Keying Mod; Construction technique

[Paul Clay]

I just purchased the KPA100 for my K2 (serial
3640), and in going over the instructions I see
that the installation of the keying modification
is highly recommended.  I'm a little nervous
about the part of the mod that requires the
cutting of a circuit trace.  What's the best way
to perform this operation?  (Kind of a shame to
have to hack at my K2 this way, but you gotta do
what you gotta do.)

- Paul, N6LQ
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[Hisashi T Fujinaka]

The way I like to do it is to get an X-acto knife or another sharp knife
and carefully score the trace in two spots. Use repeated shallow cuts.
Heat up the little bit between the score marks with a soldering iron and
it should lift off (and stick somewhere you don't want it to stick, but
that's just my luck.)

On Mon, 14 Nov 2005, Paul Clay wrote:

> I just purchased the KPA100 for my K2 (serial
> 3640), and in going over the instructions I see
> that the installation of the keying modification
> is highly recommended.  I'm a little nervous
> about the part of the mod that requires the
> cutting of a circuit trace.  What's the best way
> to perform this operation?  (Kind of a shame to
> have to hack at my K2 this way, but you gotta do
> what you gotta do.)
>
> - Paul, N6LQ
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
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--
Hisashi T Fujinaka - [hidden email]
BSEE(6/86) + BSChem(3/95) + BAEnglish(8/95) + MSCS(8/03) + $2.50 = latte
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[Tom Hammond-3]

Hi Paul:

At 11:31 PM 11/14/2005, you wrote:
>I just purchased the KPA100 for my K2 (serial
>3640), and in going over the instructions I see
>that the installation of the keying modification
>is highly recommended.  I'm a little nervous
>about the part of the mod that requires the
>cutting of a circuit trace.  What's the best way
>to perform this operation?  (Kind of a shame to
>have to hack at my K2 this way, but you gotta do
>what you gotta do.)

It's not THAT difficult to do, though it does take some 'intestinal
fortitude' to do it if you've never done something like that before. <G>

The way I do it is to use an Xacto knife with a new (e.g. sharp) blade.

Note - If you use the 'standard' Xacto knife & blade, the tip of the blade
will probably break as soon as you press down hard on it!!!  But that's
actually OK< since you really want to be able to use the next-in section of
the blade anyway, 'cause it's stronger... heheh!

First, DO NOT (ever) DRAW the blade across the land being cut!!! This
almost always guarantees you'll slip somewhere along in the process and
drag the cutting surface across several other lands (not intended to be cut
or TOUCHED by the blade).

Place the blade, about as flat on the land as you can, and press it
directly DOWN onto the PC board. This will take some effort, and as I noted
above, will often cause the thin tip of the blade to break off. Just
re-group and re-start with the thicker end of the tip now available.

Once you have made your initial downward cut, move the blade about 0.05"
(less than 1/16") to one side of the first cut and repeat the effort.

Once you have made two cuts in the land, use the sharp edge of the blade to
get under and lift the cut section of land free of the PC board. A little
added (angular) pressure to get under the cut section of the land will help
here.

Some folks have also had success using their soldering iron tip to heat
just the severed section of land, cause it's adhesive to loosen, and then
lift the copper free. I've used this method as well, but find the above
method to be a bit safer in some respects since it doesn't run the chance
of accidently overheating and lifting the ends of the cut trace as well.

If you're going to attach a component across the severed land, once you
have the land severed and the cut-out section removed, use your Xacto knife
(or whatever knife you're using) with the blade FLAT against the ends of
the severed land, to scrape off a bit of the green solder mask. Repeat
until the copper is bright and shiny. Then quickly (and lightly) tin the
bright copper, using moderate heat and minimal solder.

This is only the way _I_ do it. Before you jump in, be sure to read other's
responses as well and then use the one you feel most comfortable with.

73,

Tom Hammond   N0SS

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[Don Wilhelm-3]

Paul,

Cutting PC lands for changes/upgrades is an industry accepted practice, so
it should not be regarded as 'hacking' at all - the result will still look
neat and clean.

There are many ways to make a cut - if there are a lot of cuts the easiest
is to use a small dental burr (it could be a Dremel wit a very tiny burr
bit), or for one or two cuts, a sharp knife will suffice.  I usually use the
tip of my pocket knife just because it is handy (and yes, it will need
sharpened afterward).  I cut a 'V' groove through the circuit trace with the
tip of the knife - I exert some downward pressure with one hand and control
the knife blade with the fingers of the other hand placed on the back of the
blade near the tip - it does take some pressure there as well.  I make 2
angled slicing cuts about 1/16 inch apart and flick out the cut piece.
Check continuity before and after the cut to be certain that the copper has
been completely severed.  It is harder to explain than to do.

73,
Don W3FPR

> -----Original Message-----
>
> I just purchased the KPA100 for my K2 (serial
> 3640), and in going over the instructions I see
> that the installation of the keying modification
> is highly recommended.  I'm a little nervous
> about the part of the mod that requires the
> cutting of a circuit trace.  What's the best way
> to perform this operation?  (Kind of a shame to
> have to hack at my K2 this way, but you gotta do
> what you gotta do.)
>
>

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