Discussion about the Korg PolySix synthesizer

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
> > >>
> > >
> > >
> > >
> > >
> > > ------------------------------------
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> >
>