[Elecraft] K2 receiver problem

[Don Wilhelm]

Gerhardt,

It sounds like the AGC Threshold is not set properly.

I would proceed by first checking the alignment of the bandpass filters in
Transmit mode (at 2 watts) and then set the AGC Threshold for optimum
receiver sensitivity - with no antenna connected and AF and RF Gains set to
max, adjust for the highest voltage at Control Board U2 pin 5 which yields
no change in the audio noise when switching the AGC between OFF and ON.
That will usually result in a voltage in the range of 3.65 to 3.8 volts at
U2 pin 5.  Set the S-meter end points (CAL S Hi and CAL S-Lo) after setting
the threshold.

If that does not cure the problem, then look for a problem in the IF receive
chain - that will be where the signal tracing is required, follow the
p[rocedure for receiver signal tracing in the Troubleshooting appendix of
the K2 manual.


73,
Don W3FPR

> -----Original Message-----
>
> got a K2 from another OM on my workbench. It's got a
> receiver problem and I just want to make sure I do the
> checks in the correct order and I'm looking for hints,
> if available!
>
> Thanks in advance!
>
> So here's the problem and what I want to do. It seems
> the receiver runs with "handbrake on". So the s-meter
> shows 3 bars without an antenna but the rf gain is
> fully clockwise. I can reduce signals to zero (using
> RF gain) with this K2 which I can't using my own K2.
> So mine has a higher sensitivity.
>
> Any idea what's wrong?
>
> What I want to do:
> - s-meter alignment
> - I.F. amplifier alignment
> - (maybe band pass alignment)
> - signal tracing receiver and synthesizer
>
> Kind regards
>
> Gerhard
> DH3FAW
>