[Elecraft] K2: Erratic action of the Hand Key "Autodetect" function

[W3FPR - Don Wilhelm]

Jim,

I have also had that occasional problem, and it seems to happen more
frequently if the key contacts are dirty.  Slip a piece of clean paper
between the contacts and close the key just enough to grip the paper gently
as you pull it through - the paper will burnish the contacts and the problem
will likely go away.  I found this out early on (just after the K2 Field
Test).  It does not seem to happen when the K2 is driven from a computer,
but will hppen occasionally when hard key contacts are used, so it must be
due to contact bounce coupled with slight propagation delay differences
through the diodes.

The other thing you can do is to match the diodes for timing (requires a
dual trace 'scope and a square wave generator)  - sometimes one diode is
slower than the other which will create a timing condition, 1N4148 diodes
are usually more consistent than 1N914s in my experience.

I am solving the problem altogether here with a K1EL K12 keyer packaged
externally.

73,
Don W3FPR

> -----Original Message-----
>
> I posted this problem several months ago and never received an answer from
> anyone on it.
>
> My K2 (and I've talked with several other K2 owners with the same
> problem),
> Serial #4338, will not always detect a hand key properly -- Autodetect is
> turned on in the menu - and I am using 2 1N914 diodes between the hand key
> contacts and the dot and dash inputs to the K2.  The keypaddles function
> properly at all times, but when using the hand key, at random times, a key
> down on the hand key produces the same results as a paddle press - namely
> automatic dots or dashes.  This has proved to be a nasty problem,
> especially
> in a contest when needing to rapidly slow down to re-send
> information.  You
> get part way through the exchange and the characters get all messed up due
> to the aforementioned erratic action.
>
>
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