[Elecraft] Solved: Sick K2 following A to B mod

[bills4570@att.net]

Hi there,

I'm almost embarassed to take up the list's time with this, but I suffered over 
it, and if it saves someone else some time, I think it's worth it:

A couple months ago, I performed the A to B mod on K2 serial number 2715.  When 
I finished, I found that I had intermittant audio performance due to an 
incomplete trace cut.  I stepped back through my steps on the audio pot mod and 
found and corrected the problem.

After that, I was never completely sold on the receive performance, but I had 
changed antennas during the A to B mod, and I attributed the poor receive 
performance to the compromise antenna (aren't they all!), and to a downturn in 
the band conditions.  

One Saturday morning, I was scratching for a PSK-31 QSO, and found that others 
could hear me fine, but that I couldn't copy them!  Now that was a switch for a 
low power addict like myself!  One chap, who I could not hear, was kind enough 
to send me a signal report by e-mail.

I dragged another transceiver out of storage and started doing some receive 
performace comparisons.  I found that the K2 receiver was practically dead.  On 
PSK, the waterfall was filled with signals using the Brand X tranceiver, but 
the K2 showed only the 3 strongest ones.  Hmmmmmmm......

I spent the day tearing the K2 apart and checked each and every step of the A 
to B mod.  I re-flowed each and every solder joint that would have anything to 
do with receive sensitivity.  There was no improvement.  The K2 sat there on my 
bench with a taunting smirk on it's front panel for a few more days, while I 
broke the arms off my Wayne and Eric voodoo dolls.

Yesterday, I took the top off to do some signal tracing.  #2715 is equipped 
with the internal ATU, which is removed with the top.  I began wondering how 
the RF signal could be introduced without the antenna connections in the top 
cover.  I decided to try the original connector, which was capped off....... no 
luck.

On a whim, I connected the antenna to the receive only connector, which came 
with the 160 M kit.  Wow, the receiver spang to life!  You know the rest of the 
story........  Sheeeeesh!  I had never checked the menu selections for the 
receive antenna, and the K2 was set up with the receive antenna "on".  That 
meant that the receive path through the Ant 1 and Ant 2 connections was 
disconnected except on transmit.  A quick re-configuration of this feature 
brought the K2 back to it's hot receiving self. The "Rant OFF" selection must 
be done for each band unless you WANT to use a seperate receive antenna (like 
on 160, for instance).

It had been a major case of "OPERATOR ERROR" the whole time.  I had become used 
to the features I used most often, but forgot about the many other useful 
features which make the K2 such a great rig!  Hope this post helps someone to 
avoid this problem. 

--
Bill Schwantes, 
W7QQ