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Key assign mode issue

Key assign mode issue

2015-04-16 by mpe1969@tpg.com.au

Hello, I have a problem with my polysix. Klm366. All the Key assign mode lights are stuck on and no voices working. Should I check IC1 (74l505) ?
My klm367 board is tested and works correctly.
Any suggestions?
Thank you


Re: [PolySix] Key assign mode issue

2015-04-16 by Florian Anwander

Hello

First question: did your Polysix ever suffer the known battery hazard?
Does it have a new battery now?

Florian

Am 16.04.2015 um 02:04 schrieb mpe1969@tpg.com.au [PolySix]:
>
> Hello, I have a problem with my polysix. Klm366. All the Key assign
> mode lights are stuck on and no voices working. Should I check IC1
> (74l505) ?
> My klm367 board is tested and works correctly.
> Any suggestions?
> Thank you
>
>

Re: [PolySix] Key assign mode issue

2015-04-16 by Tubbutec

Could be the key assigner cpu is not running at all. Check supply voltages.
Also check the connector between the two boards, especially the RESET line.
If you have a multimeter, check the voltage on the reset pin of the key assigner cpu. It should be high.
-- 
http://tubbutec.de
https://www.facebook.com/tubbu.tec


Am 16.04.2015 um 02:04 schrieb mpe1969@tpg.com.au [PolySix]:
 

Hello, I have a problem with my polysix. Klm366. All the Key assign mode lights are stuck on and no voices working. Should I check IC1 (74l505) ?
My klm367 board is tested and works correctly.
Any suggestions?
Thank you




  




    

    
    

      
Re: Key assign mode issue

      
2015-04-16 by mpe1969@tpg.com.au

      
Thanks. I have a spare tested and working Klm367 board which I am using for tests (with new battery).
I checked voltages going onto the klm366 board (all were good). But I will check the reset line  voltage and also connectors.
 I have disconnected the keyboard for tests and shorting the pins (to keyboard) as a test. 
Thanks again. 
 

    

    
    

      
Re: Key assign mode issue

      
2015-04-16 by mpe1969@tpg.com.au

      
Hi there, just checked voltage to Reset (4.9v)  and cpu voltage (5 v). Tonight none of the lights on the key assign buttons are working. Thanks again

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-04-16 by Bob Grieb

      
Is the oscillator running on the key assigner CPU?   Do you have an 
oscilloscope?

  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Thursday, April 16, 2015 6:29 AM
 Subject: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
Hi there, just checked voltage to Reset (4.9v)  and cpu voltage (5 v). Tonight none of the lights on the key assign buttons are working. Thanks again


    

     

    
    






 
 
  

    

    
    

      
Re: Key assign mode issue

      
2015-04-16 by mpe1969@tpg.com.au

      
I have an oscilloscope. (haven't used it for quite a while!). I'll pull it out tomorrow night, set it up and check out the oscillator. Keep you posted! Thanks again I appreciate the guidance. 

    

    
    

      
Re: Key assign mode issue

      
2015-04-17 by mpe1969@tpg.com.au

      
I just checked the oscillator on the Klm366 cpu with oscilloscope. I tested both sides of the crystal. I also tested the oscillator on the klm367 board. The results looked the same for both boards (square wave looking oscillations). So I assume  the oscillator is working is working. 

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-04-17 by Tubbutec

      

  
  
    use your oscilloscope to check if there is something on the data
    buses of the key assigner.. you should at least be able to see the
    key scanning..

    

    
Am 17.04.2015 um 13:40 schrieb
      mpe1969@tpg.com.au [PolySix]:

    

    
 
  
      
          

            
I just checked the oscillator on the Klm366 cpu with
                oscilloscope. I tested both sides of the crystal. I also
                tested the oscillator on the klm367 board. The results
                looked the same for both boards (square wave looking
                oscillations). So I assume  the oscillator is working is
                working. 

          

          
      
      
    

    

    
-- 
http://tubbutec.de
https://www.facebook.com/tubbu.tec

  




    

    
    

      
Re: Key assign mode issue

      
2015-04-17 by mpe1969@tpg.com.au

      
Does 'data buses' = pins 27 to 34 of 8049 heading to keyboard. Is this correct? Thanks

    

    
    
    
    

      
Re: Key assign mode issue

      
2015-04-17 by mpe1969@tpg.com.au

      
Thanks I checked them out.
Nothing on pins 12-15, the rest listed show something (a voltage)
Thanks again

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-04-17 by Tubbutec

      

  
  
    If the crystal oscillator is running, reset in is high but no
    signals on the bus:

    

    I would say the CPU is dead. Maybe someone else has an idea here,
    but that is my conclusion.

    

    I have a lot of spare key assigners here, because I replace them
    with my ModyPoly mod. I could probably send you one if you are
    willing to pay the postage..

    

    -tobias

    

    
Am 17.04.2015 um 14:24 schrieb
      mpe1969@tpg.com.au [PolySix]:

    

    
 
  
      
          

            
Thanks I checked them out.

            Nothing on pins 12-15, the rest listed show something (a
            voltage)
            
Thanks again

          

          
      
      
    

    

    
-- 
http://tubbutec.de
https://www.facebook.com/tubbu.tec

  




    

    
    

      
Re: Key assign mode issue

      
2015-04-17 by mpe1969@tpg.com.au

      
That sounds great, I'll recheck all tests again over the weekend (its getting late over here) and then get back to you. How should I contact you direct? Via your webpage (ModyPoly mod)? I can't see how to pm you in a yahoo group. Thanks again. 

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-04-17 by Florian Anwander

      
I agree. In theory also both 14175 could be dead and pull down the 

D-bus. But since a replacement is available quite easy via Tobias, it is 

not worth to fiddle around with other potential causes.



Florian



Am 17.04.2015 um 14:32 schrieb Tubbutec mail@tubbutec.de [PolySix]:


 >

> If the crystal oscillator is running, reset in is high but no signals 

> on the bus:

>

> I would say the CPU is dead. Maybe someone else has an idea here, but 

> that is my conclusion.

>

> I have a lot of spare key assigners here, because I replace them with 

> my ModyPoly mod. I could probably send you one if you are willing to 

> pay the postage..

>

> -tobias

> 

    

    
    
    
    

      
Re: Key assign mode issue

      
2015-04-17 by swamp.gigs@googlemail.com

      
I had a similar problem... it was from damaged traces along the edge next to the 367. In my case, pin 40 on the assigner, and a power line need reconnected... 

Have you checked the continuity around that area ?

I'l like to thank Florian for his upload of different version of the service manual. The schematics are much easier to read !

Cheers - Tony

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-04-17 by Chromatest J. Pantsmaker

      
Interesting....  I hadn't realized that the yahoo groups web-interface doesn't show any email addresses at all.  I get all of my yahoo groups messages via email, so I see your email addresses.

