Posted by
g7vjr on
Aug 16, 2007; 2:51pm
URL: http://elecraft.85.s1.nabble.com/K2-PLL-range-test-failure-tp451443.html
Hi -
I'm part way through building a K2 (previously, I have built a KX1,
which was a success). On the K2, I am on the Alignment and Test, Part
II section where the PLL reference oscillator range test is performed
using the probe connected to TP3. This is on page 63 of the guide.
Unfortunately, my numbers don't look good. The Ref. High Freq is
12109.52 and the Ref. Low Freq is 12107.88 (the difference is just
1.64kHz, far below the acceptable range of 9.8 and 15kHz). In
particular, I was expecting the low freq. to be 12080-12090.
Everything else is ok up to this point, eg C22 trim to 4MHz was fine,
and the control board, front panel etc are all working fine, as far
as I am aware.
I am not sure what to try in terms of diagnosis on this. So far I've
retraced all the steps building on the RF board (and actually found a
mis-placed capacitor, so that's fixed). I've also cleaned the board
in case it's that, although I must stress I am not using water based
solder, just a quality lead/tin solder. However, after all this (and
with high hopes!) I powered up again and got the same numbers.
I have been wondering if the thermistor board could be involved. It
is a tight fit and I suppose I might have damaged (ESD or heat)
something. Any suggestions gratefully received, I'm stuck!
73
Michael G7VJR
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