Discussion about the Korg PolySix synthesizer

I am trying to restore a good old Polysix which suffered from the usual battery leakage and need some help to see on what areas I should focus. It has a KLM-367 board.

The battery was removed and the board cleaned up. The traces appear good, but I should test for continuity for sure. I re-populated the board, and did hear the Arpeggiator work with a nice sound. I could get Cutoff, Resonance and the Envelope to work.

What does not work:

- All Bank LEDs as well as 1, 2, 3, 4 remain ON.
- Found stays ON
- LFO appears to always act upon the pitch
- Voice 5 seems dead. A swap of both SSM chips on that segment did not change a thing
- Sub-osc does not seem to work
- Octave button does not seem to work

Any help on what to look for and procedures would be most welcome.

Yash

All the lights of the Bank as well as 1, 2, 3, 4 remain lit

 

=  setting klm-376 connect a 56 ohm 2p  ‘2pin’ for klm-376

Service manual  throughout the procedure and explain

 

Octave button not working  = the battery is necessarily a track cut or IC30
or 31 no longer works

 

LFO = IC21 13600 

 

Voice 5 seems dead. A swap of both = 2044 SSM   or diode led

 

Sub-osc = ic 13600

 

www.audio-synth-vintage.com

 

@+

philippe

 

 

De : PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] De la part de
7yash
Envoyé : lundi 8 octobre 2012 18:14
À : PolySix@yahoogroups.com
Objet : [PolySix] Polysix restoration: LEDs, Sub-Osc LFO issues.

 

  

I am trying to restore a good old Polysix which suffered from the usual
battery leakage and need some help to see on what areas I should focus. It
has a KLM-367 board.

The battery was removed and the board cleaned up. The traces appear good,
but I should test for continuity for sure. I re-populated the board, and did
hear the Arpeggiator work with a nice sound. I could get Cutoff, Resonance
and the Envelope to work.

What does not work:

- All Bank LEDs as well as 1, 2, 3, 4 remain ON.
- Found stays ON
- LFO appears to always act upon the pitch
- Voice 5 seems dead. A swap of both SSM chips on that segment did not
change a thing
- Sub-osc does not seem to work
- Octave button does not seem to work

Any help on what to look for and procedures would be most welcome.

Yash





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

At 13:43 Uhr +0000 08.10.2012, 7yash wrote:

> What does not work:
>
> - All Bank LEDs as well as 1, 2, 3, 4 remain ON.
> - Found stays ON
> - LFO appears to always act upon the pitch
> - Voice 5 seems dead. A swap of both SSM chips on that segment did not
>change a thing
> - Sub-osc does not seem to work
> - Octave button does not seem to work

This has probably something to do with data lines D01 to D03 which in turn
points at IC31 as the most likely culprit.

Please check if the the following also are affected:

- VCA Mode
- VCA Attenuator
- VCO Waveform

The dead voice 5 is unrelated; we can debug this at a later point.

Thanks Philippe and Malte. I will try the verifications.

I have also ordered some parts from Newark that should arrive soon so that I can use a new socket as well as try some new chips.

Will update as I go.

Great to see so many knowledgeable people who share freely!

Yash

--- In PolySix@yahoogroups.com, Malte Rogacki <gacki@...> wrote:

>
> At 13:43 Uhr +0000 08.10.2012, 7yash wrote:
> 
> > What does not work:
> >
> > - All Bank LEDs as well as 1, 2, 3, 4 remain ON.
> > - Found stays ON
> > - LFO appears to always act upon the pitch
> > - Voice 5 seems dead. A swap of both SSM chips on that segment did not
> >change a thing
> > - Sub-osc does not seem to work
> > - Octave button does not seem to work
> 
> This has probably something to do with data lines D01 to D03 which in turn
> points at IC31 as the most likely culprit.
> 
> Please check if the the following also are affected:
> 
> - VCA Mode
> - VCA Attenuator
> - VCO Waveform
> 
> The dead voice 5 is unrelated; we can debug this at a later point.
>

AFter some parts came from Newark, I did the following:

1. Mounted a socket and replaced two 74LS08N chips
2. Installed two LM13700N chips in place of the LM13600 chips

Results:

FIXED: - All Bank LEDs as well as 1, 2, 3, 4 remain ON.
FIXED: - Found stays ON
FIXED: - Sub-osc does not seem to work
FIXED: - Octave button does not seem to work

That's very encouraging!

VAC Mode works!
VCA Attenuator works!
Effects work!
VCO Waveform works!

What is not working:
LFO: LED stays on and cannot change the frequency.

Let me know what you think.

Thanks a lot, and have a great week-end.