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-04-17 by Bob Grieb

      
Since you have a scope, you may want to check all pins
at the key assigner and let us know if you see anything interesting.
Any activity on any outputs other than the oscillator might give us 
a clue as to what is going on.  Collateral damage from a battery 
leak could interfere with the key assigner CPU, as mentioned already.

Swapping out the MCU is a great idea, but in the mean time...

    Bob

  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Friday, April 17, 2015 8:55 AM
 Subject: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
That sounds great, I'll recheck all tests again over the weekend (its getting late over here) and then get back to you. How should I contact you direct? Via your webpage (ModyPoly mod)? I can't see how to pm you in a yahoo group. Thanks again. 


    

     

    
    






 
 
  

    

    
    

      
Re: Key assign mode issue

      
2015-04-30 by mpe1969@tpg.com.au

      
I replaced the cpu (thanks) and now my six diodes light up when testing (super). However... I still have issues. I only get a ticking sound. My filter and resonance are working but all working keys produce the same ticking sound. (Changing the wave shape does not alter this). So I still have more issues.
If anyone has any suggestions, I'd appreciate the guidance.
Thanks again.

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-04-30 by Bob Grieb

      
If the oscillators are not running, then you could still get a ticking 
sound due to the VCA opening and closing.  As I recall you have a scope,
so maybe focus on just one voice and see if the oscillator is running when the 
LED is on (which means the gate signal is high).   It seems unlikely that all of 
the oscillators would have died at the same time.  

Set the filter to all the way open, and the sustain to max, and the mode to manual,
not a patch, and find IC33 of voice 6.   Pin 7 of that chip should be the 
output of that voice.  And the same point on the other voices should be their 
outputs.  When you hold the key down, you should have a nice waveform at
that point if the LED is on.   If not, work your way back from there to see 
where it stops.

   Bob

  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Thursday, April 30, 2015 8:21 AM
 Subject: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
I replaced the cpu (thanks) and now my six diodes light up when testing (super). However... I still have issues. I only get a ticking sound. My filter and resonance are working but all working keys produce the same ticking sound. (Changing the wave shape does not alter this). So I still have more issues.
If anyone has any suggestions, I'd appreciate the guidance.
Thanks again.


    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-01 by mpe1969@tpg.com.au

      
Thanks Bob. I had a look tonight. All I get on that pin is a noise looking wave. I was reading some earlier messages on this forum last night and thought I would probe r152.  (Vco input) all I get on that resistor is a saw tooth wave shape about -8 dc. But what is weird is that when then oscilloscope probe is touching that resistor I get sound out the headphones for that oscillator. I can change the wave shape of that wave and alter it with the filter. Still just the same tone (key) though. This seems to be pointing to a faulty 14051?
Also when I put the hold button on  and push sound keys (1 after the other) all the oscillator diode lights turn on) I would have expected the previous one to turn off when the next one turns on...
Not sure what to make of this as yet. 
Thanks again.

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-01 by Bob Grieb

      
Hi,

   Normally I would agree with you that not having good voltages at R152 would indicate the 4051
would be bad, but if the gate LED's are not shutting off, but only turning on, that indicates a digital
problem around the key assigner and gate latch area.   Sounds like you may still have a problem
in that part of the circuit, which could interfere with the key assigner selecting the 4051 properly.
You can check the digital control inputs to the 4051 and see if they look OK.   Actually, I uploaded 
some waveforms a while back to the files area that show some of these signals.

   If you can set it up, trigger your scope on the latch enable signal to the gate latch chip, pin 9 of IC5.
With the other probe, look at the data input to the latch for gate 0.   If you don't have a storage 
scope you may need to press the key a bunch of times to see what's happening.   Actually, using 
the arpeggiator might allow you to write to that latch at a faster rate and see the signal 
better.   Anyway, you want to see what voltage level is on the data input when the latch enable
signal is high.   A good high level should be about 4V or so, and a low level should be maybe 0.5V or less.

  Did you check the power supply inputs to the KLM-366 board?

    I would scope all of the key assigner MCU signals on the top side of the chip in the schematic,
and see if you have good logic levels on all of them.  Something strange is happening here.

     Bob



  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Friday, May 1, 2015 8:37 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
Thanks Bob. I had a look tonight. All I get on that pin is a noise looking wave. I was reading some earlier messages on this forum last night and thought I would probe r152.  (Vco input) all I get on that resistor is a saw tooth wave shape about -8 dc. But what is weird is that when then oscilloscope probe is touching that resistor I get sound out the headphones for that oscillator. I can change the wave shape of that wave and alter it with the filter. Still just the same tone (key) though. This seems to be pointing to a faulty 14051?
Also when I put the hold button on  and push sound keys (1 after the other) all the oscillator diode lights turn on) I would have expected the previous one to turn off when the next one turns on...
Not sure what to make of this as yet. 
Thanks again.


    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-01 by Dave Garfield

      
Dear Group,
My humble apologies beforehand, but:

"When there's something strange,
In your Poly - six,
Who ya' gonna' call?
BOB GRIEBSTER!"

WARNING: Original song contained analogue synths...  Do Not ingest digitally!
  


 
 
 
  On Friday, May 1, 2015 9:17 AM, "Bob Grieb bobgrieb@yahoo.com [PolySix]" <PolySix@yahoogroups.com> wrote:
  
  

 

 






  





    



      
Hi,

   Normally I would agree with you that not having good voltages at R152 would indicate the 4051
would be bad, but if the gate LED's are not shutting off, but only turning on, that indicates a digital
problem around the key assigner and gate latch area.   Sounds like you may still have a problem
in that part of the circuit, which could interfere with the key assigner selecting the 4051 properly.
You can check the digital control inputs to the 4051 and see if they look OK.   Actually, I uploaded 
some waveforms a while back to the files area that show some of these signals.

   If you can set it up, trigger your scope on the latch enable signal to the gate latch chip, pin 9 of IC5.
With the other probe, look at the data input to the latch for gate 0.   If you don't have a storage 
scope you may need to press the key a bunch of times to see what's happening.   Actually, using 
the arpeggiator might allow you to write to that latch at a faster rate and see the signal 
better.   Anyway, you want to see what voltage level is on the data input when the latch enable
signal is high.   A good high level should be about 4V or so, and a low level should be maybe 0.5V or less.

  Did you check the power supply inputs to the KLM-366 board?

    I would scope all of the key assigner MCU signals on the top side of the chip in the schematic,
and see if you have good logic levels on all of them.  Something strange is happening here.

