dir_marillion:
> >
> > Hi Florian,
> > Thank you very much. Is this TL072 on the same board as the HD14066BP ? Does it have a similar or I can order it as TL072 ?
> > Do I have to tune all of the VCOs then ?
> The TL072 is a standard chip you will get it at any electronics shop
> It is located on the VCO board close to Connector CN12
>
> Florian
>

Hello,

TL072 ist _the_ standard chip. All your music gear is using those, as
TL071/72/74 (1, 2 or four OpAmps). There is nothing special about them.
They cost only some cent (Euro and Dollar).

You should replace only the IC10 (the one for VCO4). Please be careful
when unsoldering! Don't rip the traces of the pcb.

Florian

dir_marillion wrote:

> Hi Florian,
>
> I bought 4x TL072CP chips, for a very low price.
> I am not sure what is the CP at the end of the TL072.
>
> *** Please confirm (if you know) that this can be used ***
>
> Do you suggest to replace all the chips in all VCOs or only the onw on VCO4 ?
>
> I will open my Monopoly tomorrow morning and I will let you know (I may be able to grab a couple of photos and post them somewhere, if needed, for future reference).

Hi

Florian Anwander wrote:

> [everything Alan has written already...]

Sorry, I had not seen, that Alan wrote everything already. I dod not
want to double it.

Florian

Hi,
I did not understand if Alan meant that I can use the TL072CP or not or I have to buy another chips which are only TL072 and not CP.

I will open the Mono/Poly tomorrow and will see what I can do. Then I will let you know. If it is in a very complicated place I will not do it. If I am lucky enough and the chip is already plugged to a stand, I will replace it immediately :-)

Really, where is the pcb KLM-354 to my revision board ? (check the picture I linked on my first post).

Alan and Florian, I really appreciate your effort to help me.

--- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Hi
>
> Florian Anwander wrote:
> > [everything Alan has written already...]
> Sorry, I had not seen, that Alan wrote everything already. I dod not
> want to double it.
>
> Florian
>

Sorry to correct my previous post.
I mean where is the board KLM-398 to my board ?
According the picture I sent in my first post, it is not where it should be.

--- In korg_mono-poly@yahoogroups.com, "dir_marillion" <dir_marillion@...> wrote:
>
> Hi,
> I did not understand if Alan meant that I can use the TL072CP or not or I have to buy another chips which are only TL072 and not CP.
>
> I will open the Mono/Poly tomorrow and will see what I can do. Then I will let you know. If it is in a very complicated place I will not do it. If I am lucky enough and the chip is already plugged to a stand, I will replace it immediately :-)
>
> Really, where is the pcb KLM-354 to my revision board ? (check the picture I linked on my first post).
>
> Alan and Florian, I really appreciate your effort to help me.
>
> --- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@> wrote:
> >
> > Hi
> >
> > Florian Anwander wrote:
> > > [everything Alan has written already...]
> > Sorry, I had not seen, that Alan wrote everything already. I dod not
> > want to double it.
> >
> > Florian
> >
>

Hi Alan,
Thank you very much for the info. I will check it tomorrow and will let you know.

The internal photo from my Mono/Poly is this: http://tinypic.com/r/141p7di/5 and there is not this brown pcb as you say. That's why I am asking you. I assume it is located somewhere between KLM-398 and the upper case of the instrument...

Thanks

--- In korg_mono-poly@yahoogroups.com, Alan Dicker <alanmdicker@...> wrote:
>
> Yes you can use TL072CP don't worry about the CP the number is right.
> Not sure what you mean by where is KLM-398.  Its right here in your picture.  The small brown board wit the 4 VRs on it.  You want to be looking at the board behind that the larger KLM-354 which is where IC10 that Florian mentioned is located.  You will need to remove the knob tops and nuts from the front panel and unscrew KLM-398 to see the other side of it where all the components are located.  You should then be able to locate and remove IC-10.  I very much doubt it is already in a socket unless is has been repairs before.  Usually these very common op-amps aren't socketed as standard but things like the SSM 2033 VOC chips usually are.  I find a good thick solder wick to be my preferred method of de-soldering components.  If you are unsure on your solder skills then either get a professional to do it or find some old electronic junk boards and practise removing and re-soldering components from those until you have the skill to do it well.
>
> Alan
>
>
>
> ________________________________
> From: dir_marillion <dir_marillion@...>
> To: korg_mono-poly@yahoogroups.com
> Sent: Thursday, 8 March 2012, 22:08
> Subject: [korg_mono-poly] Re: Monopoly VCO-4 prtamento/detuning issue
>
>
>  
> Sorry to correct my previous post.
> I mean where is the board KLM-398 to my board ?
> According the picture I sent in my first post, it is not where it should be.
>
> --- In korg_mono-poly@yahoogroups.com, "dir_marillion" <dir_marillion@> wrote:
> >
> > Hi,
> > I did not understand if Alan meant that I can use the TL072CP or not or I have to buy another chips which are only TL072 and not CP.
> >
> > I will open the Mono/Poly tomorrow and will see what I can do. Then I will let you know. If it is in a very complicated place I will not do it. If I am lucky enough and the chip is already plugged to a stand, I will replace it immediately :-)
> >
> > Really, where is the pcb KLM-354 to my revision board ? (check the picture I linked on my first post).
> >
> > Alan and Florian, I really appreciate your effort to help me.
> >
> > --- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@> wrote:
> > >
> > > Hi
> > >
> > > Florian Anwander wrote:
> > > > [everything Alan has written already...]
> > > Sorry, I had not seen, that Alan wrote everything already. I dod not
> > > want to double it.
> > >
> > > Florian
> > >
> >
>

