Korg Mono/Poly

Hello

Am 09.03.2012 14:24, schrieb dir_marillion:
 > Is the TL072CP under the capacitors (inside the circle) ?
Yes. There are two, but the one which affects VCO4 is under the second
bentover capacitor (counted from the bottom of the circle).


 > Do you suggest to replace the TL072 or I may have a damaged 4006 ?
There is a basic principle of search for faults: never change two things
in the same step.

So the order of steps should be:
* Replace IC10 (TL072)
* Check the portamento of voice 4
* If it does not work: check the fourfolded portamento potentiometer, in
case of doubt shortcut in each layer of the potentiometer the two outer
contacts
* Check the portamento of voice 4
* If it does not work: insert a cable into the portamento socket (this
switches the 4066).
* Check the portamento of voice 4



 > Second question. As VC04 is also detuned about 4 notes and I do not
 > have the KLM398, which are the switches for the 4rth VCO that I have
 > to tune ? I show two white circle tuners under the fourth VCO (check
 > my uploaded picture).
You don't need KLM398, but only KLM354. I described the tuning procedure 
in detail at http://fa.utfs.org/diy/korg_monopoly/vco_adjustment.html
I would NOT do the full procedure, but simply try to change the offset 
with VR402
See 
http://fa.utfs.org/diy/korg_monopoly/mp_16_klm_354_layout_TRIMMERS.jpg 
the most left light green marking at the bottom named with "tune offset"

Florian