[Elecraft] Its not over yet, I've gone back to basic K2 troubleshooting and find i have what seems a massive loss through the variable Crystal filter ?

[Don Wilhelm]

Cliff,

When looking at the RF voltage after the IF filter, tune the K2 slowly 
while looking for the peak RF voltage at U12 pin 4.
You will not be able to see the IF amplifier saturation with diodes D40 
and D41 in place - that information is prior to the introduction of 
those diodes.

T7 should be with the green winding closest to the crystal filter, the 
red winding adjacent to pins 4 and 5 of U12.
Turn off the AGC (press PRE and REV buttons together) and see if the 
audio level comes up.
You should have more RF voltage at U12 pin 8 than you do at U12 pin 4.

73,
Don W3FPR

On 1/29/2013 8:21 PM, Clifford Hynds wrote:
> Still having issues with my K2,
>
> I did align the filters using the Spectrogram software so I believe they
> are ok
>
> Well I decided to start from scratch and started RX troubleshooting/signal
> tracing  before I go back to TX side want to make sure the RX is 100% and
> while the stages up to the input of the crystal filter look ok the output
> compared to the manual is extremely low.
>
> I ended up using the RF probe supplied in the kit so all is known.
>
> Also removed the SSB board and fitted the corresponding jumpers at W2 and
> W3 and C167
>
> Here is what i am seeing with a 0.14Vrms input to the antenna  I used
> 10.1Mhz but I tried other bands with similar results.
>
> All voltages up to the input of the variable crystal filter look normal.
>
> Case or collector of Q22 = 2.3Vrms
>
> At W2 = ~ 2Vrms
>
> cathode D30 =0.89Vrms
>
> cathode D31 =0.95Vrms
>
> cathode D32 =0.757Vrms
>
> cathode D33 =0.767Vrms
>
> cathode D34 =0.735Vrms
>
> W3 = 0.080Vrms  the K2 book on Page 11 says it should be about 0.34Vrms , I
> am way low compared to that.
>
> I suspect either D34 or T7 ?
>
> Also I don't appear to be able to saturate IF amp it says I should read
> approx 0.15Vrms at Pin 8 of U12
>
> Am I on the right track.
>
> Thanks again,
> Cliff VK2CCJ
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