Thanks for the input, everyone. When I have the time, I'll throw in some
MPSA's at Q9 and Q10 (which I happen to have on hand), and I'll report
on the results. I'll also check the BFO circuitry again for any problems.
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Excellent catch by both you and Jim, K4ZM, who replied off line. A flaky
input stage to the counter certainly would fit the symptoms.
Please, never be shy about speaking up on the reflector! That's what makes
this forum so valuable.
It's been nearly four years since I built old number 1289 and
Jason,
Visually check the two transistors that form the preamplifier for the
frequency counter (Q9 and Q10, I think). If they have a shiny bluish
face on the flat side, Elecraft will send you two replacements (totally
black). I had this exact problem caused by low or no gain in the
transistors.
A possible cause of misreading the BFO frequency at TP2 may be due to the K2
frequency counter being insensitive.
See Elecraft Builders Alert #21 of October 19, 2004.
Recent kits issued with the blue colored MPS5179 used in the K2 frequency
counter input circuit have been found to have low
It looks like the counter is only registering half the frequency and it's
really at 4912 kHz.
I don't think it's physically possible for the BFO to oscillate down there.
Certainly not under crystal control. C22 won't vary your counter time base
enough to cause anything like that sort of error. Yo
Jason,
Yes, 2456 kHz IS way too low - in fact it is quite out-of -bounds - and is
close to only half the frequency that it should be.
First thing to check is soldering, then re-check the soldering, and when you
are finished, check soldering again. Use the schematic to identify those
compone
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