Yash


--- In PolySix@yahoogroups.com, Malte Rogacki <gacki@...> wrote:

>
> At 13:43 Uhr +0000 08.10.2012, 7yash wrote:
> 
> > What does not work:
> >
> > - All Bank LEDs as well as 1, 2, 3, 4 remain ON.
> > - Found stays ON
> > - LFO appears to always act upon the pitch
> > - Voice 5 seems dead. A swap of both SSM chips on that segment did not
> >change a thing
> > - Sub-osc does not seem to work
> > - Octave button does not seem to work
> 
> This has probably something to do with data lines D01 to D03 which in turn
> points at IC31 as the most likely culprit.
> 
> Please check if the the following also are affected:
> 
> - VCA Mode
> - VCA Attenuator
> - VCO Waveform
> 
> The dead voice 5 is unrelated; we can debug this at a later point.
>

Actually these two things are not working:

1. The Filter controls: Cutoff, Resonance, etc...
2. The LFO section

Yash

--- In PolySix@yahoogroups.com, "7yash" <josh.nursing@...> wrote:

>
> AFter some parts came from Newark, I did the following:
> 
> 1. Mounted a socket and replaced two 74LS08N chips
> 2. Installed two LM13700N chips in place of the LM13600 chips
> 
> Results:
> 
> FIXED: - All Bank LEDs as well as 1, 2, 3, 4 remain ON.
> FIXED: - Found stays ON
> FIXED: - Sub-osc does not seem to work
> FIXED: - Octave button does not seem to work
> 
> That's very encouraging!
> 
> VAC Mode works!
> VCA Attenuator works!
> Effects work!
> VCO Waveform works!
> 
> What is not working:
> LFO: LED stays on and cannot change the frequency.
> 
> Let me know what you think.
> 
> Thanks a lot, and have a great week-end.
> 
> Yash
> 
> 
> --- In PolySix@yahoogroups.com, Malte Rogacki <gacki@> wrote:
> >
> > At 13:43 Uhr +0000 08.10.2012, 7yash wrote:
> > 
> > > What does not work:
> > >
> > > - All Bank LEDs as well as 1, 2, 3, 4 remain ON.
> > > - Found stays ON
> > > - LFO appears to always act upon the pitch
> > > - Voice 5 seems dead. A swap of both SSM chips on that segment did not
> > >change a thing
> > > - Sub-osc does not seem to work
> > > - Octave button does not seem to work
> > 
> > This has probably something to do with data lines D01 to D03 which in turn
> > points at IC31 as the most likely culprit.
> > 
> > Please check if the the following also are affected:
> > 
> > - VCA Mode
> > - VCA Attenuator
> > - VCO Waveform
> > 
> > The dead voice 5 is unrelated; we can debug this at a later point.
> >
>

I find it rather odd that initially, I could get the Cutoff/Resonance controls to work and that now they don't.

Yash

--- In PolySix@yahoogroups.com, "7yash" <josh.nursing@...> wrote:

>
> Actually these two things are not working:
> 
> 1. The Filter controls: Cutoff, Resonance, etc...
> 2. The LFO section
> 
> Yash

Where would I focus to try and restore the LFO and the Cutoff Frequency controls as well as the resonance controls?

I have tested continuity for D0 - D7 and they look good so I am stumped.

www.audio-synth-vintage.com

 

De : PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] De la part de
7yash
Envoyé : samedi 10 novembre 2012 07:49
À : PolySix@yahoogroups.com
Objet : [PolySix] Re: Polysix restoration: LEDs, Sub-Osc LFO issues.

 

  

Where would I focus to try and restore the LFO and the Cutoff Frequency
controls as well as the resonance controls?

I have tested continuity for D0 - D7 and they look good so I am stumped.





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

These are some fairly complex restorations, Philippe. Bravo !

I will need to test continuity more thoroughly today. The plan is to go over all of D0-D7 again and make a checklist of connections to test, as well as some of the P connections.

Thanks for the pointer.

Yash

--- In PolySix@yahoogroups.com, "philippe.69" <philippe.69@...> wrote:

>
> www.audio-synth-vintage.com
> 
>  
> 
> De : PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] De la part de
> 7yash
> Envoyé : samedi 10 novembre 2012 07:49
> À : PolySix@yahoogroups.com
> Objet : [PolySix] Re: Polysix restoration: LEDs, Sub-Osc LFO issues.
> 
>  
> 
>   
> 
> Where would I focus to try and restore the LFO and the Cutoff Frequency
> controls as well as the resonance controls?
> 
> I have tested continuity for D0 - D7 and they look good so I am stumped.
> 
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
>

I cannot do a complete Calibration and reset procedure, but on DAC calibration with Manual On and toggling Tape Enable off and on, I only manage to get LEDs 1 & 5 to light up. 

Changing VR6 & VR7 do nothing.

