Discussion about the Korg PolySix synthesizer

Hi,

I am afraid I cannot help you with the noise remotely. The Polysix is
quite noisy. Most of it comes from the BBD circuits of the KLM-368
board. You might take the signal directly from CN14 of KLM-366. This
is the pure synthesizer signal, before going through the KLM-368
effects board.

ARP:
It might be that ARP On/Off button does not work. You could try with
the lid open to make a temporary short across the button contacts
with a pair of pliers or a wire. These buttons wear out.

Good luck!

Johannes


On 2012-12-05 18:57, Arp Duex wrote:
> see comments.
>
>
> ________________________________
>   From: Johannes Hausensteiner <johau@gmx.net>
> To: PolySix@yahoogroups.com
> Sent: Wednesday, December 5, 2012 7:24 PM
> Subject: Re: [PolySix] Re: klm 367 board
>
>
>
> Hi,
>
> 1) Noise:
> - Does the noise change after you play (a) key(s)?
> - I have seen somewhere instructions for making an electric shield
> between the KLM-368 and KLM-369 boards. Maybe this woiuld help.
>
>
> //nope.. noise is there.. disapearing and reapearing in no regular
> fashion. at least i could determine any pattern.
>
> 2) Arpeggiator:
> - How does it behave when you are saying "it is dead"?
> - Does the ARP On/Off button LED work as expected?
> - Does the LED flash according to the speed setting?
> - The ARP trigger signal is routed through the rear panel "ARP Trig In"
> jack. This is a "normalized" jack, maybe the contacts are dirty; or
> one of the connections is bad on KLM-366, KLM-371.
>
>
> // led is flashing but when hittin the arp button it remains off.
> i'll check the jack.
>
> Good luck!
>
> Johannes
>
> On 2012-12-05 15:33, Arp Duex wrote:
>> Hi,
>>
>>
>> Yes. Found the guidelines for calibrating them. The noise on output puzzles me. Sometimes appear / sometimes disappear for no apparent reason.
>>
>> Arpegiator still dead.
>>
>>
>> I will continue the troubleshooting tommrow. Now I need a beer.
>>
>>
>> Thanks guys
>> Razvan
>>
>>
>>
>> ________________________________
>>    From: tonezone020 <swamp.gigs@googlemail.com>
>> To: PolySix@yahoogroups.com
>> Sent: Wednesday, December 5, 2012 4:06 PM
>> Subject: [PolySix] Re: klm 367 board
>>
>>
>>
>> Hi,
>>
>> Guidelines for calibrating each voice are in the service manual...
>>
>> T
>>
>> --- In PolySix@yahoogroups.com, "arpm234" <arpm234@...> wrote:
>>>
>>> Hey Johannes,
>>>
>>> Thanks a lot for the ideas. I've tested this morning the RESET signal of the main cpu and whatever i did, there were constantly 4.6 v there so by following the schematics I noticed it linked to the comparator IC5, LM393 which was bad in a way that pin 7 (output) and pin 8 (vcc) were internally shorted.
>>>
>>> Replaced that and everything came to live. Including keyboard and tones.
>>>
>>> NOW, There are still things to figure out.
>>>
>>> 1. Arpeggiator not working.
>>> 2. There is a noise around 22khz at output, like a self resonant thing like an old tube while functioning or like a camera flash when charging. very annoying.
>>> 3. each and every voice may need calibrating as each one is different in volume, pitch or filter. are there any guidelines for this?
>>>
>>> thanks again.
>>>
>>> Razvan
>>>
>>> --- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@> wrote:
>>>>
>>>> Hi Razvan,
>>>>
>>>> I think there are two different problemes:
>>>> - KLM367 CPU not starting
>>>> - KLM366 Key Assigner behaving wierd
>>>>
>>>> First thing ist to make the KLM-367 CPU start reliable. Check the power
>>>> supply for correct voltages and perform the reset circuit adjustment
>>>> procedure given in the service manual.
>>>> The test pulse at TP4 *is* in 20msec intervals. The pulse itself is
>>>> very short.
>>>> Check the resonator frequency at IC22 (CPU) pin 3. It should be ca 6MHz.
>>>>
>>>> Second: The KLM-366 has a test mode as well. "It is started by jumpering
>>>> pins DB7 and P17 using a diode (cathode towards DB7) on the 8049
>>>> processor on the KLM-366 circuit board (this can be done on the
>>>> keyboard connector CN04). In this mode the CV DAC is set to generate
>>>> 0V, 2.5V, or 5V depending on the position of the OCTAVE switch (16'
>>>> results in 0V, etc.)".
>>>> You can check this voltage at KLM366/IC9/pin1.
>>>> Check the reset signal. KLM-366 is in reset when switching to Tape
>>>> Interface mode. Check the resonator frequency. It should be like on
>>>> KLM-367 6MHz at CPU pin 3.
>>>>
>>>> Do the buttons behave normally? (Porbably not...)
>>>> The BANK, MANUAL, and PROGRAM buttons operate on the KLM-367 Programmer
>>>> CPU, whereas the ARP, HOLD, UNISON, CHORD MEM, and POLY buttons operate
>>>> on the KLM-366 CPU.
>>>>
>>>> Good luck,
>>>>
>>>> Johannes
>>>>
>>>>
>>>>
>>>> On 2012-12-04 20:27, arpm234 wrote:
>>>>> nobody ?
>>>>>
>>>>> --- In PolySix@yahoogroups.com, "arpm234" <arpm234@> wrote:
>>>>>>
>>>>>> Hello,
>>>>>>
>>>>>> I've did some tests today and here;s what i found:
>>>>>>
>>>>>> TO CONFIRM: cpu seems to be working fine since i was able to see the clock on TP4 on osciloscope. Strege thing that somebody mentioned the gap should be 20 ms and i meassured 10ms. Is this ok ?  Also the TP2 spot looks ok - The multiplexed signal from the pots it is there.
>>>>>>
>>>>>> PROBLEM: there cpu starts randomnly. A few power off - power on cycles are necesary to get the clock there. I this this is related of the bad 4 x 74ls75 found on the control panel board. Two of these latches seem to be dead.
>>>>>>
>>>>>> PROBLEM: Altoought there is sound presend, and lfo, cutoff, and all the other pots are working, the sound is non interupted, very loud and at a rather high pitch. voice 6, 5, 4 diode leds are light up, and the sound resemnbles like a few vco beeing active. the other 3 leds, for voice 1, 2, 3 are off. touching the keyboard changes the pitch slighly but then resumes the state before. I'm suspecting the latches: 74ls75
>>>>>>
>>>>>> QUESTION: how to test the key assigner cpu ? Is there a method simillar to the uC found on KLM 367 ?
>>>>>>
>>>>>> Thanks for support guys.
>>>>>>
>>>>>> Razvan
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
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