Still need help with K6XX CW Tuning Indicator on K1

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Still need help with K6XX CW Tuning Indicator on K1

George Averill
All,

I feel like I’m trying to perform brain surgery with a pocket knife.  All of my test equipment is as ancient as I am. HI  Where did all the tubes go?

The first kit didn’t work so I have ordered another one.  That should solve the problem if the problem is the IC in the kit.  I will also try to take more time soldering the surface mount components this time.

What really puzzles me is that, with the kit out of the circuit, and using a scope, I have never been able to pull a 600 Hz  sidetone signal off the side of the volume control, but I can off the speaker.  I’m positive that the wire to the volume control is OK, and it’s connected to AF1 at the volume control coming from the AF Preamp.  It’s also connected as per the instructions that came with the kit.

Any help or suggestions would be appreciated.

73, George, K4EOR

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Re: Still need help with K6XX CW Tuning Indicator on K1

Don Wilhelm-4
George,

The sidetone comes into the AF2 (wiper) connection to the AF gain
control, try there with your 'scope.  You might see it at AF1, but that
depends on the position of the AF Gain - at normal AF Gain settings it
may be too small there for the amplitude setting of your 'scope.

As for the K6XX CW indicator functioning - and since you do have a
'scope - then once you can power up the indicator board, look for an
audio signal between ground and either side of the capacitor to the left
of the tuning pot (the cap above the IC).  You should find a sawtooth
signal there.  If you want to pre-adjust the frequency of the indicator,
adjust the pot until you have the frequency of that waveform at your
desired sidetone pitch.  I use a frequency counter, but you can use a
'scope with some arithmetic based on the horizontal time base setting of
your 'scope.

73,
Don W3FPR

On 2/15/2015 5:46 PM, George Averill wrote:
> All,
>
> I feel like I’m trying to perform brain surgery with a pocket knife.  All of my test equipment is as ancient as I am. HI  Where did all the tubes go?
>
> The first kit didn’t work so I have ordered another one.  That should solve the problem if the problem is the IC in the kit.  I will also try to take more time soldering the surface mount components this time.
>
> What really puzzles me is that, with the kit out of the circuit, and using a scope, I have never been able to pull a 600 Hz  sidetone signal off the side of the volume control, but I can off the speaker.  I’m positive that the wire to the volume control is OK, and it’s connected to AF1 at the volume control coming from the AF Preamp.  It’s also connected as per the instructions that came with the kit.
>
>

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