Discussion about the Korg PolySix synthesizer

It is normal for the Polysix to be extremely out of tune for the first few
seconds after it is powered on. I worked on one that seemed reasonably in
tune after about 5 seconds, and another that took almost 30 seconds before
it sounded decent. I believe that would be caused by the thermistors warming
up, not an optocoupler problem. Do the LEDs behave any differently if the
keyboard is unplugged from the 366 board?

Don B.

 

  _____  

From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf Of
Frank Carvalho
Sent: Tuesday, November 19, 2013 6:27 PM
To: PolySix@yahoogroups.com
Subject: Re: [PolySix] Weird assigner issue

 

  

No, something is wrong. It freaked while opening it up. After I unscrewed
the keyboard it got better, and seemed to act normal,  with all 6 Leds
coming on. But suddenly it jumps back into freak mode, where only Leds 1-4
light up. Here the missing keys are F1, F1#, C2#, D2 etc.

I can get it out of freak mode by switching it off and on, but it will fall
back into failure.

Btw, the optocoupler struggles initially to get the synth into tune. Could
it be straining something?

(Maybe I should get a VTL5C9 instead)?

Frank

 

 

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-------- Oprindelig meddelelse --------
Fra: Frank Carvalho <dko4342@vip.cybercity.dk> 
Dato: 
Til: PolySix@yahoogroups.com 
Emne: Re: [PolySix] Weird assigner issue 


  

Hi Johannes

Ok, so I turned it on to do the checks you mentioned, and everything now
sounded normal again! But after a few notes, it started to get weird again,
and then went back to normal. Tapping lightly on the left side of the panel
reveals that I have a bad connection somewhere. 
I have to open the synth again, and check for bad connections. Maybe a bad
soldering, as I recently replaced the optocoupler. Fortunately, I have to
say. That means that there is probably nothing fundamentally wrong with it.
I'll see if I can find the culprit.

Thanks so far

Frank

On 11/18/2013 11:16 PM, Johannes Hausensteiner wrote:

  

OK, so the keys that do not work are F#1, G1, D2, D#2, A#2, B2, F#3, G3,
D4, D#4, A#4, B4, F#5, and G5, correct?
When starting the arpeggiator (besides playing wrong notes) does it
light the small voice-LEDs on KLM-366?
When connecting a footswitch to the CHORD MEM footswitch jack, does the
CHORD MEM button LED work as expected (can be switched on and off by
footswitch)? Note: if you do not have a footswitch you can you a normal
phone cable and short the tip to the sleeve on the far end connector
with a paperclip or similar for a test.
And the HOLD button works?

From the noworking keys I would say the lines P16 and P17 are not
working correctly. But the buttons and the VCO control voltage should
work OK...

Try: disconnect CN12 from KLM-366 (this goes to KLM-371). Are the notes
in tune?

Johannes

On 18.11.2013 19:15, Frank Carvalho wrote:
>
>
> Poly/Chord/Uni do not seem to have any effect, and the LEDs don't come on.
> Hold is on when the synth is turned on, but can be turned off and on.
> Hold now lights up.
> If the keys are numbered repeatedly with 1 to 8, beginning with the
> lowest key, then it is every number 6 and 7 that is off.
> The arpeggiator sends repeated trig signals, but as the same note sounds
> every time, I cannot hear anything but the repetition. Actually the
> sound is much like a detuned unison mode.
>
> And, yes, I have an ancient Philips oscilloscope, if necessary.
>
> I certainly hope I can fix it. I love this synth.
>
> Oh, before anyone asks, I did the battery mod long ago, before any leaks
> occurred.
>
> Thanks
>
> /Frank
>
> On 11/18/2013 09:09 AM, Johannes Hausensteiner wrote:
>>
>> The issue is related to the KLM-366 Key Assigner CPU circuitry. Probably
>> two of the I/O lines are dead (remember, it is an 8bit CPU).
>> Which keys do work and which don't?
>> Do the key assigner buttons (POLY/UNI/CHORD/HOLD/ARP) work?
>> Does the arpeggiator don anything?
>>
>> Do you have access to an oscilloscope?
>>
>> This surely can be fixed!
>>
>> Johannes
>>
>
>
>