[Elecraft] Mods to the K2 - Opinion

[Don Brown]

Hi

Most of the mods to the K2 are simple component value changes and do not =
require any cut runs or wires added to the circuit board. The new VFO =
and BFO mods are just remove and/or replace one of the crystals and =
replace L33 with a new toroid. The band pass filters are component value =
changes, mostly capacitors. If you are careful no one would ever know =
these mods were installed by looking at the insides of the K2.

The 2nd xtal filter flattening mod does not require any cut runs. It is =
installed on the bottom of the RF board and consists of adding a =
transistor, resistor and 2 capacitors. It is not visible unless you =
remove the bottom cover. As there is not much to see on the bottom (and =
there are a few other components mounted on the bottom). If I were to =
show my K2 to someone I usually remove the top cover and not the bottom. =
But if it bothers you, don't install the mod and adjust L34 for the =
flattest filter shape. It will not perform as good as a radio with the =
mod but it may be good enough.

Ok now we are down to the mods that require cut runs and wires added. =
The most visible is the sidetone source mod on the back of the control =
board. You only need this mod if you are going to use the KIO2 or KPA100 =
computer interface. If you never have a need for this don't do the mod. =
The most difficult mod is the AF pot noise mod and it requires several =
runs to be cut and several wires added. This mod has always been =
optional. If your AF gain pot is not noisy or you can live with it, you =
don't need the mod. BTY this mod is difficult to see if done properly as =
most of the changes are on the bottom of the RF board and front of the =
front panel board covered by the front panel.

The only other cut run required is to install a DC blocking capacitor in =
series with the AUX RF output on the bottom of the board. This will =
protect the relays in the LP filters from damage if you plug the AUX 12 =
volt cable into the RF connector by mistake. If you don't have the =
battery option or KPA100 then you don't even have the RF connector so =
the mod is not required. If you are careful and think you will never mix =
up the cables don't do the mod.

Perhaps Elecraft will make the control board available as a separate kit =
so you could upgrade to the Rev B version then the most obvious mods =
would not be visible from the top of the K2.=20

Personally I like to tinker with my K2's and enjoy getting a little more =
out of them. Maybe its years of working in a metrology lab calibrating =
test equipment that makes this mindset. I think the K2 can always be =
tweaked up just a little better. So I am always open to any new mod =
someone comes up with that will make it better.

I like the insides of my K2's to look good and when I add a mod it will =
be done as cleanly as possible, but performance is king in my opinion.=20

Don Brown
KD5NDB


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