Discussion about the Korg PolySix synthesizer

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.

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.

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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>>>>
>>>>
>>>>
>>>>
>>>
>>
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