k2 control board r18, r19

[jon howe-2]

Hi folks:
The quest to transform K2 S/N 3460 into something greater than the sum
of its parts has finally begun in earnest.
I am working on the Control Board right now.
I just want to confirm the assembly instructions:
R18 and R19 are basically resistors with value of 0 (zero) ohms.
So you solder in a piece of wire for each of them.
Then if and when you are ready to install KAF2, you desolder and remove
the two wires at R18 and R19.
With my trusty Hakko 936 at the ready, soldering is a joy.
Desoldering, on the other hand, is something I can't seem to do even if
my life depended on it.
I know what conventional wisdom has to say about silver solder, but
that's what I am using because it just seems so much easier to solder with.
Plus, like writing a math test with a pen, it's a terrific incentive to
get things right the first time.
The downside is, with my skills, or lack of, if any desoldering has to
be done, the patient will surely die.
Any thoughts on a "solderless" solution to R18 and R19?
73,
ve8jj


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Ron D'Eau Claire-2]

Jon, VE8JJ, wrote:

I just want to confirm the assembly instructions:
R18 and R19 are basically resistors with value of 0 (zero) ohms. So you
solder in a piece of wire for each of them. Then if and when you are ready
to install KAF2, you desolder and remove the two wires at R18 and R19.

With my trusty Hakko 936 at the ready, soldering is a joy. Desoldering, on
the other hand, is something I can't seem to do even if my life depended on
it.

I know what conventional wisdom has to say about silver solder, but that's
what I am using because it just seems so much easier to solder with. Plus,
like writing a math test with a pen, it's a terrific incentive to get things
right the first time.

The downside is, with my skills, or lack of, if any desoldering has to be
done, the patient will surely die.
Any thoughts on a "solderless" solution to R18 and R19?

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

Hello Jon:

Because R18 and R19 are jumpers, they are easy to remove: just cut them. If
you want to clear those pads, you can simply heat the pads while holding the
cut jumper and pull *gently*. When the solder melts, it'll slip right out.

There's nothing inherently "better" about using silver solder in the K2. It
is needed in certain very critical RF applications where very high RF
currents are flowing at very high frequencies. For example, in some 900 MHz
repeater equipment that I've serviced the manufacturer required that silver
solder be used in its power amplifier circuits.

Elecraft backed off of suggesting silver solder because it offers no
technical or performance advantage and is slightly harder to remove. Still,
you shouldn't have any trouble if you use a good quality solder-sucker like
Elecraft recommends. Solder wick will work FB too, when done properly. What
most ops miss is that you *must* raise the temperature of your iron when
using wick. That wick soaks up a lot of heat. I crank up my soldering iron
temperature to 800 to 850 degrees F and then use narrow wick and work at the
*end* of the wick (keep cutting away the used segments) to minimize the
amount copper there to absorb heat from the iron. Done that way, sometimes
the wick is faster and easier for me than pulling out the solder-sucker.

Board traces get lifted when too much total heat energy is put onto them,
not by temperature alone. An iron or wick that is just barely hot enough to
work so it must be left in place a l-o-n-g time will do far, far more damage
than a hotter iron or wick left on there a short time.

By the way, I *never* took a math test using a fountain pen! I was the guy
sitting there in a cloud of eraser dust with a pocket full of pencils.

You have courage Jon, and I'm sure that your pride in the work and the
performance of your K2 will reward you in the end!

Ron AC7AC


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[John Lonigro]

Jon:
If you are sure you intend to buy the audio filter, you can buy the kit
now and install the proper connectors right away.  You can then use a
couple of scrap resistor leads as jumpers to make the required
connections - the same as if you had the audio filter installed and
wanted to remove it for some reason.  The filter instructions tell you
how.  Or perhaps you could buy and install just the headers now.  You
can get the part number from the audio filter instructions on line.  
That would allow you to choose between the filter and the DSP unit later
on and you'd only be out the cost of the header.  BTW, I'm not a great
fan of desoldering, but I was able to remove the jumpers on my K2 with
no problem.

73's and good luck,

John AA0VE

jon howe wrote:

>
> Any thoughts on a "solderless" solution to R18 and R19?
> 73,
> ve8jj
>
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Philip L Carter]

If you knew the value of the 'resistors' that were going to live there,
and you had them in your stash, you could install them in the proper place
and put a jumper across them on the other side of the board.  Then when it
came time to install the other board, just clip the jumpers (or unsolder
if you are a neat freak), which would be easier with a regular soldering iron.

This won't work in all cases since sometimes you might be installing a
jumper header instead of a cap or resistor.

If this isn't your cup-o-tea, then don't lay the original jumper that
close to the board and make it easy to clip in half.  Then all you have to
do is heat the connection and LIGHTLY pull on the jumper with a pair of
small forceps or needle nose pliers and then clean the hole with the
Hakko.  It's easier to clean out a hole with nothing in it than to try to
force a lead out of a hole with insufficent heat.


NRE/COLE Test Center OH-3
pcarter<at>gcfn.org or wd8qwr<at>arrl.net
Philip L. Carter, WD8QWR
wd8qwr@w8cqk.#cmh.oh.usa.na


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Lloyd Lachow]

Jon, VE8JJ, wrote:

>I just want to confirm the assembly instructions:
>R18 and R19 are basically resistors with value of 0
>(zero) ohms. So you
>solder in a piece of wire for each of them. Then if
>and when you are ready
>to install KAF2, you desolder and remove the two
wires
>at R18 and .R19.

  Confession: I've built everything I've ever built,
including a K1, two KX1s, two Rock-Mites, an ATS-3 and
various test equipment, and now part of my K2...with
the same Radio Shack 30W pencil. I do, however, swap
out the tip once in a while! For solder, I use the RS
2% silver-bearing, thin solder...because it's so nice
and shiny!

  Using desoldering braid, also from RS, has never
been a problem. Placing the braid flat on a filled,
plated through-hole, I hold the iron vertically and
stick the tip into the spot where the hole is, under
the braid, and I watch for the flow of solder into the
braid. The result is a slick, clean hole. Never a
problem.

   mojo!


  LL/K3ESE


               
__________________________________
Do you Yahoo!?
Yahoo! Small Business - Try our new resources site!
http://smallbusiness.yahoo.com/resources/ 
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Bill Johnson-10]

I too built my K-2 and all accessories with the  RS soldering iron.
However, after reading all the interesting stuff on this reflector,
including the Hakko desoldering iron, I finally bought a soldering station
from Hakko and I can testify that soldering life will never be the same.
Incredible difference to have a professional level iron in one's hand.  Now
it is time to build again and I look forward to using it.

Bill
 
K9YEQ
 
...
  Confession: I've built everything I've ever built,
including a K1, two KX1s, two Rock-Mites, an ATS-3 and
various test equipment, and now part of my K2...with
the same Radio Shack 30W pencil. I do, however, swap
out the tip once in a while! For solder, I use the RS
2% silver-bearing, thin solder...because it's so nice
and shiny!

  Using desoldering braid, also from RS, has never
been a problem. Placing the braid flat on a filled,
plated through-hole, I hold the iron vertically and
stick the tip into the spot where the hole is, under
the braid, and I watch for the flow of solder into the
braid. The result is a slick, clean hole. Never a
problem.

 [WRJ] ...



_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com