Hello

the old version of the MonoPoly did not have the KLM398. Also I don't
understand what for you are looking at the 398. You have to change the
IC10 on KLM354.

Florian

dir_marillion wrote:

> Sorry to correct my previous post.
> I mean where is the board KLM-398 to my board ?
> According the picture I sent in my first post, it is not where it should be.
>
> --- In korg_mono-poly@yahoogroups.com, "dir_marillion"<dir_marillion@...> wrote:
>>
>> Hi,
>> I did not understand if Alan meant that I can use the TL072CP or not or I have to buy another chips which are only TL072 and not CP.
>>
>> I will open the Mono/Poly tomorrow and will see what I can do. Then I will let you know. If it is in a very complicated place I will not do it. If I am lucky enough and the chip is already plugged to a stand, I will replace it immediately :-)
>>
>> Really, where is the pcb KLM-354 to my revision board ? (check the picture I linked on my first post).
>>
>> Alan and Florian, I really appreciate your effort to help me.
>>
>> --- In korg_mono-poly@yahoogroups.com, Florian Anwander<fanwander@> wrote:
>>>
>>> Hi
>>>
>>> Florian Anwander wrote:
>>>> [everything Alan has written already...]
>>> Sorry, I had not seen, that Alan wrote everything already. I dod not
>>> want to double it.
>>>
>>> Florian
>>>
>>
>
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>

Hi,

Ok, I understood that I have the older revision of Monopoly, that;s why I do not have the KLM398.

Today I opened the case as promised, with care.
You can see the picture: http://tinypic.com/r/v3oq4i/5

Of course I can only replace the 4066 chips which both are socketed.
The second one is under the cable.

Is the TL072CP under the capacitors (inside the circle) ?

Portamento works perfect to the other VCOs and can be adjusted from 1 to 10. Only in VCO4 it is always on and cannot be adjusted.

Do you suggest to replace the TL072 or I may have a damaged 4006 ?

Second question. As VC04 is also detuned about 4 notes and I do not have the KLM398, which are the switches for the 4rth VCO that I have to tune ? I show two white circle tuners under the fourth VCO (check my uploaded picture).

--- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Hello
>
> the old version of the MonoPoly did not have the KLM398. Also I don't
> understand what for you are looking at the 398. You have to change the
> IC10 on KLM354.
>
> Florian
>
> dir_marillion wrote:
> > Sorry to correct my previous post.
> > I mean where is the board KLM-398 to my board ?
> > According the picture I sent in my first post, it is not where it should be.
> >
> > --- In korg_mono-poly@yahoogroups.com, "dir_marillion"<dir_marillion@> wrote:
> >>
> >> Hi,
> >> I did not understand if Alan meant that I can use the TL072CP or not or I have to buy another chips which are only TL072 and not CP.
> >>
> >> I will open the Mono/Poly tomorrow and will see what I can do. Then I will let you know. If it is in a very complicated place I will not do it. If I am lucky enough and the chip is already plugged to a stand, I will replace it immediately :-)
> >>
> >> Really, where is the pcb KLM-354 to my revision board ? (check the picture I linked on my first post).
> >>
> >> Alan and Florian, I really appreciate your effort to help me.
> >>
> >> --- In korg_mono-poly@yahoogroups.com, Florian Anwander<fanwander@> wrote:
> >>>
> >>> Hi
> >>>
> >>> Florian Anwander wrote:
> >>>> [everything Alan has written already...]
> >>> Sorry, I had not seen, that Alan wrote everything already. I dod not
> >>> want to double it.
> >>>
> >>> Florian
> >>>
> >>
> >
> >
> >
> >
> > ------------------------------------
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
>

Hello

Am 09.03.2012 14:24, schrieb dir_marillion:

> Is the TL072CP under the capacitors (inside the circle) ?

Yes. There are two, but the one which affects VCO4 is under the second
bentover capacitor (counted from the bottom of the circle).

> Do you suggest to replace the TL072 or I may have a damaged 4006 ?

There is a basic principle of search for faults: never change two things
in the same step.

