Discussion about the Korg PolySix synthesizer

Hi,

So the preset thing is clear; probably a "genius" cranked the trimpots
and made the sounds unusable.

For the distortion: try to find out on what this depends. I would start
with a simple setting (e.g.only VCO-1, filter all open, "gate" EG, etc.)
Then play around with single parameters and notice under when the
distortion/modulation starts. Maybe you can find out this way where
is comes from.
Further check whether it is on all 8 voices. If yes, then probably the
reason is in a common part (e.g. overall synth gain circuit, ...)

Voice #6: check IC9 of unit #6. On pin1 there should be the VCO-2
waveform regardless of On/Off setting on the control panel. IC9/pin13
is the control signal, it should be high when VCO-2 is on, low when
off. IC9/pin2 is the switched VCO-2 wave.

Good luck!

Johannes



stagerhodes wrote:
> ok...i think i made some progress here...when trying to adjust VR27 
> in the presets board (with piano 1 , as Johannes told) suddenly i 
> heard the sound loud and clean...after a bit the distortion came 
> again...well, in this process when it sounded ok i changed from 
> piano 1 to manual and the synth was there without 
> distortion...but...no VCF working (just the FINE Cutoff was 
> working)...so i believe my problem is related with the filter...i 
> will do more testing here, in the mean time if someone can give some 
> clues based on this it would be great..thanks to all ! 
> Oh..almost forgot...i found the VCO 2 not working in the voice #6. 
>  
> 
> --- In PolySix@yahoogroups.com, "gil_we" <gil_we@...> wrote:
> 
>>Also, can you see any broken or "cold" solder joint on this board ? 
>> 
>>
>>--- In PolySix@yahoogroups.com, "gil_we" <gil_we@> wrote:
>>
>>>The Flanger board (KLM-291) is also the mixer board, in case it got  
>>>defective it makes sense to me that the synth problem may be related  
>>>to a defect on that board as well. 
>>> 
>>>Do you get that problem only, but only for the synth sound ? 
>>> 
>>>Does it sound distorted on both VCOs ? You can eliminte VCO1 and only  
>>>listen to VCO2 and vice versa ?
>>> 
>>> 
>>>--- In PolySix@yahoogroups.com, "stagerhodes" <stagerhodes@> wrote:
>>> 
>>>>thank you !...well, the controls are working, only it makes a kind of  
>>>>distortion which is more audible in the 16' and 8' octaves, it  
>>>>reduces it in the 4' ( a distortion with some kind of modulation ),  
>>>>the bad effect will be more noticed too if one set the EG Intensity  
>>>>to center or full counterclockwise (negative envelope). I tried to  
>>>>memorize 2 patches and the programmer seems ok, the patches are 
>>>>there, so i just don't know what to do next... 
>>>>I must say that it seems the top panel was (may be the unit crashed  
>>>>in the floor or something) bend in the master tune pot area, after a  
>>>>close look i saw one of the screws fixing the Flanger board , in its  
>>>>place with a small PCB fragment attached, and the board broke in one  
>>>>of its edges (screw area). I took out the flanger board and it seems  
>>>>no damage in any of the pcb traces...anyway does any malfunction in  
>>>>this board reflects in the synth section sound (with flanger turned  
>>>>off) ?? 
>>>>Oh, the preset sounds are not ok, just a short beep (low frequency),  
>>>>the strings and brass are OK 
>>>>regards 
>>>>Art
>>>> 
>>>> 
>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@...> wrote:
>>>>
>>>>>The PCB looks OK; no damage due to leaked battery as in the Polysix 
>>>>>is visible.  According to the pics (silkscreen) the battery which is 