     Bob



  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Friday, May 1, 2015 8:37 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 






  





    



      
Thanks Bob. I had a look tonight. All I get on that pin is a noise looking wave. I was reading some earlier messages on this forum last night and thought I would probe r152.  (Vco input) all I get on that resistor is a saw tooth wave shape about -8 dc. But what is weird is that when then oscilloscope probe is touching that resistor I get sound out the headphones for that oscillator. I can change the wave shape of that wave and alter it with the filter. Still just the same tone (key) though. This seems to be pointing to a faulty 14051?
Also when I put the hold button on  and push sound keys (1 after the other) all the oscillator diode lights turn on) I would have expected the previous one to turn off when the next one turns on...
Not sure what to make of this as yet. 
Thanks again.



    





    








 
 
  



    





    








  
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-02 by Bob Grieb

      
Does this mean I am over-posting?  Maybe I need a vacation...
:-)


  
 
 
    From: "Dave Garfield daveogarf@yahoo.com [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Friday, May 1, 2015 5:52 PM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
Dear Group,
My humble apologies beforehand, but:

"When there's something strange,
In your Poly - six,
Who ya' gonna' call?
BOB GRIEBSTER!"

WARNING: Original song contained analogue synths...  Do Not ingest digitally!
  


 
 
 
  On Friday, May 1, 2015 9:17 AM, "Bob Grieb bobgrieb@yahoo.com [PolySix]" <PolySix@yahoogroups.com> wrote:
  
  

 

 






  





    

      
      
      
Hi,

   Normally I would agree with you that not having good voltages at R152 would indicate the 4051
would be bad, but if the gate LED's are not shutting off, but only turning on, that indicates a digital
problem around the key assigner and gate latch area.   Sounds like you may still have a problem
in that part of the circuit, which could interfere with the key assigner selecting the 4051 properly.
You can check the digital control inputs to the 4051 and see if they look OK.   Actually, I uploaded 
some waveforms a while back to the files area that show some of these signals.

   If you can set it up, trigger your scope on the latch enable signal to the gate latch chip, pin 9 of IC5.
With the other probe, look at the data input to the latch for gate 0.   If you don't have a storage 
scope you may need to press the key a bunch of times to see what's happening.   Actually, using 
the arpeggiator might allow you to write to that latch at a faster rate and see the signal 
better.   Anyway, you want to see what voltage level is on the data input when the latch enable
signal is high.   A good high level should be about 4V or so, and a low level should be maybe 0.5V or less.

  Did you check the power supply inputs to the KLM-366 board?

    I would scope all of the key assigner MCU signals on the top side of the chip in the schematic,
and see if you have good logic levels on all of them.  Something strange is happening here.

     Bob



  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Friday, May 1, 2015 8:37 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 






  





    

      
      
      
Thanks Bob. I had a look tonight. All I get on that pin is a noise looking wave. I was reading some earlier messages on this forum last night and thought I would probe r152.  (Vco input) all I get on that resistor is a saw tooth wave shape about -8 dc. But what is weird is that when then oscilloscope probe is touching that resistor I get sound out the headphones for that oscillator. I can change the wave shape of that wave and alter it with the filter. Still just the same tone (key) though. This seems to be pointing to a faulty 14051?
Also when I put the hold button on  and push sound keys (1 after the other) all the oscillator diode lights turn on) I would have expected the previous one to turn off when the next one turns on...
Not sure what to make of this as yet. 
Thanks again.



    

     


    
    








 
 
  



    

     


    
    








  
 
  


    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-02 by Dave Garfield

      
Dear Bob,
Oh my, NO!  NOT over-posting!  Rather, it means that you are our go-to source for in-depth knowledge about the quirks and shortcomings of the Korg Polysix, and you have helped us all out so much in expanding our knowledge and repair wizardry of this synth.
I thank you humbly for all your contributions, and urge you to please keep enlightening us.
Thanks again!
Dave Garfield - who experienced a moment of silly, and have reverted to my old dull self...
  


 
 
 
  On Saturday, May 2, 2015 4:02 PM, "Bob Grieb bobgrieb@yahoo.com [PolySix]" <PolySix@yahoogroups.com> wrote:
  
  

 

 




  



    

      
      
      
Does this mean I am over-posting?  Maybe I need a vacation...
:-)


  
 
 
    From: "Dave Garfield daveogarf@yahoo.com [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Friday, May 1, 2015 5:52 PM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
Dear Group,
My humble apologies beforehand, but:

"When there's something strange,
In your Poly - six,
Who ya' gonna' call?
BOB GRIEBSTER!"

WARNING: Original song contained analogue synths...  Do Not ingest digitally!
  


 
 
 
  On Friday, May 1, 2015 9:17 AM, "Bob Grieb bobgrieb@yahoo.com [PolySix]" <PolySix@yahoogroups.com> wrote:
  
  

 

 






  





    

      
      
      
Hi,

   Normally I would agree with you that not having good voltages at R152 would indicate the 4051
would be bad, but if the gate LED's are not shutting off, but only turning on, that indicates a digital
problem around the key assigner and gate latch area.   Sounds like you may still have a problem
in that part of the circuit, which could interfere with the key assigner selecting the 4051 properly.
You can check the digital control inputs to the 4051 and see if they look OK.   Actually, I uploaded 
some waveforms a while back to the files area that show some of these signals.

   If you can set it up, trigger your scope on the latch enable signal to the gate latch chip, pin 9 of IC5.
With the other probe, look at the data input to the latch for gate 0.   If you don't have a storage 
scope you may need to press the key a bunch of times to see what's happening.   Actually, using 
the arpeggiator might allow you to write to that latch at a faster rate and see the signal 
better.   Anyway, you want to see what voltage level is on the data input when the latch enable
signal is high.   A good high level should be about 4V or so, and a low level should be maybe 0.5V or less.

  Did you check the power supply inputs to the KLM-366 board?

    I would scope all of the key assigner MCU signals on the top side of the chip in the schematic,
and see if you have good logic levels on all of them.  Something strange is happening here.

     Bob



  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Friday, May 1, 2015 8:37 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 






  





    

      
      
      
Thanks Bob. I had a look tonight. All I get on that pin is a noise looking wave. I was reading some earlier messages on this forum last night and thought I would probe r152.  (Vco input) all I get on that resistor is a saw tooth wave shape about -8 dc. But what is weird is that when then oscilloscope probe is touching that resistor I get sound out the headphones for that oscillator. I can change the wave shape of that wave and alter it with the filter. Still just the same tone (key) though. This seems to be pointing to a faulty 14051?
Also when I put the hold button on  and push sound keys (1 after the other) all the oscillator diode lights turn on) I would have expected the previous one to turn off when the next one turns on...
Not sure what to make of this as yet. 
Thanks again.



