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K2 - noisy AF & RF Gain Controls

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wd8rif

K2 - noisy AF & RF Gain Controls

Good day.

My Revision A K2 has noisy AF and RF gain pots. More precisely, turning
the AF gain pot produces scratchy audio and the turning the RF gain pot
causes the audio to drop out momentarily.

I've heard that the sort of behavior I'm seeing/hearing with the AF gain
pot isn't necessarily caused by a faulty pot; if this is the case, which
mod should I install before I think about replacing the pot?

Is the RF gain issue probably due to a failing pot?

Tnx es 73,

Eric, WD8RIF
http://home.frognet.net/~mcfadden/wd8rif/radio.htm

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Don Wilhelm-4

Re: K2 - noisy AF & RF Gain Controls

Eric,

Yes, the most likely problem is a faulty pot on both the AF Gain and the
RF Gain.
You are probably referring to mention of the Alternate AF Gain Wiring
Mod. If your K2 serial number is greater than 3000, it is already
installed, but if your serial number is below that, you should change
the wiring of the AF Gain control.

That wiring change reduces the DC current flowing through the pot - and
that wiring change will *not* cure an already noisy pot, but it will
keep a good pot in good condition longer.

73,
Don W3FPR

On 1/19/2012 10:04 AM, William Eric McFadden wrote:

> Good day.
>
> My Revision A K2 has noisy AF and RF gain pots. More precisely, turning
> the AF gain pot produces scratchy audio and the turning the RF gain pot
> causes the audio to drop out momentarily.
>
> I've heard that the sort of behavior I'm seeing/hearing with the AF gain
> pot isn't necessarily caused by a faulty pot; if this is the case, which
> mod should I install before I think about replacing the pot?
>

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wd8rif

Re: K2 - noisy AF & RF Gain Controls

Hello, Don.

Thanks for the quick reply.

I will open my K2--which is well below S/N 3000 and which wasn't built by
me--and determine if the Alternate AF Gain Wiring Mod has already been
performed. I will also order the two pots and install them when I perform
the mod.

I was happy to see in the reply from K2XT that the pots aren't
expensive--thanks, Rick.

Tnx es 73,

Eric, WD8RIF
http://home.frognet.net/~mcfadden/wd8rif/radio.htm

> Yes, the most likely problem is a faulty pot on both the AF Gain and the
> RF Gain.
>
> You are probably referring to mention of the Alternate AF Gain Wiring
> Mod. If your K2 serial number is greater than 3000, it is already
> installed, but if your serial number is below that, you should change
> the wiring of the AF Gain control.
>
> That wiring change reduces the DC current flowing through the pot - and
> that wiring change will *not* cure an already noisy pot, but it will
> keep a good pot in good condition longer.