>>>>>mounted seems to be original or genuine replacement.  So I  would not 
>>>>>suspect a threat like in the P6.  It largely depends on the battery 
>>>>>make, which seems to be good quality in this unit. So as long as the 
>>>>>battery retains sufficient voltage (more than 2.5V) I would not 
>>>>>worry about it. 
>>>>>This does not surprise me, since the Trident MK I programmer and the 
>>>>>MK II programmer are completely different. MK I was designed before 
>>>>>Polysix, MK II afterwards or the same time obviously using the same 
>>>>>technique in both (edit mode, etc). Amazingly they did not use a 
>>>>>microprocessor for the patch manager in the MK I but an all-hardware 
>>>>>type of design. 
>>>>> 
>>>>>Regarding your original problem: it may be (even likely) that the 
>>>>>battery is dead or at least discharged and all memory patches are gone 
>>>>>producing no or meaningless sound. Are the knobs and switches working 
>>>>>in "Manual" mode? How do the presets ("Piano 1", "Piano 2", "Clav") sound? 
>>>>> 
>>>>>According to the schematics there are on KLM-317 three sets of pots 
>>>>>for the presets; you may set your favourite sound patches there. 
>>>>>(The Yamaha CS-60 and CS-80 had a similar kind of "Patch Memory"..) 
>>>>> 
>>>>>Johannes
>>>>> 
>>>>> 
>>>>>stagerhodes wrote:
>>>>>
>>>>>>Hi, 
>>>>>>just uploaded 8 photos of the board, hope they're ok now for you to  
>>>>>>try to help me. 
>>>>>>regards, 
>>>>>>Art
>>>>>>
>>>>>> 
>>>>>>--- In PolySix@yahoogroups.com, "gil_we" <gil_we@> wrote:
>>>>>>
>>>>>>>you're welcome, 
>>>>>>>
>>>>>>>I'm interested to see how corroded is the board - if any at all.
>>>>>>> 
>>>>>>>
>>>>>>>--- In PolySix@yahoogroups.com, "stagerhodes" <stagerhodes@y...> wrote:
>>>>>>> 
>>>>>>>>Hi Gil, 
>>>>>>>>well, i'm not at home right now, but the battery is from Sanyo, and  
>>>>>>>>the big lettering is CADNICA (nickel cadmium). 
>>>>>>>>I will take better pictures tonight and post them (deleting the ones  
>>>>>>>>there now)...well, what can i say besides thank you for your 
>>>>>>>>support ...
>>>>>>>>
>>>>>>>>
>>>>>>>>--- In PolySix@yahoogroups.com, "gil_we" <gil_we@y...> wrote:
>>>>>>>> 
>>>>>>>>>It's very hard to see anything on those pictures... I do see though  
>>>>>>>>>that the battery was already replaced ?? looks like a lithium battery  
>>>>>>>>>what does it say on it ? 
>>>>>>>>>
>>>>>>>>>Try to provide close up high resolution pictures of the programmer
>>>>>>>>> 
>>>>>>>>>
>>>>>>>>>--- In PolySix@yahoogroups.com, "stagerhodes" <stagerhodes@y...> wrote:
>>>>>>>>> 
>>>>>>>>>>I think i have another problem here, not related with battery leak,  
>>>>>>>>>>i just uploaded some photos , not very good quality, but the battery  
>>>>>>>>>>seems to be sealed, and the programmer is working despite some press  
>>>>>>>>>>memory recall buttons need cleaning or replacing. Well , the synth  
>>>>>>>>>>sound has some distortion and sounds like ring modulation, this is  
>>>>>>>>>>minimized if the negative/positive VCF EG Intensity is full  
>>>>>>>>>>clockwise. The preset sounds are like no envelope sustain, just a  
>>>>>>>>>>short low (frequency) click...well, i'm not a keyboard technician, 
>>>>>>>>>>just trying to make something here, otherwise i will have to take 
>>>>>>>>>>the synth and schematics to a friend who is a technician (works in  
>>>>>>>>>>musical instruments, not vintage ones but...) and try to put this  
>>>>>>>>>>synth to play...have to say the brass and strings sections are ok,   
>>>>>>>>>>the split keyboard function switches and behavior are ok, bend and  
>>>>>>>>>>mod ok...well...lets see
>>>>>>>>>>
>>>>>>>>>> 
