[Elecraft] K1 issue on 20M (not crystal related)

[Don Herring]

Greetings

I'm a newbie building a K1-4.  Everything was going OK until the 
receiver alignment phase of the build where I ran into a problem where I 
could not hear anything on 20M.

After searching the list and several exchanges with Elecraft support, I 
had not gotten anywhere in resolving the problem.   Based on previous 
issues seen on the list regarding 20M, Elecraft did send me a couple of 
replacement crystals for the band.

In the mean time, I completed the transmitter section and was able to 
get output on 40, 30, and 15 - no output on 20 as per an external 
wattmeter.
 
Replacing the 20M crystal had no effect.  Using my Ten-Tec RX-320D, I 
was able to verify operation of all the crystals, including 20M.

I put together a RF probe this weekend and started signal tracing.  This 
is what I have found, though the finding does not make much sense to my 
inexperienced mind.

At step 8 in the signal tracing procedure in the K1 Manual, I was 
getting 0 voltage on 20M, and anywhere from 0.025 t0 .035 on the other 
bands. 

I started tracing back from P1 pin 6, and took a reading at T2 which is 
the source of my puzzlement.

I can see voltage on all bands going into T2 on lead 3, but no voltage 
at lead 2 for 20M - I'm getting a reading on lead 2 for all other bands.

So it appears T2 may be the source of my problem.  But it doesn't click 
with me that the toroid can be a problem with just one band.

One other oddity is that even though I'm not seeing any signal on the 
external wattmeter I can hear 20M on the RX-320.

Am I on the right track here, or do I need further testing before 
working on T2?

THX, and 73

Don, KJ4MRB