    

     


    
    








 
 
  



    

     


    
    








  
 
  


    

     

    
    






 
 
  


    

     

    
    






  
 
  

    

    
    

      
Re: Key assign mode issue

      
2015-05-03 by mpe1969@tpg.com.au

      
Hi there, I've been away for the weekend but managed to have a quick look tonight. My oscilloscope is a primitive analogue so I'm a little limited. However I had a look at the pin 9 of of ic4 and ic5. They both seem to have the same 'small  fast clock-like pattern (for want of better description). I checked gates 0-5 and all send  out a 4v (my arp switch is broken - my replacements arrived last fri so will repair this week). I push a key 6 times and on each gate I will get 4v - one in six hits.
My lights do turn off on poly but not when hold is selected.

I checked power on all ic's  around this area and they are getting the 5v dc (pin 16).
Other points noted:
Nothing on outputs from ic2 (will recheck this in the next few days)
ic 131 5vc on pin16, but -10dc appears on most of c131's outputs (constant)
I checked some outputs on the main cpu, most that I tested showed a square wave looking shape. 

Once again, I will redo these checks next week. (and gather some more accurate info) 
I just got home and thought I would have a quick look.
Thanks once again.

 

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-03 by Bob Grieb

      
Hi again,

    Now I am thinking that the gate LED's staying on was due to hold mode
and it sounds like the gates are working OK when you are in poly mode, so 
I will assume that the key assigner MCU is working correctly.

   You said that the outputs of the 4051 are -10v, so maybe your original 
idea was correct, that this chip is bad.   Please check the DAC output
at pin 1 of IC9.   It should be cycling between several different levels
if several keys are pressed.   Then check pin 3 of IC39 and also pin 3 
of IC 31 and tell us what you see.  Maybe the anti-log circuit is 
not working.

    When looking at digital signals, its important to note if the logic levels 
look OK.   The low level should be within maybe 0.5 volts of gnd.   The high level
should be 4V or higher usually.   If you see mid-levels it's usually a problem, unless
you are looking at a tri-state data bus, like on memory chips.   That bus will float
when nothing is being accessed, and can be in the middle at that time.

   Also, if the logic is 4000 series and is being operated at 12V or more, then the 
logic levels would be much higher.   But it can also be operated at 5V, like IC31 and 39,
and use std levels.

     Bob

  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Sunday, May 3, 2015 7:40 AM
 Subject: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
Hi there, I've been away for the weekend but managed to have a quick look tonight. My oscilloscope is a primitive analogue so I'm a little limited. However I had a look at the pin 9 of of ic4 and ic5. They both seem to have the same 'small  fast clock-like pattern (for want of better description). I checked gates 0-5 and all send  out a 4v (my arp switch is broken - my replacements arrived last fri so will repair this week). I push a key 6 times and on each gate I will get 4v - one in six hits.
My lights do turn off on poly but not when hold is selected.

I checked power on all ic's  around this area and they are getting the 5v dc (pin 16).
Other points noted:
Nothing on outputs from ic2 (will recheck this in the next few days)
ic 131 5vc on pin16, but -10dc appears on most of c131's outputs (constant)
I checked some outputs on the main cpu, most that I tested showed a square wave looking shape. 

Once again, I will redo these checks next week. (and gather some more accurate info) 
I just got home and thought I would have a quick look.
Thanks once again.

 


    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-04 by mpe1969@tpg.com.au

      
Thanks, I had another look tonight. I tried to upload some oscilloscope photos but they didn't seem to save to my album. 
IC9 has a dc around -2 to 2.5v that rises to about -0.5 then drops to around -4v then returns to around -2.5v. (as a pattern) I took some photos..... Hitting keys does not seem to influence this pattern
Ic39 (the one above ic31) does not have anything happening on pin3. IC31 has -10v on pin3.
I was about to replace ic31 but thought I would hold off as ic9 doesn't seem to be doing what you described.
Will try again with the photos!
Thanks again

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-04 by Bob Grieb

      
Actually, IC39-3 is a virtual ground node due to op amp IC19, so it should be sitting 
at 0V all the time.   My mistake.   But how about pin 7 of IC 19?   This is also called
TP2.    If pin 3 of IC31 is sitting at -10V, then the outputs would probably be at that 
voltage, as you have said before, so maybe that chip is OK.   IC9-1 should have something 
like 5-8 different voltage levels if you hold 5 notes.   According to the schematic, it's about 
0.5V / octave, so you should be able to see this voltage changing as you play 
different notes.   The total time is divided into ~8 different time slots, and the voltages
for the 5 notes are each assigned to one of these time slots.   If you play low C, then the 
next C up, then the next C, etc, until you have 5 oscillators on (use hold mode for this)
than at IC9 you should see 5 levels, each 0.5 volts apart.   If you play the notes in 
ascending order, I think you may see a stair step pattern at IC9-1 with the voltage increasing
0.5V each step, then jumping back down at the end.  There will be a couple of other levels
in there as well, but you should be able to see 5 levels repeated which correspond to your notes.
If you don't see that at IC9-1, then maybe check each output of IC7 and 8 for good digital levels.

IC9-1 should be -10.7/10 times whatever you have at IC9-7 with ~5V added to it.   

  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Monday, May 4, 2015 7:12 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
Thanks, I had another look tonight. I tried to upload some oscilloscope photos but they didn't seem to save to my album. 
IC9 has a dc around -2 to 2.5v that rises to about -0.5 then drops to around -4v then returns to around -2.5v. (as a pattern) I took some photos..... Hitting keys does not seem to influence this pattern
Ic39 (the one above ic31) does not have anything happening on pin3. IC31 has -10v on pin3.
I was about to replace ic31 but thought I would hold off as ic9 doesn't seem to be doing what you described.
Will try again with the photos!
Thanks again


    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Key assign mode issue

      
2015-05-04 by Ben Stuyts

      
Hi,



Your photos are now available in your photo album. I have photo upload set to moderated because of spammers abusing it in the past.



Ben (Moderator)




 > On 04 May 2015, at 13:12, mpe1969@tpg.com.au [PolySix] <PolySix@yahoogroups.com> wrote:

> 

> 

> 

> Thanks, I had another look tonight. I tried to upload some oscilloscope photos but they didn't seem to save to my album. 

> IC9 has a dc around -2 to 2.5v that rises to about -0.5 then drops to around -4v then returns to around -2.5v. (as a pattern) I took some photos..... Hitting keys does not seem to influence this pattern

> Ic39 (the one above ic31) does not have anything happening on pin3. IC31 has -10v on pin3.

> I was about to replace ic31 but thought I would hold off as ic9 doesn't seem to be doing what you described.

> Will try again with the photos!

> Thanks again

> 

> 

> 

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-04 by Bob Grieb

      
If you post any more photos, please use more of the screen by setting the volts/div smaller,
so that we can see more detail.   Also, please tell us what the setting is so that we can 
interpret what we are seeing.   Also, we need to know where ground is on the scope.

And on a waveform that's repeating, usually you would zoom in so that one cycle of
it fills the screen.   Then say that it was repeating.   That way we can see the most
detail.

