[K2] KPA100 build comments (Sorta long)

[aj4ay]

Group,

I have just completed the build of a KPA100 for my K2 and
wanted to post a few comments about it.

First, let me say that I had forgotten just how much fun it
is to work on an Elecraft product, and how much personal
pleasure I get in doing something myself.  The KPA100 is no
exception to the normal Elecraft standards.  It is an
excellent kit with great documentation and a lot of fun to
build.

Other than a few operator malfunctions (i.e. loose nut
behind the soldering iron), the KPA100 went together with no
problems and worked perfectly the first time (after fixing
the operator errors).  Total actual build time, including
the inventory, was about 23 hours, give or take, over 11
sessions.  In no special order, these are my comments:

1.  DO THE INVENTORY.  While the parts count is much lower
than the K2 kit, caps of the same value have different lead
separations.  Several caps have different shapes than are
usually seen so it is a good idea to get familiar with what
they look like.  Doing the inventory also allows you the
opportunity to group like parts.

2.  Read and follow the directions carefully.  Operator
malfunction #1 was mounting a .001 uF cap (102) in a
position where a .01 uF should have gone.  Having done the
inventory and knowing the cap count was correct, I knew that
I had messed up when I needed a .001uF and all I had left
was a .01uF.

3.  Install the optional inline fuse in the power cord.
This, IMHO, was the most difficult part of the construction.
To be blunt, it was a PITA.  I finally gave up trying to do
it the "book" way and did it my way.  An 11/64" drill bit
opened the ends of the plastic fuse holder for the #12 wire
with insulation.  A 7/64" drill bit opened up the metal
terminal enough to insert the #12 wire sans insulation.
There are two reasons to install the inline fuse.  First, of
course, is for safety/protection.  The second reason is that
by removing the fuse, it makes the insertion of a DC ammeter
in the power line easy so that the bias adjustment can be
performed.

4.  Keep the "Parts Placement Drawing" on page 73 handy.
Positioning of the two trimmer capacitors (C1 and C27) was
made easier using the picture because the silk screening on
the main board was not clear.

5.  Sanding the black oxide finish off of the heat sink made
me really cringe.  This is a beautifully machined part and
having to put sandpaper on it hurt.  Be careful performing
this operation.  It is not a big deal on the bottom of the
heat sink as it is unseen, except by you.  But on page 42 of
the manual, the sanding will be visible if not done
carefully.  The manual provides this warning.  If nothing
else, keep the black sharpie handy.

I want to thank Gary, the Elecraft tech support go-to guy,
for his help in finding a major operator error.  I would
have bet next month's retirement check that I was seeing a
firmware problem during one of the tests.  An LCD message
was completely different from what the manual was indicating
should be seen.  After a few e-mails, the light bulb finally
came on and I found where I had wired the RF plug backwards.
This is the plug that feeds the K2 RF output to the KPA100.
No wonder I was getting a HI CUR message.  Thanks Gary, and
the invitation is always there.

Eric and Wayne have done a great job on the K2 and all of
its various options.  The KPA100 will be an excellent
addition to my station.

Thanks and 73!

Jay
AJ4AY
Mobile, AL


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