[Elecraft] K2 100 Watt Pa Problem

[DW Holtman]

Hello,

I was wondering if anyone else has had a problem like ythis one?

I'm was in the process of finishing up my KPA 100. All of the power supply, 
bias adjustments etc went as per the book. When I got to page 50 in the 
manual to test the transmitter at high power the problem shows up.

With the Power out turned to around 11 watts, the relay clicks and the power 
out is taken over by the KPA 100. Every thing works great until I get to 
right at 20 watts. Any power level 20 watts or over, when it is keyed, a 
relay klicks, power out shuts off and nothing out. At 18 watts the power out 
from the KPA 100 is fine. There are no error messages that I can find, even 
on the secondary message menus.

Any suggestions why the PA works up to 20 watts then shuts down with no 
error message?

Best,
DW Holtman
WB7SSN

----- Original Message ----- 
From: "Ron D'Eau Claire" <ron at cobi.biz>
To: "'Nelson Wittstock'" <k8djc at zoominternet.net>; 
<Elecraft at mailman.qth.net>
Sent: Sunday, March 30, 2008 2:00 PM
Subject: RE: [Elecraft] Soldering station


I just ordered the new KXV3 RXA board for my K3.  The instructions state
requirements for the soldering station to be used in the installation of the

new board.  My workshop has never had need for "high tech" soldering and
consequently I do not own a soldering station.   I have several assorted
soldering irons and guns that have served me well in the past but I guess I
will have to join the modern world.  Since I would like to keep updating my
K3 it looks like I will need to buy a soldering station.  In looking through

Googled references I see many stations in the $100 and up range.  Is it
absolutely necessary to spend that much to ensure the safety of my radio or
are there some less expensive suitable alternatives?

Nelson - K8DJC

------------------------------------------

That mod is one of the easiest in terms of soldering. You are soldering two
fine wires to closely-spaced connector terminals that, if overheated, will
melt the connector header or lift traces. But it's not nearly as critical as
many component installations in other locations. Two more leads are
connected to BNC connector terminals that require significant heat in any
case. The RXA board comes with the leads pre-attached, so there's no
soldering to do to the RXA board itself.

It's a judgment call. Elecraft wants you to be successful and your chance of
having trouble is greatly reduced by using the right tools, and a good
soldering station is a tool you'll use again and again if you do any work on
your rigs.

You can get away with less. I've repaired a lot of SMD circuit boards
sitting cross-legged on the deck in the navigating bridge of a ship using a
portable butane-powered soldering iron while holding a flashlight in my
teeth.

I've also had lots and lots of practice over decades of soldering that lets
me judge the temperature of the tip by the smell and, by being very, very
careful, I've yet to destroy a board or parts. I did have the advantage of
"growing up" with the pc board industry, first working on boards back in the
1960s that had large push-in pins to which leads were soldered, then boards
with big thick, wide traces that have slowly evolved into the tissue-thin,
tiny traces we find on many boards today.

Even so, whenever possible I'll use a temperature-controlled soldering
station in a comfortable, well-lit shop.

Over time, I've found that a good soldering station costs me pennies a month
to own and use. I don't consider that too much to spend to protect circuit
boards, almost any one of which is worth more than the iron.

I currently have a Hakko 936 that cost me less than $100 several years ago
from www.tequipment.net.

Bottom line, it's a matter of how skilled you are at soldering and how much
risk you are comfortable taking with the pc board and components.

Ron AC7AC


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