Thanks
  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Monday, May 4, 2015 7:12 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
Thanks, I had another look tonight. I tried to upload some oscilloscope photos but they didn't seem to save to my album. 
IC9 has a dc around -2 to 2.5v that rises to about -0.5 then drops to around -4v then returns to around -2.5v. (as a pattern) I took some photos..... Hitting keys does not seem to influence this pattern
Ic39 (the one above ic31) does not have anything happening on pin3. IC31 has -10v on pin3.
I was about to replace ic31 but thought I would hold off as ic9 doesn't seem to be doing what you described.
Will try again with the photos!
Thanks again


    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-04 by mpe1969@tpg.com.au

      
No problem, I will have another go at taking photo's tonight. (flash doesn't work on screen so will set up a small tripod. Thanks again. I can say that I was repeating hitting the same note so this may have influenced the 'no change' in voltage on ic9 pin 1 maybe. In the photo that has the smaller wave the grid is 5v = one line, and on the other larger photo line: 5v = two grid lines. Will repeat photos again with oscilloscope settings etc. Thanks once again for the assistance.

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-05 by mpe1969@tpg.com.au

      
I have just added three more photos. 
Results from tonight. 
IC 7 and IC8 seem to be ok. (inverting voltages) Except pin 13 on ic7 voltage present butis a little jumpy across oscilloscope.
IC19 pin 7 looks similar to the wave on ic9 pin1 (see photos). Pushing keys does not influence the voltage.
IC9 pin1,2,6,7 all look the same (see photo1). Pin 5 has a very distorted variation of pin1 (see photo). 
(pin4 -15, pin8 15+.
I have added oscilloscope setting to photos.

I'm wondering if ic9 is faulty.
Thanks again (learning curve going on over here).
Hope these photos are a little more informative.


    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-05 by Bob Grieb

      
IC9 pin 2 should be at 0V all the time.  If you have a waveform at pin 2, I 
would replace IC9.  Also, your photos say 0.5V/division.   Are you using a 10:1
scope probe?  If so, maybe it's really 5V/division?   That would make the waveforms
closer to what I would expect, if you are playing 5 keys that are each an octave 
apart.   That's a better test at this pt than playing keys that are together on the 
keyboard.

Are you saying that the waveform at IC9-7 does not change when you press keys?

Press 5 keys that are adjacent on the keyboard and look at IC9-7, then press
5 C keys that are octaves apart.   In the second case, the steps in the waveform
should be about 1/2 volt apart.

    Actually the waveform at IC9-5 looks OK to me, assuming it's 5V/div and 
not 0.5    You are not triggering the scope properly, though, since we can see 
a hor line through the waveform.   It will be easier to trigger correctly if
you can get the waveform to fill more of the screen.    Then play with the trigger
level.    Use normal trigger mode, not auto.   

You need to sort out whether your scope probe is 10:1 or not.   If you can get to 
0.5 volts per division, it should make the waveforms easier for us to look at.
(I suspect you may be at 5V / division currently).  

Anyway, it is starting to look like IC9 may be bad.   If you decide to change it, 
the preferred method is to cut each lead close to the body of the chip.   Remove the 
body, then heat each lead individually from the top side of the bd and pull out the 
lead.   Check first to see if any leads are bent underneath, as the corner ones often are.
You may have to straighten them before they will come out.

 Put a socket in for any new chip you install.   They are cheap, and on these old circuit
bds, you may only get one chip change per location before the traces start lifting up.

    Bob

  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Tuesday, May 5, 2015 7:09 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
I have just added three more photos. 
Results from tonight. 
IC 7 and IC8 seem to be ok. (inverting voltages) Except pin 13 on ic7 voltage present butis a little jumpy across oscilloscope.
IC19 pin 7 looks similar to the wave on ic9 pin1 (see photos). Pushing keys does not influence the voltage.
IC9 pin1,2,6,7 all look the same (see photo1). Pin 5 has a very distorted variation of pin1 (see photo). 
(pin4 -15, pin8 15+.
I have added oscilloscope setting to photos.

I'm wondering if ic9 is faulty.
Thanks again (learning curve going on over here).
Hope these photos are a little more informative.



    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-05 by mpe1969@tpg.com.au

      
Thanks (just about to go to bed, but did another quick check). IC9 pin2 is definately  showing the same as pin 1. (problem)
The oscilloscope works in reverse:
.5 = 10v/ 2cm, 
1 = 10v/1cm, 
2 = 10v/2.5cm.
So in these photo's 2cm =10v approx
It's an old Australian made oscilloscope called a bwd 539d. I'll have another go with it tomorrow night (will turn off auto!) I've mainly just used it for audio in the past. 

Thanks again, I will also change over ic9 tomorrow night. (thanks for the tips)

    

    
    

      
Re: Key assign mode issue

      
2015-05-05 by radek.tymecki@op.pl

      
Tobias, it seems my CPU from key assigner is also dead. Is there any chance to get one from You?

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-05 by Bob Grieb

      
Your scope looks quite usable.   25 MHz should be OK for what you will find in 
most synths.    You will get a little rounding of corners, but overall it should be 
plenty good.

Op amp circuits that have feedback around the chip, like voltage followers,
or inverting or non-inverting amplifiers, are easy to analyze with just two basic rules.

1) The op amp will move its output to try to keep the two inputs at the same voltage.

2) The two inputs will draw essentially no current from the circuity that feeds them.

The second is an approximation, but works fine in most cases.   So for IC9 pin 2,
there is feedback around the op amp and this is just an amplifier.  Since pin 3
is tied to gnd, we know that the op amp should be trying to set its output so that pin 2
is also at ground.   Since that's not what you are seeing, then the op amp is suspect.

   If the op amp is something special, like an OTA (LM13600, CA3080) or an LM3900,
then the above rules don't apply.

    Bob
 

  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Tuesday, May 5, 2015 9:18 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
Thanks (just about to go to bed, but did another quick check). IC9 pin2 is definately  showing the same as pin 1. (problem)
The oscilloscope works in reverse:
.5 = 10v/ 2cm, 
1 = 10v/1cm, 
2 = 10v/2.5cm.
So in these photo's 2cm =10v approx
It's an old Australian made oscilloscope called a bwd 539d. I'll have another go with it tomorrow night (will turn off auto!) I've mainly just used it for audio in the past. 

Thanks again, I will also change over ic9 tomorrow night. (thanks for the tips)


    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-06 by mpe1969@tpg.com.au

      
Good news. I replaced ic9 (added socket) and I have some action!
I am now getting sounds! The oscilloscope showed more positive voltages on ic9 leg1 and when ! hold down a cluster of notes I get an extra line (lower voltage for low note). 
I also replaced two switches: arpeggiator and hold. (hold was on its way out, arpeggiator didn't work)
Arpeggiator is now working however not the up and down octave switches (will clean the switch tomorrow night). 
Other issues:
Hold still does not turn off the previous note.
My sixth oscillator is also about a semi-tone sharp.
But it's great to hear some sounds! Filters and ADSR working
 
Will take some photos tomorrow night.
Kudos to Bob! Thanks again.
 

