Discussion about the Korg PolySix synthesizer

Hi Aniello,

If you are trying to set up Œinit clear¹ (reset) with the 56K resistor on
the test point on the power supply all the LEDS should come on without any
exceptions. You are basically setting the point where /REST on the CPU goes
low. Rotate too far and the output from the comparator is always low and
thus all the LEDs are lit in reset mode. If LEDs are changing from on to off
then I would suggest you have a problem with with data/PIO bus. Start at
connector CN10 and make sure the wiring from here to the KLM 371 (right-hand
top panel PCB) is all sound. If you have a logic probe or a scope you will
find this very usually for measure state on these lines and whether you have
connectivity. If this is a acid damaged repaired 367, then go back and take
a look at track continuity around where the old battery used to be, around
IC30/31 and even under the CPU socket. This is a favourite place for unseen
acid damage to lurk!

I would strongly suggest you look at these problem first before you attend
to the MG issues.  IC21 and IC16 (or parts of) form an astable with part of
a a timing constant in C19. However, don¹t forget that IC21 is a
transconductance amplifier and is controlled by a current on pin 16. So you
should also test the controlling circuitry from the demultiplexor downwards,
as well!

Cheers,
Andy 

On 08/07/2010 16:28, "aniello iaccarino" <ani.bliss@gmail.com> wrote:

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> Hi Andy
> I'm working on the original KLM367 board.
> 
> Cheers
> Aniello
> 
> --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Andrew
> Jury <andy@...> wrote:
>> >
>> > Are you working on an original KLM-367 or trying to calibrate the clone
>> > board?
>> > 
>> > Cheers,
>> > Andy
>> > 
>> > 
>> > On 05/07/2010 22:26, "aniello.iaccarino" <ani.bliss@...> wrote:
>> > 
>>> > >  
>>> > >  
>>> > >  
>>> > >    
>>> > > 
>>> > > Hi Friends
>>> > > I recently did the adjustment procedure and I found two problems.
>>> > > 
>>> > > The first is: not all the leds BANK A-D, PROGRAMS 1-8, MANUAL and TAPE
>>> > > ENABLE lights up when i turn VR1 from left to right, but every time I
>>> > > pass a certain point of VR1 leds light up in different combinations.
>>> > > [[-(]
>>> > > 
>>> > > I have to say that I can proceed to the calibration procedure anyway.
>>> > > But I don't know If the result of the calibration procedure  could be
>>> > > better if all leds light up instead some of them.
>>> > > 
>>> > > The second i found is that when I regulate MG speed I can't obtain a
>>> > > cycle of 10-40 sec, but just 4 sec,  a very short cycle.  [[-(]
>>> > > For this problem have I to check IC21 and C19?
>>> > > 
>>> > > Any suggestion?  [:D]
>>> > > 
>>> > > Thanks
>>> > > 
>>> > > Aniello
>>> > > 
>>> > > [Non-text portions of this message have been removed]
>>> > > 
>>> > >  
>>> > >    
>>> > > 
>>> > > 
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>> > [Non-text portions of this message have been removed]
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