It looks like a previous member's issue, and it was recommended by Andy to reviews D05-D07 especially, so this is my next step.

It looks like the 4051, even on boards 369 and 370 might also need to be checked/swapped.

In my opinion this particular error is probably unrelated to the previous
problems.

If you look at the schematic you'll notice that those parameters are not
controlled via the D and P lines on CN06; instead the are multiplexed and
passed via CN11.
Could indeed be a 4051 or one of its lines acting up.

- LFO   =  if the LED still active and must be changed IC21 13600

 

De : PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] De la part de
Malte Rogacki
Envoyé : samedi 10 novembre 2012 21:57
À : PolySix@yahoogroups.com
Objet : [PolySix] Re: Polysix restoration: LEDs, Sub-Osc LFO issues.

 

  

In my opinion this particular error is probably unrelated to the previous
problems.

If you look at the schematic you'll notice that those parameters are not
controlled via the D and P lines on CN06; instead the are multiplexed and
passed via CN11.
Could indeed be a 4051 or one of its lines acting up.





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

Yes, the LFO LED works. I have changed the 13600's for 13700's.

Wish I could at least start to get some control over Cutoff Frequency & Resonance.

Current diagnosis:

VCF Cutoff: Not working
Resonance: Not Working
EG + Keyboard tracking: Not working

MG Frequency: Not working
Delay: Not working
Level: Not working

VGA ENV: 
Attack, Decay, Sustain, Release; Not working

PW/PWM: Not working
PWM Level: Not working

Yash

--- In PolySix@yahoogroups.com, "philippe.69" <philippe.69@...> wrote:

>
> - LFO   =  if the LED still active and must be changed IC21 13600
> 
>  
> 
> De : PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] De la part de
> Malte Rogacki
> Envoyé : samedi 10 novembre 2012 21:57
> À : PolySix@yahoogroups.com
> Objet : [PolySix] Re: Polysix restoration: LEDs, Sub-Osc LFO issues.
> 
>  
> 
>   
> 
> In my opinion this particular error is probably unrelated to the previous
> problems.
> 
> If you look at the schematic you'll notice that those parameters are not
> controlled via the D and P lines on CN06; instead the are multiplexed and
> passed via CN11.
> Could indeed be a 4051 or one of its lines acting up.
> 
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
>

Malte, thanks for the pointer to the 4051. It does look like they play a large part: if I remove the two main 4051s and plug them part way, they seem to have a drastic effect on the sound, especially regarding Cutoff/Res or Cutoff Res Env.

Yash

--- In PolySix@yahoogroups.com, Malte Rogacki <gacki@...> wrote:

>
> In my opinion this particular error is probably unrelated to the previous
> problems.
> 
> If you look at the schematic you'll notice that those parameters are not
> controlled via the D and P lines on CN06; instead the are multiplexed and
> passed via CN11.
> Could indeed be a 4051 or one of its lines acting up.
>

VCF Cutoff: = a check  ic 15 / 45600  for klm 366 

 

Resonance :   and necessarily a 5558 no remember what ic

 

De : PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] De la part de
7yash
Envoyé : samedi 10 novembre 2012 23:40
À : PolySix@yahoogroups.com
Objet : [PolySix] Re: Polysix restoration: LEDs, Sub-Osc LFO issues.

 

  

Yes, the LFO LED works. I have changed the 13600's for 13700's.

Wish I could at least start to get some control over Cutoff Frequency &
Resonance.

Current diagnosis:

VCF Cutoff: Not working
Resonance: Not Working
EG + Keyboard tracking: Not working

MG Frequency: Not working
Delay: Not working
Level: Not working

VGA ENV: 
Attack, Decay, Sustain, Release; Not working

PW/PWM: Not working
PWM Level: Not working

Yash

--- In  <mailto:PolySix%40yahoogroups.com> PolySix@yahoogroups.com,
"philippe.69" < <mailto:philippe.69@...> philippe.69@...> wrote:
>
> - LFO = if the LED still active and must be changed IC21 13600
> 
> 
> 
> De : PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
[mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> ] De la
part de
> Malte Rogacki
> Envoyé : samedi 10 novembre 2012 21:57
> À : PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> 
> Objet : [PolySix] Re: Polysix restoration: LEDs, Sub-Osc LFO issues.
> 
> 
> 
> 
> 
> In my opinion this particular error is probably unrelated to the previous
> problems.
> 
> If you look at the schematic you'll notice that those parameters are not
> controlled via the D and P lines on CN06; instead the are multiplexed and
> passed via CN11.
> Could indeed be a 4051 or one of its lines acting up.
> 
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
>





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

must look ic 30 and 31 are probably still something cut track

 

De : PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] De la part de
7yash
Envoyé : samedi 10 novembre 2012 23:40
À : PolySix@yahoogroups.com
Objet : [PolySix] Re: Polysix restoration: LEDs, Sub-Osc LFO issues.