So the order of steps should be:
* Replace IC10 (TL072)
* Check the portamento of voice 4
* If it does not work: check the fourfolded portamento potentiometer, in
case of doubt shortcut in each layer of the potentiometer the two outer
contacts
* Check the portamento of voice 4
* If it does not work: insert a cable into the portamento socket (this
switches the 4066).
* Check the portamento of voice 4

> Second question. As VC04 is also detuned about 4 notes and I do not
> have the KLM398, which are the switches for the 4rth VCO that I have
> to tune ? I show two white circle tuners under the fourth VCO (check
> my uploaded picture).

You don't need KLM398, but only KLM354. I described the tuning procedure
in detail at http://fa.utfs.org/diy/korg_monopoly/vco_adjustment.html
I would NOT do the full procedure, but simply try to change the offset
with VR402
See
http://fa.utfs.org/diy/korg_monopoly/mp_16_klm_354_layout_TRIMMERS.jpg
the most left light green marking at the bottom named with "tune offset"

Florian

Hi Florian,
Your information is valuable !!!!!!!!

Thank you very very much.

I will follow your steps tomorrow morning, as I think you have almost explained me everything. I will also tune the VCO4 as you described, (the simple way to change the offset with VR402).

--- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Hello
>
> Am 09.03.2012 14:24, schrieb dir_marillion:
> > Is the TL072CP under the capacitors (inside the circle) ?
> Yes. There are two, but the one which affects VCO4 is under the second
> bentover capacitor (counted from the bottom of the circle).
>
>
> > Do you suggest to replace the TL072 or I may have a damaged 4006 ?
> There is a basic principle of search for faults: never change two things
> in the same step.
>
> So the order of steps should be:
> * Replace IC10 (TL072)
> * Check the portamento of voice 4
> * If it does not work: check the fourfolded portamento potentiometer, in
> case of doubt shortcut in each layer of the potentiometer the two outer
> contacts
> * Check the portamento of voice 4
> * If it does not work: insert a cable into the portamento socket (this
> switches the 4066).
> * Check the portamento of voice 4
>
>
>
> > Second question. As VC04 is also detuned about 4 notes and I do not
> > have the KLM398, which are the switches for the 4rth VCO that I have
> > to tune ? I show two white circle tuners under the fourth VCO (check
> > my uploaded picture).
> You don't need KLM398, but only KLM354. I described the tuning procedure
> in detail at http://fa.utfs.org/diy/korg_monopoly/vco_adjustment.html
> I would NOT do the full procedure, but simply try to change the offset
> with VR402
> See
> http://fa.utfs.org/diy/korg_monopoly/mp_16_klm_354_layout_TRIMMERS.jpg
> the most left light green marking at the bottom named with "tune offset"
>
> Florian
>

Hi,
Today I reopened the case and boards but I couldn't touch the TL chips. I am afraid that my skills are not too good to proceed unsolder it, without causing any damage.

The only I could do was to replace the both 4066 chips (just in case) which were sockedted and then to tune the VCO4 with the method you suggested.

The 4066 chips did not solve the issue with the portamento on VCO4, but the VCO4 tuned perfect, so now all the VCOs are perfectly tuned.

During the procedure, I checked all the Portamento pot lines, with a polymeter and they work.

So, in order to solve the issue with the Portamento on VCO4, I have to take it and go to the electronic shop, to replace this chip which is located under the capacitors (extra work has to be done).

Finally, I noticed that when I turn on my Monopoly, some times (not all, a random note is playing without any key pressure. I have to tell you that about 2 weeks ago, I opened the keyboard and replaced some rubbers with new ones and cleaned the others with a soft alcohol.
Strange ?

Thanks

--- In korg_mono-poly@yahoogroups.com, "dir_marillion" <dir_marillion@...> wrote:
>
> Hi Florian,
> Your information is valuable !!!!!!!!
>
> Thank you very very much.
>
> I will follow your steps tomorrow morning, as I think you have almost explained me everything. I will also tune the VCO4 as you described, (the simple way to change the offset with VR402).
>
> --- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@> wrote:
> >
> > Hello
> >
> > Am 09.03.2012 14:24, schrieb dir_marillion:
> > > Is the TL072CP under the capacitors (inside the circle) ?
> > Yes. There are two, but the one which affects VCO4 is under the second
> > bentover capacitor (counted from the bottom of the circle).
> >
> >
> > > Do you suggest to replace the TL072 or I may have a damaged 4006 ?
> > There is a basic principle of search for faults: never change two things
> > in the same step.
> >
> > So the order of steps should be:
> > * Replace IC10 (TL072)
> > * Check the portamento of voice 4
> > * If it does not work: check the fourfolded portamento potentiometer, in
> > case of doubt shortcut in each layer of the potentiometer the two outer
> > contacts
> > * Check the portamento of voice 4
> > * If it does not work: insert a cable into the portamento socket (this
> > switches the 4066).
> > * Check the portamento of voice 4
> >
> >
> >
> > > Second question. As VC04 is also detuned about 4 notes and I do not
> > > have the KLM398, which are the switches for the 4rth VCO that I have
> > > to tune ? I show two white circle tuners under the fourth VCO (check
> > > my uploaded picture).
> > You don't need KLM398, but only KLM354. I described the tuning procedure
> > in detail at http://fa.utfs.org/diy/korg_monopoly/vco_adjustment.html
> > I would NOT do the full procedure, but simply try to change the offset
> > with VR402
> > See
> > http://fa.utfs.org/diy/korg_monopoly/mp_16_klm_354_layout_TRIMMERS.jpg
> > the most left light green marking at the bottom named with "tune offset"
> >
> > Florian
> >
>