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-06 by Chromatest J. Pantsmaker

      
It's been a while since I've played with my P6 (shame on me), but I'm thinking that HOLD should keep playing that note until HOLD is released.  I feel like that's how mine works.

 
On Wed, May 6, 2015 at 5:23 AM, mpe1969@tpg.com.au [PolySix] <PolySix@yahoogroups.com> wrote:







        


















Good news. I replaced ic9 (added socket) and I have some action!
I am now getting sounds! The oscilloscope showed more positive voltages on ic9 leg1 and when ! hold down a cluster of notes I get an extra line (lower voltage for low note). 
I also replaced two switches: arpeggiator and hold. (hold was on its way out, arpeggiator didn't work)
Arpeggiator is now working however not the up and down octave switches (will clean the switch tomorrow night). 
Other issues:
Hold still does not turn off the previous note.
My sixth oscillator is also about a semi-tone sharp.
But it's great to hear some sounds! Filters and ADSR working
 
Will take some photos tomorrow night.
Kudos to Bob! Thanks again.
 


























    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-06 by Tubbutec

      

  
  
    yes this is the whole idea with hold ...

    

    
Am 06.05.2015 um 15:25 schrieb
      'Chromatest J. Pantsmaker' chromatest@azburners.org [PolySix]:

    

    
 
  
      
          

            
It's been a while since I've played with my
              P6 (shame on me), but I'm thinking that HOLD should keep
              playing that note until HOLD is released.  I feel like
              that's how mine works.

            


              
On Wed, May 6, 2015 at 5:23 AM, mpe1969@tpg.com.au
                [PolySix] <PolySix@yahoogroups.com>
                wrote:

                

                  

                    

                    

                    Good news. I replaced ic9 (added socket) and I have
                    some action!
                    
I am now getting sounds! The oscilloscope
                      showed more positive voltages on ic9 leg1 and when
                      ! hold down a cluster of notes I get an extra line
                      (lower voltage for low note). 

                    
I also replaced two switches: arpeggiator and
                      hold. (hold was on its way out, arpeggiator didn't
                      work)

                    
Arpeggiator is now working however not the up
                      and down octave switches (will clean the switch
                      tomorrow night). 

                    
Other issues:

                    
Hold still does not turn off the previous note.

                    
My sixth oscillator is also about a semi-tone
                      sharp.

                    
But it's great to hear some sounds! Filters and
                      ADSR working

                    
 

                    
Will take some photos tomorrow night.

                    
Kudos to Bob! Thanks again.

                    
 

                    

                    

                  

                

              

              

            

          

          
      
      
    

    

    
-- 
http://tubbutec.de
https://www.facebook.com/tubbu.tec

  




    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-06 by Bob Grieb

      
That's great news.   Since the anti-log circuit is shared by all six
voices, if just one osc is sharp, then you would just tune that one.
As has been mentioned before here, best to leave the anti-log pots 
alone unless you have a good reason to touch them.   Probably you 
should check/adjust the tuning on all six voices just for fun.

I guess it's better not to adjust the power supply voltages unless
you are prepared to go through the full calibration procedure.

Bob

  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Wednesday, May 6, 2015 8:23 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
Good news. I replaced ic9 (added socket) and I have some action!
I am now getting sounds! The oscilloscope showed more positive voltages on ic9 leg1 and when ! hold down a cluster of notes I get an extra line (lower voltage for low note). 
I also replaced two switches: arpeggiator and hold. (hold was on its way out, arpeggiator didn't work)
Arpeggiator is now working however not the up and down octave switches (will clean the switch tomorrow night). 
Other issues:
Hold still does not turn off the previous note.
My sixth oscillator is also about a semi-tone sharp.
But it's great to hear some sounds! Filters and ADSR working
 
Will take some photos tomorrow night.
Kudos to Bob! Thanks again.
 


    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-07 by mpe1969@tpg.com.au

      
Right. So hold is working (ha). I'm used to mono synths where the next key pushed changes rather than adds the next pitch - as in the unison selection on the polysix). So all is good. Thanks
I replaced a few more button switches tonight.
The arpeggiator is working. (however I have the below mentioned issue still)

I still have issues. I tuned the 6th oscillator (trim 10 and 11). It seems fine. However when I add the octave lower (or second octave) it seems to push the 6th oscillator higher an octave. Arpeggiator also sends the 6th oscillator an octave higher. 
The other issue I have is when I play a low note then a high note I get a ghosting (like an extra pitch with pulsing) for a few hits of the high note. If I continue to repeat hitting the high note, the ghosting (for want of a better word) disappears and the pitch becomes clean. This can happen on any oscillator. 
The same happens in reverse: hit a high key then a low key, the same ghosting occurs for a while. 
I will clean up the key bed on the weekend as I'm working with about 60 percent of my keys.
Thanks again. I will fire up the oscilloscope again over the weekend


    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-07 by Bob Grieb

      
When I bought my PolySix, so many keys were out that I thought 
I had a circuit problem.   But unfortunately cleaning did not bring them back.
I ended up covering the carbon pills with two coats of silver-colored paint
which is made just for this purpose.   That fixed it.   Maybe you will be luckier.

Do you think the ghosting is somehow the old note persisting longer than it 
should?   If you play the first note, then wait before playing the second,
does it go away.

The arpeggiator is just sw in the mcu that is cycling through the notes.
Not sure how it would affect the pitch of an oscillator.   Of course one of 
the arpeggiator settings is to play the same notes an octave higher.

