[Elecraft] Bug in Keyer?

[Tom Hammond NØSS]

Hi Steve:

>Anyone else had a problem with the K2 internal CW keyer?
>
>I have a fairly recent model of K2/100 #2751 (v2.02f).
>
>I started using the internal keyer today and found that every now and then
>the keyer locks up and emits a long D-A-H (@30wpm).
>
>The keyer then seems to recover ok.
>
>It's not easy to reproduce - it might happen twice in a 10 minute QSO.
>
>It's nothing to do with "LO BATT" or RF getting into the radio 'cos the
>problem occurs when not transmitting also ("TEST" mode).
>
>I guess I'll go back to using my external keyer until someone can suggest a
>fix for this...

The K2 offers two (2) options for connecting EXTERNAL keying devices 
plugged into the KEY jack with a 1/8" stereo phone plug:

1) You can manually set the MENU item INP to "HAND" which
    tells the K2 to accept ANY input on either the ring or
    tip of the phone plug as a manual key closure. So when
    the external keyer sends CW, it's interpreted by the K2
    as keying.

2) You can also set the K2's firmware to automatically
    LOOK for the closure of BOTH paddles at exactly the
    instant as an attempt from an external keyer to send CW
    directly to the K2.

    This option is discussed on page 92 of the Rev C K2 Manual.
    However, depending upon the vintage of the manual itself,
    this discussion will probably only mention that "Auto-
    Detect" is enabled and won't mention that it's selectable
    with newer versions of the K2 firmware.

    This option ALSO requires that you use a couple diodes
    (1N914's are fine) to AND-together the output from the
    external keyer together so that when the keyer 'closes'
    its output, both the DIT and DAH lines of the K2 are
    pulled to ground at the same instant.

Yeah... I know, by now you're probably getting ready to stop reading, 
saying, "This guy's nuts... I'm NOT using an external keyer." Well, please 
stay with me just a bit longer.

The problem (if you see it as a problem) occurs when AUTO-DETECT is turned 
on (as I believe may be the default action) and then you accidently close 
both the DIT and DAH contacts on your PADDLE (plugged directly into the KEY 
jack, NO external keyer). The AUTO-DETECT firmware can't tell that your 
inadvertent closure of the paddles at the same instant was unintentional... 
it thinks you've plugged in an external keyer (or handkey) and acts 
according to what it thinks it should do.. that being to send a DAH for as 
long as you might have both paddles closed.

So, here you are, happily sending CW from the K2 when, all of a sudden it 
appears to hiccup and send a long DAH... can't force it to repeat the 
action? That's because you're not closing the paddles at the same 
instant... who'd want to, right? So you continue sending CW, but always 
have it in the back of your head, waiting for it to hiccup again.

I believe this problem seems to occur more frequently with those ops who 
actually send CW using true IAMBIC ("squeeze") keying, rather than those of 
us who don't use squeeze keying. But it CAN happen to any of us.

To check to see if AUTO DETECT is enabled in your K2:

   MENU and scroll to INP
     HOLD MENU to move the cursor to the right hand setting
       BRIEFLY press DISPLAY and note whether you see
         "AdEt On" or "AdEt OFF" on the display

         Repeatedly pressing DISPLAY merely toggles this option
         on/off. You want to ensure that "AdET OFF" is shown in
         the display.

   Once reset, HOLD MENU to return to normal operating mode.

Now, should you later decide to key the K2 from an EXTERNAL keying source 
(keyer, bug, straight key, logging software/PC), you will want to either 
turn AUTO DET back on , or set INP to HAND.

Hope this works for you.. if not, I've wasted a LOT of your time.

73,

Tom Hammond   N0SS