[Elecraft] K2 #2172 is now a 3000+ but...

[Kevin Cozens]

Greetings.

I have applied all the mods needed to bring my K2 #2172 up to the 
equivalent of a 3000+ unit. While doing some realignment of a few of the 
areas where mods were applied turned up something odd.

While working on the bandpass filters I found that C44 on the RF board is 
very sensitive. A very tiny turn of C44 causes power output to swing 
between very low to near the level it should be to very low once more. It 
seems that the tuning of the filter for the 12m band is now very sharp as 
far as C44 is concerned. I didn't have that problem before applying the mod 
kits. I think the problem is the result of the VFO ALC and 10/12m Bandpass 
Filter mod (E850093).

Also, my 8V regulator on the control board is putting out 8.45V which is 
affecting the AGC. The notes on LA3ZA's web site mentions that R1 should be 
adjusted so that pin 5 of U2 measures 3.9V but it doesn't state the 
conditions under which that measurement should be made. Ie. which band, 
pre-amp on or off? antenna connected or not?

The PLL TC mod is great. A tiny board and resistors so I used a meter to 
measure all the resistors to make sure I got the right ones. My eyes aren't 
that bad but most of the color bands were really tiny. The board went in 
and the PLL still worked on the first try. The board won't sit parallel to 
the control board due to it being up right against one of the brown pillow 
type capacitors but that is just cosmetic. Preliminary tests after double 
checking C22 and running CAL PLL indicates that I have also improved my 
frequency accuracy. I am dead on frequency on 40m and only about 50Hz off 
on the upper end of 30m. Now that the weather has started to seem more like 
summer I'm looking forward to testing how well the frequency accuracy and 
stability holds up as the ambient (and internal) temperature changes.

Cheers!

Kevin.  (http://www.interlog.com/~kcozens/)

Owner of Elecraft K2 #2172        |"What are we going to do today, Borg?"
E-mail:kcozens at interlog dot com|"Same thing we always do, Pinkutus:
Packet:ve3syb@ve3yra.#con.on.ca.na|  Try to assimilate the world!"
#include <disclaimer/favourite>   |              -Pinkutus & the Borg