Hi Ingo

> is it a simple modification soldering is not one
> of my biggest strengths ;-)

Yes, quite simple.

From the center connector of the poti (=slider) a resistor leads to the
mixing point. The less the resistor the wider is the range of the poti.

As far as I remember the value is 1 Megaohm for the coarse.
You do not have to remove the existing resistor. Simply add a resistor
with lower value parallel to the existing resistor.

I added an 220kOhm resistor for the coarse tune. The value for fine tune
I do not remember at the moment.






Further explanations:


PP=Poti
Ra=existing Resistor
Rb=new Resistor


Before:

----PP
PP
PP<----RaRaRa-----
PP
----PP


After:

----PP
PP
PP<--+-RaRaRa-+---
PP | |
----PP +-RbRbRb-+



R'a and R'b appear electrical like one Resistor R'eff.


The new value can be determined by the following formula:

R'eff = R'a * R'b / (R'a + R'b)

Where is:
R'a is the existing resistor
R'b is the new add on resistor
R'eff is the resulting value



Example:
Old resistor=1Megohm
New resistor=1Megohm

1*1/(1+1) = 1/2 = 0,5

So the resulting value is 0,5Megaohm. This would double the range of the
poti.


Florian