    Bob

  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Thursday, May 7, 2015 7:37 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
Right. So hold is working (ha). I'm used to mono synths where the next key pushed changes rather than adds the next pitch - as in the unison selection on the polysix). So all is good. Thanks
I replaced a few more button switches tonight.
The arpeggiator is working. (however I have the below mentioned issue still)

I still have issues. I tuned the 6th oscillator (trim 10 and 11). It seems fine. However when I add the octave lower (or second octave) it seems to push the 6th oscillator higher an octave. Arpeggiator also sends the 6th oscillator an octave higher. 
The other issue I have is when I play a low note then a high note I get a ghosting (like an extra pitch with pulsing) for a few hits of the high note. If I continue to repeat hitting the high note, the ghosting (for want of a better word) disappears and the pitch becomes clean. This can happen on any oscillator. 
The same happens in reverse: hit a high key then a low key, the same ghosting occurs for a while. 
I will clean up the key bed on the weekend as I'm working with about 60 percent of my keys.
Thanks again. I will fire up the oscilloscope again over the weekend



    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-07 by mpe1969@tpg.com.au

      
I just did another check. The arpeggiator is working correctly. The reason why it was jumping up an octave on oscillator 6 was because I had the 'add lower octave' switch turned on. Which lifts the 6th oscillator an octave rather than add a lower one. With the octave switch turned off, all 6 oscillators play the same note. (phew)

Ghosting: when the poly is turned on, the ghosting is there for the first few hits. Waiting for a period of time between hits doesn't influence its behaviour (still present once the key is hit). 
I did a quick experiment. First hit. The note had a fast beating, hit again a slow beating (more like a slow phase), push again a fast beating, hit again, then back to normal. (approx)
When using the arp the notes has the same behaviour e.g. the first few repetitions distorted/beating then normal. Once the note is sounding normal it stays like this until I hit another key. The note next to it can cause the same problem
Initially I thought it was the previous note causing the beating. but I'm not so sure now as the beating/ghosting seems to change with each consecutive hit until it seems to resolve.....

I will connect the oscilloscope tomorrow night and trace the oscillator wave (see if I can find where the ghosting is introduced)
Thanks again


    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-08 by Bob Grieb

      
The poly six may assign the same note to the same voice if it's played again after releasing the key.
Lots of synths work this way.

So it may be that the first time it assigns the note the pitch is off, then the second time it's closer,
then the third time it's better, etc.

If that matches what you are seeing, then maybe this time it would be the 4051 that charges the 
S&H caps for each oscillator.   If that chip has too much resistance, then the cap would not fully
charge the first time the key is assigned.  The cap voltage would get better after the second assignment, 
and even better after the third.   That's the only thing I can think of that sort of matches what
you are describing.   The key MCU and DAC should put out the same voltage every time you 
press a particular key.

BTW, if you put your scope on the S&H hold cap at the output of the 4051, it will probably
load it down enough to mess things up.   You may want to simply change the 4051 and see 
if that fixes it.   Or use the scope to debug the problem some more first. 

   Good luck.
 

  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Thursday, May 7, 2015 9:05 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
I just did another check. The arpeggiator is working correctly. The reason why it was jumping up an octave on oscillator 6 was because I had the 'add lower octave' switch turned on. Which lifts the 6th oscillator an octave rather than add a lower one. With the octave switch turned off, all 6 oscillators play the same note. (phew)

Ghosting: when the poly is turned on, the ghosting is there for the first few hits. Waiting for a period of time between hits doesn't influence its behaviour (still present once the key is hit). 
I did a quick experiment. First hit. The note had a fast beating, hit again a slow beating (more like a slow phase), push again a fast beating, hit again, then back to normal. (approx)
When using the arp the notes has the same behaviour e.g. the first few repetitions distorted/beating then normal. Once the note is sounding normal it stays like this until I hit another key. The note next to it can cause the same problem
Initially I thought it was the previous note causing the beating. but I'm not so sure now as the beating/ghosting seems to change with each consecutive hit until it seems to resolve.....

I will connect the oscilloscope tomorrow night and trace the oscillator wave (see if I can find where the ghosting is introduced)
Thanks again



    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-08 by Tubbutec

      

  
  
    Hi,

    the Polysix assignes the voices in a rotary order. It always chooses
    the next voice.

    

    After you turn on the Polysix it needs a couple of seconds until the
    expo converter is self-calibrated. It is absolutely normal that the
    pitches are way off during this time.

    

    You may also perceive 'popping' sounds the first few key presses
    because of the built in AGC in the effect section. 

    

    
Am 08.05.2015 um 05:24 schrieb Bob
      Grieb bobgrieb@yahoo.com [PolySix]:

    

    
 
  
      
          

            

              
The poly six may
                assign the same note to the same voice if it's played
                again after releasing the key.

              
Lots of synths
                work this way.

              


              

              
So it may be
                that the first time it assigns the note the pitch is
                off, then the second time it's closer,

              
then
                the third time it's better, etc.

              


              

              
If
                that matches what you are seeing, then maybe this time
                it would be the 4051 that charges the 

              

              
S&H
                caps for each oscillator.   If that chip has too much
                resistance, then the cap would not fully

              
charge
                the first time the key is assigned.  The cap voltage
                would get better after the second assignment, 

              

              
and
                even better after the third.   That's the only thing I
                can think of that sort of matches what

              
you
                are describing.   The key MCU and DAC should put out the
                same voltage every time you 

              

              
press
                a particular key.

              


              

              
BTW, if you put your scope on the S&H
                hold cap at the output of the 4051, it will probably

              
load
                it down enough to mess things up.   You may want to
                simply change the 4051 and see 

              

              
if that fixes it.   Or use the scope to
                debug the problem some more first. 

              

              


              

              
   Good luck.

              

              

              

              

                

                  

                      From:
                      "mpe1969@tpg.com.au [PolySix]"
                      <PolySix@yahoogroups.com>

                      To:
                      PolySix@yahoogroups.com 

                      Sent:
                      Thursday, May 7, 2015 9:05 AM

                      Subject:
                      Re: [PolySix] Re: Key assign mode issue

                     

                  


                    

                      

                         
                        

                          

                            

                              
I
                                just did another check. The arpeggiator
                                is working correctly. The reason why it
                                was jumping up an octave on oscillator 6
                                was because I had the 'add lower octave'
                                switch turned on. Which lifts the 6th
                                oscillator an octave rather than add a
                                lower one. With the octave switch turned
                                off, all 6 oscillators play the same
                                note. (phew)

                              


                              

                              
Ghosting:
                                when the poly is turned on, the ghosting
                                is there for the first few hits. Waiting
                                for a period of time between
                                  hits doesn't
                                  influence its behaviour (still present
                                  once the key is hit). 

                              
I did a
                                  quick experiment. First hit. The note
                                  had a fast beating, hit again a slow
                                  beating (more like a slow phase), push
                                  again a fast beating, hit again, then
                                  back to normal. (approx)

                              
When
                                using the arp the notes has the same
                                behaviour e.g. the first few repetitions
                                distorted/beating then normal. Once the
                                note is sounding normal it stays like
                                this until I hit another key. The note
                                next to it can cause the same problem

                              
Initially
                                I thought it was the previous note
                                causing the beating. but I'm not so sure
                                now as the beating/ghosting seems to
                                change with each consecutive hit until
                                it seems to resolve.....

