First An Apology

[N0EHQ]

I would like to take an opportunity to offer an apology to all on the reflector for my rant of a week or so ago concerning my inability to get this K2 to work as it should. The rant was totally out of line. So with that being said I decided to take some time off from the K2 and come back when I was a whole lot less frustrated.

I do have the PLL reference oscillator in spec. Scott at Elecraft sent me a different PLL crystal, a 12mH inductor and replacements for D16 and D17. I replaced the crystal first and performed the range test. The crystal by itself moved the renge from 8.0 to 10.0. The addition of the 12mH inductor brought the range up to 12.4 which is pretty close to being in the middle of the spec.

Now I have been chasing the BFO range. The high end of the BFO range is 4918.2 which is quite a bit high from what the manual gives as an expectation (4916-4917). The low end of the range is 4914.8 which isn't even close to the expected range (4909-4912) as indicated in the manual. The resulting range is 3.4 which is too low. I have tried new crystals with virtually no change in range. L33 appears to be intact and constructed correctly in conjunction with R116. I even slipped a small piece of doubled over electrical tape between L33 and R116 to ensure that there were no shorts between the two. With the range being where it is filter alignment is pretty much out of the question.

And finally the pesky 20/30 meter receive problem. I do hear some faint signals but only with slug in L9 screwed all the way to the bottom of the can which seems odd. C23 doesn't seem to affect the receive level at all. L8 and C21 offer very distinct differences in receive level when they are adjusted.

A wire from the antenna to C21 and C23 makes a huge difference in receive level. I have literally removed all the toroids from the 20/30 meter LPF area and checked for continuity, number of turns and correct cores. I have desoldered and resoldered all the other associated parts in the LPF. Since this appears to be band specific should I try the signal tracing procedure? I don't have a signal generator so I'm not certain if I can accomplish this with atmospheric noise or not.

I keep thinking I'm missing something simple that's right in front of me. If all else fails I'll send it back to Elecraft but I'm not ready to admit defeat just yet. So any ideas would be appreciated to point me in the right direction for either of these two issues.

73, Ed N0EHQ
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[Don Wilhelm-3]

Ed,

BFO problem - be certain you have the correct capacitors at C173 and C174,
then check the varactors D37 and D38 - they should be the smaller ones -
1SV149 type.  As a check on the voltage swing being applied to the
varactors, monitor the voltage at Control Board U10 pin 14 while in CAL FCTR
mode and tapping BAND+ and BAND-, you should see the voltage change between
0 volts and 8 volts.  If indeed you observe the correct voltage swing, look
for the problem in the VFO area, carefully checking the components and
soldering again - especially RP6.

On your 20/30 meter problem - you should obtain a very nice peak on 30
meters with L9 near the top of the can (L9 does have the long slot slug,
does it not?) - the slug location should be similar to that of L8.  Check
L9, C22, C24, C25, and C29 for proper values, and check carefully for proper
soldering of those components as well as K4B.

73,
Don W3FPR

----- Original Message -----

Now I have been chasing the BFO range. The high end of the BFO range is
4918.2 which is quite a bit high from what the manual gives as an
expectation (4916-4917). The low end of the range is 4914.8 which isn't even
close to the expected range (4909-4912) as indicated in the manual. The
resulting range is 3.4 which is too low. I have tried new crystals with
virtually no change in range. L33 appears to be intact and constructed
correctly in conjunction with R116. I even slipped a small piece of doubled
over electrical tape between L33 and R116 to ensure that there were no
shorts between the two. With the range being where it is filter alignment is
pretty much out of the question.

And finally the pesky 20/30 meter receive problem. I do hear some faint
signals but only with slug in L9 screwed all the way to the bottom of the
can which seems odd. C23 doesn't seem to affect the receive level at all. L8
and C21 offer very distinct differences in receive level when they are
adjusted.

A wire from the antenna to C21 and C23 makes a huge difference in receive
level. I have literally removed all the toroids from the 20/30 meter LPF
area and checked for continuity, number of turns and correct cores. I have
desoldered and resoldered all the other associated parts in the LPF. Since
this appears to be band specific should I try the signal tracing procedure?
I don't have a signal generator so I'm not certain if I can accomplish this
with atmospheric noise or not.

I keep thinking I'm missing something simple that's right in front of me. If
all else fails I'll send it back to Elecraft but I'm not ready to admit
defeat just yet. So any ideas would be appreciated to point me in the right
direction for either of these two issues.



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Elecraft web page: http://www.elecraft.com