Hello

> So, in order to solve the issue with the Portamento on VCO4, I have
> to take it and go to the electronic shop, to replace this chip which
> is located under the capacitors (extra work has to be done).

Some question come to my mind now (I might have asked them before):
How does the portamento for VCO4 behave if you put the Synth to Unisono
mode?
Does the portamento happen also with switching the octave switch of VCO4?
Does C411 look different from C311,C211,and C111?
Can you measure the voltage on the KLM354 at Connector 12 pin4 and then
play octave jumps on the keyboard.
And then measure the voltage at the connection of R502 and IC10, while
making octave jumps.

My suspicion is that the previous owner modified the behaviour of VCO4
by intention. To my opinion this is confirmed by the fact, that the VCO4
was detuned to exactly 4 notes above (which can make sense for X-Mod
sounds). So maybe we should not look for a faulty part, but for signs of
modofications.

> Finally, I noticed that when I turn on my Monopoly, some times (not
> all, a random note is playing without any key pressure. I have to
> tell you that about 2 weeks ago, I opened the keyboard and replaced
> some rubbers with new ones and cleaned the others with a soft
> alcohol. Strange ?

This might happen, if the spring of a key is not right in place and the
key touches the button.


Florian

>Some question come to my mind now (I might have asked them before):
>How does the portamento for VCO4 behave if you put the Synth to >Unisono mode?

Only for VCO4: In all mono modes, Chord and Unison, portamento is set to 0:

pressing C: no portamento
pressing C again after few seconds: no portamento
pressing C again after few seconds: no portamento
pressing E: portamento appears
pressing E: no portamento
pressing C again after few seconds: no portamento
pressing C again after few seconds: no portamento
pressing G: portamento appears
pressing G: no portamento

Only for VCO4: In all mono modes, Chord and Unison, portamento is set to MAX:

Same behavior as above

>Does the portamento happen also with switching the octave switch of >VCO4?

It has exactly the same behavior at all positions of octave and waveform switches, whatever is selected from X-MOD, S&X or SYNC switch.
If there is a combination that I should check, such as for instance SYNC on, Unison Mono, Portamento at full etc… please let me know.

Currently I have closed the case of Monopoly so I cannot answer on your following questions:

a. Does C411 look different from C311,C211,and C111?
b. Can you measure the voltage on the KLM354 at Connector 12 pin4 and then play octave jumps on the keyboard.
c. And then measure the voltage at the connection of R502 and IC10, while making octave jumps.

>My suspicion is that the previous owner modified the behavior of >VCO4 by intention. To my opinion this is confirmed by the fact, that >the VCO4 was detuned to exactly 4 notes above (which can make sense >for X-Mod sounds). So maybe we should not look for a faulty part, >but for signs of modifications.

Yes, you are right; it is exactly as you said.

Please download the following file and check it's pictures, when it was open, so you may be able to recognize the possible modification.

This is the link with the ZIP file:

http://www.2shared.com/fadmin/26610218/4b21bac3/monopoly.zip.html

Then please let me know what else I should check.

Thank you

--- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Hello
>
> > So, in order to solve the issue with the Portamento on VCO4, I have
> > to take it and go to the electronic shop, to replace this chip which
> > is located under the capacitors (extra work has to be done).
> Some question come to my mind now (I might have asked them before):
> How does the portamento for VCO4 behave if you put the Synth to Unisono
> mode?
> Does the portamento happen also with switching the octave switch of VCO4?
> Does C411 look different from C311,C211,and C111?
> Can you measure the voltage on the KLM354 at Connector 12 pin4 and then
> play octave jumps on the keyboard.
> And then measure the voltage at the connection of R502 and IC10, while
> making octave jumps.
>
> My suspicion is that the previous owner modified the behaviour of VCO4
> by intention. To my opinion this is confirmed by the fact, that the VCO4
> was detuned to exactly 4 notes above (which can make sense for X-Mod
> sounds). So maybe we should not look for a faulty part, but for signs of
> modofications.
>
> > Finally, I noticed that when I turn on my Monopoly, some times (not
> > all, a random note is playing without any key pressure. I have to
> > tell you that about 2 weeks ago, I opened the keyboard and replaced
> > some rubbers with new ones and cleaned the others with a soft
> > alcohol. Strange ?
> This might happen, if the spring of a key is not right in place and the
> key touches the button.
>
>
> Florian
>

Hello

> Only for VCO4: In all mono modes, Chord and Unison, portamento is set to 0:
>
> pressing C: no portamento
> pressing C again after few seconds: no portamento
> pressing C again after few seconds: no portamento
> pressing E: portamento appears
> pressing E: no portamento
> pressing C again after few seconds: no portamento
> pressing C again after few seconds: no portamento
> pressing G: portamento appears
> pressing G: no portamento

Repeating a note never will produce portamento. Portamento slows down
note changes. Very interesting in this listing is that there is no
portamento when you jump from E back to C. Could you please play the
following:

C
E
G
B
G
E
C

is there alway portamento or only when the notes get higher?

