[Elecraft] K3 output power failure.

[Eric Rosenberg]

In the middle of the ARRL 160 contest, my K3 stopped putting out any RF. 
No  explanation that I can think of... all of a sudden, ZERO watts out 
when the radio was keyed, either by software (N1MM+ or WSJT-X) or 
pressing the TUNE button. The TX LED was lit, the meter showed audio, 
which I could hear via the radio MON.

I could not get it to come back. I shut it off for a couple of minutes 
and then it came back.

Everything seemed fine until this weekend's ARRL RTTY Roundup. After 
being on the air for about 4 hours, once again there no was RF output 
(the meter said "0 watts with two dashed lines above it), The radio 
keyed (the TX LED went on and the meter showed audio which could be 
heard via the radio MON), and the meter said "0 watts with two dashed 
lines above it.  I disconnected everything but the antenna, and still... 
no change. I did a system reset. Again, no change.

I quit for he evening and came back in the morning, On a lark, I hooked 
it all back up, and lo and behold, everything worked as if nothing had 
gone wrong.

I'm stumped. I've never opened up the radio -- the only time it was 
opened was at Elecraft last year.

Any advice is appreciated!

73,
Eric W3DQ