[Elecraft] K2 Distorted receive audio and low power output

[Don Wilhelm]

Denis,

Do you have the KDSP2 installed in your K2?  If so, check the DSP NR. 
If it is on, it can cause distortion.  It does an effective job of 
reducing noise, but does introduce some distortion - and may appear 
intermittent depending on the signals and their level.

If no KDSP2, then check the soldering in the PLL Reference area as well 
as the BFO area.  Marginal solder connections may have been OK in the 
past, but can fail after time.  Check the schematic for components in 
those areas and re-flow the soldering.

You can also do the Receive Signal Tracing as indicated in the manual. 
You may have to connect a strong signal generator as described in the 
Troubleshooting section of the manual.  An XG1 or XG2 will not provide a 
strong enough signal (the XG3 will), so construct the oscillator shown 
in the troubleshooting section of the manual.

The power output problem may or may not be related.  The best way to 
find the offending stage is to do Transmit Signal Tracing as described 
in the Troubleshooting manual appendix.  When you get to a stage which 
produces less than the expected values, that is the output of the 
failing stage, and you can investigate that particular stage for the 
problem.  Re-flowing the soldering may correct it.
Component failure is not the most common cause of failure (soldering 
is), so do not jump to conclusions about a component being bad - 
exception is if one of the PA transistors has been damaged.  If you find 
everything up to the PA transistor bases OK, then replacement of the PA 
transistors with the K2PAKIT from Elecraft may be in order.

73,
Don W3FPR

On 4/26/2017 5:19 PM, Denis Jackson wrote:
> My K2 hasn't been used for a few years but, with the intention of taking it
> out for a bit of SOTA work, I powered it up today.  Alas, I have a problem.
> 
> The receive audio is intermittently distorted on all modes.  With a constant
> carrier, it sounds like there is a warble to the note.  There is another
> problem in that it has is that the RF power output is only about 6 watts
> (it's the 15W version) and that seems constant on all bands.  I don't think
> these two problems are related because the power is always low regardless of
> whether the audio is distorted or not but thought it worth mentioning
> nonetheless