>> Does the portamento happen also with switching the octave switch of>VCO4?
> It has exactly the same behavior at all positions of octave

You misunderstood. I meant: press and hold C and while holding the note
switch the footage setting 16" > 8" > 4" > 2" > 4" > 8" > 16" of the
VCO4. When you are back at 16" then release the key. Is there a
portamento caused by switching the octaves?

> Yes, you are right; it is exactly as you said.
> http://www.2shared.com/fadmin/26610218/4b21bac3/monopoly.zip.html
>
> Then please let me know what else I should check.

Aaaah! Things become clearer. I have to track the things in reverse. I
will come back later.

Florian

> Repeating a note never will produce portamento. Portamento slows >down note changes. Very interesting in this listing is that there is no portamento when you jump from E back to C. Could you please play >the following:
>
> C
> E
> G
> B
> G
> E
> C
>
> is there alway portamento or only when the notes get higher?

There is always a portamento to all directions, when portamento pot is set to 0 and when it is set to max.

> press and hold C and while holding the note switch the footage >setting 16" > 8" > 4" > 2" > 4" > 8" > 16" > of the VCO4. When you >are back at 16" then release the key. Is >there a portamento caused > by switching the octaves?

Portamento Pot is ON/OFF same behavior: it stays on
I did the sequence slower, fast and very fast and portamento is there.

Thank you

Hello

>> press and hold C and while holding the note switch the
>> footage>setting 16"> 8"> 4"> 2"> 4"> 8"> 16"> of the VCO4.
>> When you>are back at 16" then release the key. Is there a
>> portamento caused by switching the octaves?
> Portamento Pot is ON/OFF same behavior: it stays on I did the
> sequence slower, fast and very fast and portamento is there.

AAARRRGH!!!! You are mixing up things. Do not use a sequencer!!!! Stay
with one thing if you try to track down a failure. Never change two
variables at the same time!!!

Please do only this:
* Don't connect anything else to the Monopoly but Audio out to your
monitoring! No CV not gate nothing. Only Audio! Or use the headphone.
* Switch on the Monopoly and wait for 15 Minutes
* Do not play any note.
* After 15 Minutes press Unisono
* Do all settings on the synth like shown in
http://fa.utfs.org/diy/korg_monopoly/mp_20_adjustment_1.gif with
exception that you turn up VCO4 to 10 (instead of VCO1 in the picture)
* Press Hold
* Press C-Key: You should hear VCO4 play a steady tone.
* Do NOT play any other key while this procedure!!!
* Switch the octave setting of VCO4 to 8" then to 4", then back to 8"
and back to 16".

Do you hear portamento when switching the octave as described in the
last step?

Florian

Florian,

I did not use a sequencer. I meant I followed the sequence from 16 to 8 then to 4 then to 2... etc

Step 1:
I turned on the Monopoly, meanwhile I am writing this message.

Step 2:
The Knobs are ready like in http://fa.utfs.org/diy/korg_monopoly/mp_20_adjustment_1.gif VCO4=max, VCO1=0

Step 3:
Pressing HOLD to ON

Step 4:
Pressing C Key and release it.

Step 5:

Too silent sound so no difference when I switch the octave.
Pressing HOLD to OFF and now I can listen a little bit higher.
Maybe if this is another issue, but I am using the HOLD very often without any issues to other sounds.

Pressing C Key and do not release it this time (emulating the HOLD is pressed for some seconds).

Switching the Octave Setting from 16 to 8 then 4 and then back to 8, no Portamento during back to 8 (this is sure), but I cannot ensure if between the stages, I heard portamento because I had to switch fast until the sound finish.

I raise the decay and release to 6. Now the sound is clean and traveling enough but Portamento is not yet clear if it working on VCO4 when switching octaves. I can give a 75% that it remains ON at first stage from 16 to 8 and then dies somewhere between 8 and 4.

Please note that when I tuned the Monopoly, earlier today, I left decay, sustain and release at 6 and not on 0 in order to listen during tuning.

Should I turn the knobs to another settings to check from there if portamento remains ?

--- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Hello
>
> >> press and hold C and while holding the note switch the
> >> footage>setting 16"> 8"> 4"> 2"> 4"> 8"> 16"> of the VCO4.
> >> When you>are back at 16" then release the key. Is there a
> >> portamento caused by switching the octaves?
> > Portamento Pot is ON/OFF same behavior: it stays on I did the
> > sequence slower, fast and very fast and portamento is there.
>
>
> AAARRRGH!!!! You are mixing up things. Do not use a sequencer!!!! Stay
> with one thing if you try to track down a failure. Never change two
> variables at the same time!!!
>
> Please do only this:
> * Don't connect anything else to the Monopoly but Audio out to your
> monitoring! No CV not gate nothing. Only Audio! Or use the headphone.
> * Switch on the Monopoly and wait for 15 Minutes
> * Do not play any note.
> * After 15 Minutes press Unisono
> * Do all settings on the synth like shown in
> http://fa.utfs.org/diy/korg_monopoly/mp_20_adjustment_1.gif with
> exception that you turn up VCO4 to 10 (instead of VCO1 in the picture)
> * Press Hold
> * Press C-Key: You should hear VCO4 play a steady tone.
> * Do NOT play any other key while this procedure!!!
> * Switch the octave setting of VCO4 to 8" then to 4", then back to 8"
> and back to 16".
>
> Do you hear portamento when switching the octave as described in the
> last step?
>
> Florian
>

Hi

>> Yes, you are right; it is exactly as you said.
>> http://www.2shared.com/fadmin/26610218/4b21bac3/monopoly.zip.html
> Aaaah! Things become clearer. I have to track the things in reverse. I
> will come back later.

ok, I had a look at that:

Both groups of additional parts appearently are NOT modifications, but
they seem to be the standard wiring of the very first series. (in my
MonoPoly the same connections exists, but they are achieved as traces on
the pcb!)

The one on the VCF board is the the circuit around Q10, R85, R86, D7,
and C27.
The one on the bender board is the regular wiring of the Arpeggiator
Off/On/Latch switch.

The unused connector on the VCO board is appearently only a kind of
testsocket.


My most likely suspect is the portamento potentiometer itself. You wrote:

> During the procedure, I checked all the Portamento pot lines, with
> a polymeter and they work.

If you measure the lines, then you won't recognize if the slider of the
potentiometer itself is broken. Did you try to shortcut the portamento
potentiometer for vco4?

Florian

Hi,

Thank you for your time and effort to do something like that.

> The unused connector on the VCO board is appearently only a kind of
> testsocket.

I thought it was a relative midi connector which never implemented :-)

Now, about the Portamento Pot, I just checked that the lines are not cut. Without having the appropriate knowledge to read the schematics of the Monopoly, I tested it with just one thought:

While the pot is set to 0, the Portamento must be 0 to all VCOs unless it has four lines that each one goes to each VCO and in VCO4 case one line is cut so it is always on.

This was my thought for checking it.

Can you explain me a little how this pot works and what should I do to test and/or fix it ? Which is the line for VCO4 to shortcut and how can do this ? Does it contain graphite like the sliders on JX3p ?

Thanks

--- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Hi
>
> >> Yes, you are right; it is exactly as you said.
> >> http://www.2shared.com/fadmin/26610218/4b21bac3/monopoly.zip.html
> > Aaaah! Things become clearer. I have to track the things in reverse. I
> > will come back later.
> ok, I had a look at that:
>
> Both groups of additional parts appearently are NOT modifications, but
> they seem to be the standard wiring of the very first series. (in my
> MonoPoly the same connections exists, but they are achieved as traces on
> the pcb!)
>
> The one on the VCF board is the the circuit around Q10, R85, R86, D7,
> and C27.
> The one on the bender board is the regular wiring of the Arpeggiator
> Off/On/Latch switch.
>
> The unused connector on the VCO board is appearently only a kind of
> testsocket.
>
>
> My most likely suspect is the portamento potentiometer itself. You wrote:
> > During the procedure, I checked all the Portamento pot lines, with
> > a polymeter and they work.
> If you measure the lines, then you won't recognize if the slider of the
> potentiometer itself is broken. Did you try to shortcut the portamento
> potentiometer for vco4?
>
> Florian
>

Hi

> I raise the decay and release to 6. Now the sound is clean and
> traveling enough but Portamento is not yet clear if it working on
> VCO4 when switching octaves. I can give a 75% that it remains ON at
> first stage from 16 to 8 and then dies somewhere between 8 and 4.

Sustain for VCA must be to maximum (see the "10" in the graphic
http://fa.utfs.org/diy/korg_monopoly/mp_20_adjustment_1.gif)

Florian

Yes, I didn't changed the attack and the sustain.

--- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Hi
>
> > I raise the decay and release to 6. Now the sound is clean and
> > traveling enough but Portamento is not yet clear if it working on
> > VCO4 when switching octaves. I can give a 75% that it remains ON at
> > first stage from 16 to 8 and then dies somewhere between 8 and 4.
> Sustain for VCA must be to maximum (see the "10" in the graphic
> http://fa.utfs.org/diy/korg_monopoly/mp_20_adjustment_1.gif)
>
> Florian
>

Hi

> Can you explain me a little how this pot works and what should I do
> to test and/or fix it ?

