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

[Don Wilhelm]

Steve,

I have found that behavior in K2s that have some problem with RFC3. Make 
certain the leads are well stripped and tinned (you should see some 
tinned wire above the board) and RFC3 is wound on the right core - I 
have found a few where the builder used the black powdered iron core 
instead of the ferrite core.

The winding of T2 can reduce the power on higher bands, but not as 
severe as you have, but check anyway to be sure T2 is wound as indicated 
in the manual and spaced 1/16 to 1/8 inch above the board.

You will likely have to do some modified transmit troubleshooting using 
the test points indicated in the manual, but at a higher power setting 
than 5 watts (I would recommend 10 watts setting).  At each test point, 
compare the RF voltage for 20 meters with that for 15 meters.  When you 
find the place where the RF voltage for 15 meters is substantially less 
than that for 20 meters, you have identified the output of the failing 
stage.

73,
Don W3FPR

On 11/8/2014 10:42 AM, Steve Kavanagh wrote:
> 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
>
>