K2 Bad CW signal

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K2 Bad CW signal

Micha DF4WX
Dear community

I am having problems with my K2. I got complaints about a lousy signal (e.g. rst 591). When I checked my signal with an external RX I heard a kind of a noise instead of a clean CW signal. When I press the "Tune" button, I have a very clear tone (as usual) in the control-RX. With all power levels the PA current is the same both in tune and in normal CW TX-mode. Only the resulting signal is different.

What could be the root cause of this issue? Are the signal paths of CW-TX and tune different to each other?

Any hint is highly appreciated.

Best regards
Micha, DF4WX

K2 #7488 with all options installed
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Re: K2 Bad CW signal

Don Wilhelm
Micha,

The signal paths for TUNE and CW transmit are the same from the MCU outward.

However, I recently repaired a K2 with the same problem.  The problem
was traced (using a spectrum analyzer) to RF Board U4 in that particular
case.

However, your problem could be different - look at the keying waveshape
components first (Control Board U10A and Q8) as well as the PLL
Reference Oscillator.

73,
Don W3FPR

On 10/27/2017 2:47 AM, Micha DF4WX wrote:
> Dear community
>
> I am having problems with my K2. I got complaints about a lousy signal (e.g. rst 591). When I checked my signal with an external RX I heard a kind of a noise instead of a clean CW signal. When I press the "Tune" button, I have a very clear tone (as usual) in the control-RX. With all power levels the PA current is the same both in tune and in normal CW TX-mode. Only the resulting signal is different.
>
> What could be the root cause of this issue? Are the signal paths of CW-TX and tune different to each other?
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