                              


                                

                              
I
                                  will connect the oscilloscope tomorrow
                                  night and trace the oscillator wave
                                  (see if I can find where the ghosting
                                  is introduced)

                              

                              
Thanks
                                  again

                              


                              

                            

                          

                        

                      

                      

                      

                    

                  

                

              

            

          

          
      
      
    

    

    
-- 
http://tubbutec.de
https://www.facebook.com/tubbu.tec

  




    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-08 by mpe1969@tpg.com.au

      
Thanks . It isn't a start up issue (...though it starts on the first note). I was able to see the problem on the oscilloscope (see new photo). There is an arrow pointing to the trouble area. When distortion occurs this voltage still has not changed from the previous note. when the voltage finally moves (usually after a few key hits) the note sounds normal.
 It sounds like what you are mentioning Bob. However I get the same results on c39 and ic31 pin3. I have uploaded a painful 2 minutes of audio (folder polysix demo- distorted-korg polysix.mp3). using the arp to trigger notes (you'll get an idea of the problem after about 20secs). I figured it is easier to hear than me try to describe.
I'm happy to replace either or both ic's. Just thought it would be good to see what is happening.
Thanks again

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-08 by Bob Grieb

      
Are you sure the sound of the previous note that we hear is not coming from a different voice?
If the poly six does not re-assign the same voice for the same note, but always picks the next voice,
then maybe the issue is with voices not turning off fast enough when you release the key?
So you get the old note and the new note for a bit, then just the new note?

Maybe the sound is gated off, but the voice is still playing when it shouldn't be, then when you 
play a new note, the overall sound is gated on again, and you hear the new voice plus the old voice 
for a bit.   But this implies that you could wait longer between notes and the problem would 
go away.   You said that wasn't the case.

I think a simpler demo, with you pressing keys, and also telling us exactly what the sequence 
is, like press 1, release 1, press 2, etc.  might be more useful.  Unless the note is being re-assigned
to the same voice, my theory about the capacitor voltage doesn't work.

 Also, then you look at IC31 pin 3, you are seeing the voltages for all 5 voices, plus two or three
other voltages that are used to keep the anti-log tuned correctly.  Those extra levels are normal
and will not change as you play notes.

When you label your photos, please show the real vertical sensitivity, taking into account the probe.
So if the scope is set to 0.1V/div but you are using a 10:1 probe, then the setting is 1V/div, not 0.1V

   Bob



  
 
 


    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Friday, May 8, 2015 6:26 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
Thanks . It isn't a start up issue (...though it starts on the first note). I was able to see the problem on the oscilloscope (see new photo). There is an arrow pointing to the trouble area. When distortion occurs this voltage still has not changed from the previous note. when the voltage finally moves (usually after a few key hits) the note sounds normal.
 It sounds like what you are mentioning Bob. However I get the same results on c39 and ic31 pin3. I have uploaded a painful 2 minutes of audio (folder polysix demo- distorted-korg polysix.mp3). using the arp to trigger notes (you'll get an idea of the problem after about 20secs). I figured it is easier to hear than me try to describe.
I'm happy to replace either or both ic's. Just thought it would be good to see what is happening.
Thanks again


    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-09 by mpe1969@tpg.com.au

      
Thanks Bob. I have uploaded two new photos (which have the correct labelling - 2volts per cm) I am using a 10-1 probe. 
The good news is I have solved the problem!
I hope this makes sense. I watched the oscillator diodes. The distorted note always stopped when the sixth oscillator got to play the note. So then I would play a low note six times and then a higher note, which would be distorted until it reached to the sixth oscillator.
I took some photos of this distortion (probing resistor 149)
As mentioned in an earlier post, the sixth oscillator was also the one which lifted an octave rather than add a sub octave, when the sub octave was selected. I probed around the 4027 on osc 6 and it looked very different to what was happening on the other oscillators. (sending out a wave twice the frequency).
I put in a new 4027 today and it fixed both problems (the sub octave and the distortion)
I have uploaded a more basic sound demo- (you can count the 5 distorted notes then the clean 6)
sequence:
6 low 
5 distorted  high 
1 clean high
6 clean high 
repeated twice
And added some more photo's ( I realised afterwards that I still had the osilloscope set on dc......but it shows the problem at least
Thanks again to everyone for helping out. Thanks Bob for helping me understand my old oscilloscope a little better.
If anyone understands why a faulty 4027 would cause this effect, I'd love to know.

I will probably have other issues but if they are unrelated to the klm366, I will start a new thread.





    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-09 by Bob Grieb

      
Glad you got it sorted out.   Maybe the sub osc divider (4027) flip flops
were ignoring the signal that is supposed to shut them off, and running all 
the time on that voice?   Even so, you shouldn't hear it until that voice's
VCA opens up.

As the same note moves between the different voices in your demo, 
we can hear the pitch change a little.   I think if you tune up the voices
you can get them to be closer to each other than what you have right now.

The sub osc signal is a square wave, that is in sync with the osc for that
voice since it is clocked by it.   It's just summed in with the other waveform.

Bob



  
 
 
    From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Saturday, May 9, 2015 7:04 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
  
 


 




  



    

      
      
      
Thanks Bob. I have uploaded two new photos (which have the correct labelling - 2volts per cm) I am using a 10-1 probe. 
The good news is I have solved the problem!
I hope this makes sense. I watched the oscillator diodes. The distorted note always stopped when the sixth oscillator got to play the note. So then I would play a low note six times and then a higher note, which would be distorted until it reached to the sixth oscillator.
I took some photos of this distortion (probing resistor 149)
As mentioned in an earlier post, the sixth oscillator was also the one which lifted an octave rather than add a sub octave, when the sub octave was selected. I probed around the 4027 on osc 6 and it looked very different to what was happening on the other oscillators. (sending out a wave twice the frequency).
I put in a new 4027 today and it fixed both problems (the sub octave and the distortion)
I have uploaded a more basic sound demo- (you can count the 5 distorted notes then the clean 6)
sequence:
6 low 
5 distorted  high 
1 clean high
6 clean high 
repeated twice
And added some more photo's ( I realised afterwards that I still had the osilloscope set on dc......but it shows the problem at least
Thanks again to everyone for helping out. Thanks Bob for helping me understand my old oscilloscope a little better.
If anyone understands why a faulty 4027 would cause this effect, I'd love to know.

I will probably have other issues but if they are unrelated to the klm366, I will start a new thread.






    

     

    
    






 
 
  

    

    
    

      
Re: [PolySix] Re: Key assign mode issue

      
2015-05-14 by mpe1969@tpg.com.au

      
Well, I've cleaned up the keyboard bed (all keys working) but still have some issues.
I am having trouble tuning the poly. I am unable to get anything above an A sharp from C. I have tried v10 and 11.
I have also tried changing v2 but this will not get the voltage high enough (returned to original position).
ic18 has about -6.8 on pins 5  and 6 and about 3 volts on pin 7. Pin 7 on the oscilloscope looks pretty crazy.
I read an earlier post that someone had a damaged track that caused this problem, so will check out tracks again. Any advice appreciated.
Once again thanks
ps switch selection normal.