It sounds like you may need a new pot as well.
The mod cures the need to have the Audio Gain right near the minimum stop to
turn the audio way down. In the original circuit, the audio pot acts as a
shunt across the audio line. That works as long as the minimum resistance of
the pot is very close to zero ohms. Most pots are not designed to provide
very close to zero ohms at the minimum reliably over time. A tiny amount of
wear, dust, etc., will raise the minimum resistance a few ohms and suddenly
the pot is scratchy and erratic near the minimum.
The mod fixes that by wiring the pot like most audio gain controls. The mod
provides a logarithmic control response that spreads out the lower volume
gain control range over a much larger portion at the "low" end of the pot so
the volume is essentially zero before you get to the minimum stop. Also,
you'll find that the "action" of the pot feels more 'normal', since the
change in volume as you rotate the pot will be more like other volume
controls.
If you have zones of erratic behavior other than close to the minimum
setting, you probably have a worn or dirty pot.
Of course, the mod only affects how the audio gain control operates. It does
not reduce the maximum gain available at all (nor does it increase the
maximum gain available).
Ron AC7AC
-----Original Message-----
K2 #2636 has finally developed enough irregular operation of the audio gain
pot that I'll be doing the AF gain pot mod soon. It's become so erratic
that I'm wondering if I should actually install a new pot at the same time.
As I rotate the knob, there are some zones that sound quiet, then suddenly
very loud with only slight movement. Will the mod cure this, or should I
change the pot at the same time?
Parker WD8JOL
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