[Elecraft] K2 Keyer Problem

[Eberhart, Russell]

I have K2 #4650, which has worked flawlessly for about three months.  I have had several hundred QSOs, mainly CW, and have used all bands.  I almost always run 5 watts.  Today, a weird phenomenon raised its head.  On 17M, I finished a QSO with an Italian station, and everything was working great.  I started to call another station, and the keyer started sending a pattern of dot-dash-dot-dash-dot-dash... when I held down the dash paddle.  The dot paddle works OK.  The phenomenon stops when I reduce power below 2 watts or so.  SWR is about 1.2 - 1.3.  I experimented for awhile, and found that I only had the problem on 17M, nothing on 80, 40, 20, 15, or 10.  Then I had a QSO with everything normal on 20M, then returned to exploring the problem.  I now find the dot-dash problem has creeped in on 15M.  Still no problem except on 17M and 15M. I scrolled thru FAQs, but haven't found anything.  I strongly suspect a software problem, but am not sure how to proceed, and will appreciate the wisdom of the gurus on this reflector.
 
Thanks in advance,
Russ Eberhart, N9IV
K2 #4650  KX1 #742