Discussion about the Korg PolySix synthesizer

When you get it all up and working, you will need to set the trimpots
on the KLM-367 board as described in the calibration steps.   Setting 
them in the same position as they were on the old board by eye 
is not really a good way to do it, since the other components in 
the circuit may have been replaced (new resistors from China).  So 
you need to re-do the calibration.   Usually the first step would be 
to set the supply voltages to their exact values, if you have a meter that you trust.
Of course, changing the voltages may require that you re-tune the voices,
but you should probably do that anyway.  I don't know when that was last 
done to your Poly Six.   If you have reason to think the 366 board trimmers
are fine as they are, then you should not change the power supply rails, 
as that could affect the settings.

    Bob

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On Sat, 2/13/16, jw_dewdney@yahoo.com [PolySix] <PolySix@yahoogroups.com> wrote:

 Subject: Re: [PolySix] Re: PROGRESS!!!!
 To: PolySix@yahoogroups.com
 Date: Saturday, February 13, 2016, 5:03 PM
 
       i checked them yes - many times - and the 5v was
 constantly at 4.96 and the 15 v at 14.92 or something - both
 seemed MORE than close enough... (?)
 
     
      
 
     
     
 
 
 
 #yiv0284512244 #yiv0284512244 --

Does anything change when you remove the resistor?

Try connecting your scope to the reset input to the CPU
and set it to auto trigger.  Connect the resistor.
Turn the trimmer to just light up everything.   You should
see RESETb low at that time.   Now remove the resistor.
You should see RESETb go high.  If all of that works, 
then the reset circuit is set properly and is working.

As to why you are not getting the proper LEDs when the CPU
is running, we can treat that as a separate issue if reset is
working properly.

   Bob

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On Mon, 2/15/16, jw_dewdney@yahoo.com [PolySix] <PolySix@yahoogroups.com> wrote:

 Subject: [PolySix] Re: Power supply voltages
 To: PolySix@yahoogroups.com
 Date: Monday, February 15, 2016, 1:00 AM
 
 
  
 
 
 
   
 
 
     
       
       
       SO - I'm back at it now - I proceeded to rig up
 something for the 56K resistor (47K + 9.1K) but when I
 adjust VR1 to JUST light things up and then disconnect the
 resistor- I don't get either Bank A OR Pgm 1 lighting
 up. What does that mean?? My voltage drop on the +5v supply
 is 0.25v.
 
     
      
 
     
     
 
 
 
 #yiv2370670852 #yiv2370670852 --

OK.   If the lights go on when you connect the resistor 
and off when you disconnect it, then no need to scope reset,
I guess.   Maybe start scoping some other signals to continue
your debug efforts.

    Bob


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On Mon, 2/15/16, jw_dewdney@yahoo.com [PolySix] <PolySix@yahoogroups.com> wrote:

 Subject: Re: [PolySix] Re: Power supply voltages
 To: PolySix@yahoogroups.com
 Date: Monday, February 15, 2016, 6:05 PM
 
 
  
 
 
 
   
 
 
     
       
       
       Hi Bob - I ASSUME it's working correctly (the
 reset) since the lights go off when I disconnect it. As
 previously mentioned I measure a 0.25v drop with the
 resistor in place across the +5v supply test point. As for
 the behaviour on the resetb pin- i will have to report to
 you later. Thanks!
 
     
      
 
     
     
 
 
 
 #yiv0777466308 #yiv0777466308 --