 

  

Yes, the LFO LED works. I have changed the 13600's for 13700's.

Wish I could at least start to get some control over Cutoff Frequency &
Resonance.

Current diagnosis:

VCF Cutoff: Not working
Resonance: Not Working
EG + Keyboard tracking: Not working

MG Frequency: Not working
Delay: Not working
Level: Not working

VGA ENV: 
Attack, Decay, Sustain, Release; Not working

PW/PWM: Not working
PWM Level: Not working

Yash

--- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> ,
"philippe.69" <philippe.69@...> wrote:
>
> - LFO = if the LED still active and must be changed IC21 13600
> 
> 
> 
> De : PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
[mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> ] De la
part de
> Malte Rogacki
> Envoyé : samedi 10 novembre 2012 21:57
> À : PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> 
> Objet : [PolySix] Re: Polysix restoration: LEDs, Sub-Osc LFO issues.
> 
> 
> 
> 
> 
> In my opinion this particular error is probably unrelated to the previous
> problems.
> 
> If you look at the schematic you'll notice that those parameters are not
> controlled via the D and P lines on CN06; instead the are multiplexed and
> passed via CN11.
> Could indeed be a 4051 or one of its lines acting up.
> 
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
>





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

http://audio.synth.vintage.free.fr/modules.php?name=Forums&file=viewtopic&t=
113#509

 

De : PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] De la part de
7yash
Envoyé : samedi 10 novembre 2012 23:42
À : PolySix@yahoogroups.com
Objet : [PolySix] Re: Polysix restoration: LEDs, Sub-Osc LFO issues.

 

  

Malte, thanks for the pointer to the 4051. It does look like they play a
large part: if I remove the two main 4051s and plug them part way, they seem
to have a drastic effect on the sound, especially regarding Cutoff/Res or
Cutoff Res Env.

Yash

--- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Malte
Rogacki <gacki@...> wrote:
>
> In my opinion this particular error is probably unrelated to the previous
> problems.
> 
> If you look at the schematic you'll notice that those parameters are not
> controlled via the D and P lines on CN06; instead the are multiplexed and
> passed via CN11.
> Could indeed be a 4051 or one of its lines acting up.
>





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

Check Effects intensity. It probably won't work, too.

All those parameters are multiplexed and go through the 4051's.

Do you have an oscilloscope?

Effects intensity does seem to work.

I am without a scope currently.

After leaving it on for a few hours, I did get some control over Cutoff, Resonance, but it isn't stable, rather flaky.

Now, the lower LEDs will not light up and after a while will all light up starting from 1 and moving right.

Thanks also to Philipe, I will check that IC5 on KLM 366

Here is where we stand after starting the calibration procedure as I got myself a cool digital voltmeter which does not break the bank, and it does seem that I am nearing closer to final results (yay!)

1. Power Supply correctly re-calibrated to +15, -15, +5, -5 as closely as possible.

2. The TEST mode gives only LEDs 1 & 5 On, and no matter how much I play with VR6 and VR7, nothing changes there

3. Control over Cutoff, Resonance is flaky: sometimes it latches on, sometimes I lose that control

4. Output seems quite distorted when the Attenuator is on +10

Hey there -

Did the DAC issue everr get resolved? I', still stuck in this part of the calibration as well. Any help would be great!

If you are talking about getting the correct LEDs to light up during DAC
calibration on the clone boards, no I don't think anybody has a guaranteed
way to make this work. The last time I calibrated one of these, I ended up
just setting VR6 and VR7 by watching the DAC output on an oscilloscope and
listening to the factory sounds. I think I've heard those patches enough
that I can tell if they sound incorrect. I watched the scope to make sure
the DAC output was symmetrical in the negative and positive directions when
a knob was moved from 0 to 10, and showed 0V when the knob was in its center
position.

 

I tried substituting a 4560 instead of TL072 for IC27, as per the original
boards, but that just made things worse.

 

Don B.

 

  _____  

From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf Of
Boddington
Sent: Tuesday, January 29, 2013 5:38 PM
To: PolySix@yahoogroups.com
Subject: [PolySix] Re: Polysix restoration: LEDs, Sub-Osc LFO issues.

 

  

Hey there -

Did the DAC issue everr get resolved? I', still stuck in this part of the
calibration as well. Any help would be great!





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

Thanks for the reply, Don. Yes, that's where I'm at. I guess an oscialloscope is the next step. It sound like you actually managed to get past it though which is encouraging.

Replacing IC5 & IC6 allowed the DAC calibration to work correctly in my case.

Yash