Mostly just an FYI, for the benefit of anyone searching the archives
with a similar problem....
Did the rework required to fit KSB2.
"Initial test", The bands were fairly dead, so it was difficult to tell
for sure, I can't really describe quite why, but "stuff just didn't
sound right". I pressed on, and CAL FIL wasn't working. The BFO wouldn't
go low enough.
I removed KSB2, jumpered pins 1+3 of J9+J10, poked C167 into the right
holes of J11 (WAY easier than resoldering), went back to K2 "Alignment
and Test, Part II"...
4MHz difficult to test precisely without another calibrated receiver or
frequency counter, but it was within about 170Hz last time I tried
tuning to RWM frequency reference on 9996 (EU version of WWV, or Russian
in fact). I'll get it even better later, but basically 4MHz was most
likely "good enough" as far as I could tell.
PLL fine, VCO fine, everything between about 1.8 and 6v.
BFO high 4918.07 - OK
BFO low 4914.49 - bad
BFO range 3.58 - bad
Previously I'd got 4917.36 - 4912.54 = 4.82, all good.
L33 looked intact, measured about 1.4ohms. Couldn't spot any damage,
shorts, dry joints... Touched all solder joints on (almost) all
BFO-related components anyway, and now it's back at 4917.36 - 4912.54.
All sorted. Presumably MUST have been a dodgy joint somewhere.
The whole receiver now feels a lot clearer actually. I probably had a
slight problem even before the KSB2 rework, just made more obvious by it.
Pressing on with KSB2 again...
--
"Nosey" Nick Waterman, G7RZQ, K2 #5209.
use Std::Disclaimer;
[hidden email]
Brain cells come and brain cells go, but fat cells live forever.
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