Q7 failure in K2

Posted by N9AUP on Feb 18, 2012; 8:17pm
URL: http://elecraft.85.s1.nabble.com/Q7-failure-in-K2-tp7297576.html

After 2 weeks or so of happy operating of my newly assembled K2, Q7 exploded with a loud snap.  From what I read here, I'm going to have to replace the whole transmit transistor kit.  I did see that this failure has happened to others, so I'd really like to hear if those who had the experience were able to identify the cause of the problem.  Replacing the TX chain will be bad enough--I don't want to have to do it a second time.

What's crazy here is that I wasn't in transmit mode when it happened.  Actually, I had gone over to change taps on my ladder line tuner to change bands.  There was a considerable static build-up on the antenna and I got a small spark when I went to change a tap...and the Q7 let go at the same time.  That could have been a complete coincidence. . .but it still seems strange.  Any thoughts or experience regarding possible causes?

thanks,

George
N9AUP