Hi Florian,
Your information is valuable !!!!!!!!

Thank you very very much.

I will follow your steps tomorrow morning, as I think you have almost explained me everything. I will also tune the VCO4 as you described, (the simple way to change the offset with VR402).

--- In korg_mono-poly@yahoogroups.com , Florian Anwander <fanwander@...> wrote:
>
> 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
>