[Elecraft] KRX3 Removal/Installation

[Ron D'Eau Claire]

Great, Ed! I bet most of that time was spent removing/replacing screws! 

I mention that because I often work servicing radio, radar and other
electronics in the field. It's not uncommon to find a panel fitted for 10
screws held in place with only four or five. 

Sure, that panel isn't likely to fall off with four or five screws holding
it, but the shielding and mechanical integrity are badly compromised. One
time I visited a large bulk-cargo ship that had to be manually steered every
moment - a huge problem with the small crews large ships carry today. They
had been doing that for almost a week crossing the Pacific before they had
me jump on a fast launch and catch up with them as they were traveling up
the Sacramento River - a very narrow channel where steering glitches are
most unwelcome. I found that, in some far away port, a tech had failed to
tighten the screws on a gyrocompass amplifier module. That caused the
auto-pilot to go crazy at random intervals. 

With the K3, loose or missing screws can lead to strange noises and birdies
in the receiver or one might experience troublesome effects like "RF in the
shack" that are really just "RF leaking into the wrong place", jumping
frequency, changing SWR while transmitting, distortion in transmit audio or
mysterious "shut downs" during a QSO, just to name a few possibilities the
result of bad shielding or loose connectors. You're not likely to run the
shack "aground" on a river bank, but why suffer a poorly working rig just to
save a few minutes? 

And, in the K3's advanced mechanical design, the relatively lightweight
case's exceptional strength is due in no small part to the combined strength
of all of those screws. Without all of them, the mechanical strength of the
K3 is reduced.  

Bottom line, to have the K3 work properly, do *not* randomly leave parts out
or installed loosely after working on it - even screws ;-)

Ron AC7AC


-----Original Message-----
K3 Field Test has been trying out some draft instructions for removing the
KRX3 and re-installing it.  This is necessary for changing crystal filters
in either the main receiver or the KRX3, or adding/removing other K3
options.  It took me four minutes to remove the KRX3 module and nine minutes
to re-install it.  Another minute would be required to remove the front
bottom cover to get at the main receiver crystal filter screws and several
minutes to remove the shields from the KRX3 to get at its crystal filters.
All in all, not a big deal, and once again a great tribute to the K3 design.

73,
Ed - W0YK