The working principle of the portamento circuit is very simple. There is
an capacitor between ground and the control voltage line from the
keyboard for the VCO pitch. If the keyboard control voltage changes,
then its power will first be used to load the capacitor. This will take
some time. So the voltage change will not be immediate, but will
increase slowly. This causes at the VCO what we call portamento.
(The same happens if the voltage drops. Then the unloading will take
some time).

As said, loading or unloading the capacitor always takes a little time,
but if the CV comes with enough current (if the power is high enough
(remember: power = voltage x current), then the loading or unloading of
the capacitor is that fast, that our ear does not recognize it.

The portamento potentiometer now simply acts as a variable resistor (so
called rheostat) which is inserted in the CV-line before the capacitor.
If the poti is turned fully counterclockwise then the resulting resistor
is zero -> the capacitor will be loaded that fast, that we do not
recognize it.

If the poti now gets turned clockwise, the resulting resistor is
increased -> the increased resistor means less current runs into the
capacitor -> the capacitor will be loaded slowlier -> the pitch changes
slowlier -> portamento.

> Which is the line for VCO4 to shortcut and
> how can do this ?

I cannot tell you exactly which layer of this four layer potentiometer
is the one for the VCO4, but I found an article in the web, which
describes the principle of our problem quite good


Have a look at http://www.allaboutcircuits.com/vol_6/chpt_3/7.html

in the picture
http://sub.allaboutcircuits.com/images/05151.png
http://sub.allaboutcircuits.com/images/05150.png
you have to think the battery as the keyboard CV and the motor as the
capacitor. That is how the portamento potentiometer is wired.




The picture
http://sub.allaboutcircuits.com/images/05152.png
describes, what might be broken in your portamento potentiometer.

If you connect both the outer connectors of the potentiometer with each
other, then it is like the potentiometers resistance would not be set to
zero.

> Does it contain graphite like the sliders on JX3p
> ?

Yes. All potentiometers work like that, but you can't repair it with an
graphite spray!

Btw: it does not have to be the potentiometer itself. It could be that
the corresponding solder joint is corrupted.

Florian

Hi, I understood.

> Btw: it does not have to be the potentiometer itself. It could be >that the corresponding solder joint is corrupted.

I just re-opened the synth and checked all lines of the pot which correspond to the solder joints to the motherboard. No corruptions found. Will recheck.

The Synth is disconnected from power outlet and I am checking only if the lines are ok.

Of course I have not idea which line is for VCO4 and it seems that schematics do not show this detail...

--- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Hi
>
> > Can you explain me a little how this pot works and what should I do
> > to test and/or fix it ?
> The working principle of the portamento circuit is very simple. There is
> an capacitor between ground and the control voltage line from the
> keyboard for the VCO pitch. If the keyboard control voltage changes,
> then its power will first be used to load the capacitor. This will take
> some time. So the voltage change will not be immediate, but will
> increase slowly. This causes at the VCO what we call portamento.
> (The same happens if the voltage drops. Then the unloading will take
> some time).
>
> As said, loading or unloading the capacitor always takes a little time,
> but if the CV comes with enough current (if the power is high enough
> (remember: power = voltage x current), then the loading or unloading of
> the capacitor is that fast, that our ear does not recognize it.
>
> The portamento potentiometer now simply acts as a variable resistor (so
> called rheostat) which is inserted in the CV-line before the capacitor.
> If the poti is turned fully counterclockwise then the resulting resistor
> is zero -> the capacitor will be loaded that fast, that we do not
> recognize it.
>
> If the poti now gets turned clockwise, the resulting resistor is
> increased -> the increased resistor means less current runs into the
> capacitor -> the capacitor will be loaded slowlier -> the pitch changes
> slowlier -> portamento.
>
>
>
> > Which is the line for VCO4 to shortcut and
> > how can do this ?
>
> I cannot tell you exactly which layer of this four layer potentiometer
> is the one for the VCO4, but I found an article in the web, which
> describes the principle of our problem quite good
>
>
> Have a look at http://www.allaboutcircuits.com/vol_6/chpt_3/7.html
>
> in the picture
> http://sub.allaboutcircuits.com/images/05151.png
> http://sub.allaboutcircuits.com/images/05150.png
> you have to think the battery as the keyboard CV and the motor as the
> capacitor. That is how the portamento potentiometer is wired.
>
>
>
>
> The picture
> http://sub.allaboutcircuits.com/images/05152.png
> describes, what might be broken in your portamento potentiometer.
>
> If you connect both the outer connectors of the potentiometer with each
> other, then it is like the potentiometers resistance would not be set to
> zero.
>
>
>
>
>
> > Does it contain graphite like the sliders on JX3p
> > ?
> Yes. All potentiometers work like that, but you can't repair it with an
> graphite spray!
>
> Btw: it does not have to be the potentiometer itself. It could be that
> the corresponding solder joint is corrupted.
>
> Florian
>

Check this photo: http://tinypic.com/r/34sfsb9/5

I have enclosed which solder joint on Portamento pot corresponds with what. There are four pairs and I assume that there are both lines for every VCO.

