[Elecraft] K1-4 receive sensitvity problem - found!

[Thomas]

Eureka!

For the benefit of future K1-4 builders, I will publicly humiliate myself
and tell you what was causing the very poor receive sensitivity. The hint I
had about CB, CD, CF, and CH, not showing any peak was valid. Using N0SS'
"Cheap and dirty signal tracing in the K1," and later an HP3325B function
generator, the signal was found to be dying at T4. When I originally
installed T4, I recalled having problems getting the leads to line up with
the PCB holes. I managed to get it installed, but that difficulty stuck in
the back of mind.

Yesterday, I decided to pull T4 after finding nothing wrong with K5, or the
associated filter capacitors. Once T4 was out of the circuit the problem was
obvious; it wasn't T4, but instead T2! I had somehow switched T4 and T2.
Getting them out cleanly was a task; and I even ended up rewinding T4. But
when they were correctly installed the alignment behaved as it should. CB,
CD, CF, and CH all produced a distinct peaking of the signal. Their
associated peak may not be as sharp as that had by the other trimmers, but
indeed they do have peaks. The receiver aligned perfectly and signals are
now loud and clear on all 4 bands.

Hopefully, others will learn from my error. Onward to the transmitter
section!

Regards, Thomas - AC7A  (Tucson)