[Elecraft] [K2] Low TX Output on Higher Bands

[Steve Kavanagh]

As I proceed with checking the new-to-me (S/N 5133, bare-bones, no options) K2 out, I'm finding that the maximum transmit power output drops markedly as the frequency goes up.  If I set the power to maximum, I can get the following approximate powers (on CW):

80m: 15 W 
40m: 15 W 
30m: 15 W 
20m: 7 W 
17m: 4 W 
15m: 4 W 
12m: 1.5 W 
10m: 1.5 W 

I've done a few rudimentary checks which I won't list in detail here for now. All transmit tests were done into a dummy load with a good SWR and power levels shown on the K2 LCD and an external meter agreed as well as might be expected. 

Do these symptoms sound familiar to any of you, or will I have to start a full troubleshooting process? 

It might be the same as observed by W6ICM ( http://elecraft.365791.n2.nabble.com/K2-low-output-tt461601.html).  Are there any other theories?

73,
Steve VE3SMA