--- In korg_mono-poly@yahoogroups.com, "dir_marillion" <dir_marillion@...> wrote:
>
> Hi, I understood.
>
> > Btw: it does not have to be the potentiometer itself. It could be >that the corresponding solder joint is corrupted.
>
> I just re-opened the synth and checked all lines of the pot which correspond to the solder joints to the motherboard. No corruptions found. Will recheck.
>
> The Synth is disconnected from power outlet and I am checking only if the lines are ok.
>
> Of course I have not idea which line is for VCO4 and it seems that schematics do not show this detail...
>
> --- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@> wrote:
> >
> > Hi
> >
> > > Can you explain me a little how this pot works and what should I do
> > > to test and/or fix it ?
> > The working principle of the portamento circuit is very simple. There is
> > an capacitor between ground and the control voltage line from the
> > keyboard for the VCO pitch. If the keyboard control voltage changes,
> > then its power will first be used to load the capacitor. This will take
> > some time. So the voltage change will not be immediate, but will
> > increase slowly. This causes at the VCO what we call portamento.
> > (The same happens if the voltage drops. Then the unloading will take
> > some time).
> >
> > As said, loading or unloading the capacitor always takes a little time,
> > but if the CV comes with enough current (if the power is high enough
> > (remember: power = voltage x current), then the loading or unloading of
> > the capacitor is that fast, that our ear does not recognize it.
> >
> > The portamento potentiometer now simply acts as a variable resistor (so
> > called rheostat) which is inserted in the CV-line before the capacitor.
> > If the poti is turned fully counterclockwise then the resulting resistor
> > is zero -> the capacitor will be loaded that fast, that we do not
> > recognize it.
> >
> > If the poti now gets turned clockwise, the resulting resistor is
> > increased -> the increased resistor means less current runs into the
> > capacitor -> the capacitor will be loaded slowlier -> the pitch changes
> > slowlier -> portamento.
> >
> >
> >
> > > Which is the line for VCO4 to shortcut and
> > > how can do this ?
> >
> > I cannot tell you exactly which layer of this four layer potentiometer
> > is the one for the VCO4, but I found an article in the web, which
> > describes the principle of our problem quite good
> >
> >
> > Have a look at http://www.allaboutcircuits.com/vol_6/chpt_3/7.html
> >
> > in the picture
> > http://sub.allaboutcircuits.com/images/05151.png
> > http://sub.allaboutcircuits.com/images/05150.png
> > you have to think the battery as the keyboard CV and the motor as the
> > capacitor. That is how the portamento potentiometer is wired.
> >
> >
> >
> >
> > The picture
> > http://sub.allaboutcircuits.com/images/05152.png
> > describes, what might be broken in your portamento potentiometer.
> >
> > If you connect both the outer connectors of the potentiometer with each
> > other, then it is like the potentiometers resistance would not be set to
> > zero.
> >
> >
> >
> >
> >
> > > Does it contain graphite like the sliders on JX3p
> > > ?
> > Yes. All potentiometers work like that, but you can't repair it with an
> > graphite spray!
> >
> > Btw: it does not have to be the potentiometer itself. It could be that
> > the corresponding solder joint is corrupted.
> >
> > Florian
> >
>

Hi

dir_marillion wrote:

> Check this photo: http://tinypic.com/r/34sfsb9/5

ok, now turn the potentiometer fully counterclock wise and in each layer
of the potentiometer measures the resistance between the left contact
and the center contact.

Florian

Hi,

All four measures seem to be the same:

http://tinypic.com/r/9r0nxv/5
http://tinypic.com/r/2j272gk/5
http://tinypic.com/r/v3zibo/5

Sorry the fourth picture was dark but it had the same result as the others.

--- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Hi
>
> dir_marillion wrote:
> > Check this photo: http://tinypic.com/r/34sfsb9/5
> ok, now turn the potentiometer fully counterclock wise and in each layer
> of the potentiometer measures the resistance between the left contact
> and the center contact.
>
> Florian
>

Hello

> All four measures seem to be the same:

Hmm. Now I have no further idea where to look for. Sorry.

Florian

Hi,
No problem Florian, you already did a lot to help me find what causes the issue. It seems that I have to give it for service in order to be checked further. Portamento potentiometer seems to work fine.

Maybe a TL chip is defective or something goes wrong to line from this pot to VCO4.

I will give it for service next weeks and I will let you know when I have the results.

Thank you very much

--- In korg_mono-poly@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Hello
>
> > All four measures seem to be the same:
> Hmm. Now I have no further idea where to look for. Sorry.
>
> Florian
>