>>>>>>>>>>--- In PolySix@yahoogroups.com, "gil_we" <gil_we@y...> wrote:
>>>>>>>>>> 
>>>>>>>>>>>Thanks,  
>>>>>>>>>>> 
>>>>>>>>>>>I believe that this type of info should be shared all over the net.   
>>>>>>>>>>>The Trident's schematics are very rare - took me weeks to get them;  
>>>>>>>>>>>however, here they are.  
>>>>>>>>>>> 
>>>>>>>>>>>I got my Trident in disasterous condition, nothing worked, battery   
>>>>>>>>>>>corrosion, bad chips, everything you may think of... Got it work   
>>>>>>>>>>>finally after doing the refurbishment step by step. This is an   
>>>>>>>>>>>incredible machine, one of the best ever made and definately Korg's   
>>>>>>>>>>>best Polysynth.  
>>>>>>>>>>> 
>>>>>>>>>>>Let us know how you proceed, also if you can take some pictues of the   
>>>>>>>>>>>board it would help.
>>>>>>>>>>> 
>>>>>>>>>>> 
>>>>>>>>>>>--- In PolySix@yahoogroups.com, "stagerhodes" <stagerhodes@y...> wrote:
>>>>>>>>>>> 
>>>>>>>>>>>>Oh, i'm very pleased regarding this group , many thanks for your  
>>>>>>>>>>>>reply and the schematics beeing available for download...  i will  
>>>>>>>>>>>>unmount the Trident may be tonight or tomorrow night and will post my  
>>>>>>>>>>>>sights inside. This is one of my favorite (regarding it's wood design  
>>>>>>>>>>>>and the sound, particularly the synth section) keyboards from korg ,  
>>>>>>>>>>>>and i can say i tried almost them all at the time they were beeing  
>>>>>>>>>>>>produced since i was working demoing them in a shop. So now is the  
>>>>>>>>>>>>time for me to have some of them in full working condiction... 
>>>>>>>>>>>>Art
>>>>>>>>>>>> 
>>>>>>>>>>>> 
>>>>>>>>>>>>--- In PolySix@yahoogroups.com, "gil_we" <gil_we@y...> wrote:
>>>>>>>>>>>> 
>>>>>>>>>>>>>I didn't fully understand how the synth section acts on this machine... 
>>>>>>>>>>>>>Also, is there corrosion (green colored) on the battery and near it ? 
>>>>>>>>>>>>>Are there bad (black colored)traces ? are the signal and synth boards  
>>>>>>>>>>>>>correded as well on some areas ? 
>>>>>>>>>>>>> 
>>>>>>>>>>>>>Take extra care not to hurt anyting that works. Particually, stay  
>>>>>>>>>>>>>away from the 10 leg transistor type component at the bottom left  
>>>>>>>>>>>>>side of right bottom (signal) board. This one is extremely sensitive  
>>>>>>>>>>>>>to extreme temperature changes and is very rare and expensive to get. 
>>>>>>>>>>>>> 
>>>>>>>>>>>>>You can use the schematics I uploaded to the Files section.
>>>>>>>>>>>>> 
>>>>>>>>>>>>> 
>>>>>>>>>>>>>--- In PolySix@yahoogroups.com, "stagerhodes" <stagerhodes@y...> wrote:
>>>>>>>>>>>>> 
>>>>>>>>>>>>>>Hi, 
>>>>>>>>>>>>>>i just bought a Trident MK I in which the poly synth section is  
>>>>>>>>>>>>>>malfunctioning, i am almost certain that the problem is the battery  
>>>>>>>>>>>>>>question , and the leakage from it. It seems the tune is ok, all notes  
>>>>>>>>>>>>>>are sounding (brass and strings sections), in the synth section one can  
>>>>>>>>>>>>>>ear some sound (it is possible to ear the notes pitch, but with some  
>>>>>>>>>>>>>>strange effects in them) and the memory section is not working which  
>>>>>>>>>>>>>>leads me to the battery question. Is there any special care i must have  
>>>>>>>>>>>>>>in this model ? 
>>>>>>>>>>>>>>regards 
>>>>>>>>>>>>>>Art 
>>>>>>>>>>>>>>Portugal
>>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>> 
>>>>>>>>>>
>>>>>>>>> 
>>>>>>>>
>>>>>>> 
>>>>>>
>>>>>> 
>>>>>> 
>>>>>>PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6  
>>>>>>Yahoo! Groups Links 
>>>>>> 
>>>>>> 
>>>>> 
>>>>  
>>> 
>> 
> 
> 
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
> Yahoo! Groups Links
> 
> 
> 
>  
>