[Elecraft] My K2 is now Transmitting 15W on 80M CW but power drops off as I go up bands

[Don Wilhelm]

Cliff,

There are two areas of the K2 transmit chain that have frequency 
dependent components.  The Transmit Buffer and the feedback loops from 
collector to base of Q5 and Q6.

Check the soldering for the components connected to RF Board U9, 
especially R94 and C150 on the bottom of the board.  Also reflow the 
soldering of the components around Q5 and Q6.

One other thing to check is the value and soldering of R98 on the bottom 
of the board - it should be 270 ohms.

73,
Don W3FPR

On 1/9/2013 1:39 AM, Clifford Hynds wrote:
> This is strange,,
>
> My K2 is now Transmitting Max 15W on 80M CW but power drops off as I go up
> bands 6W on 40M about 3W on 30 and not much at all on the other bands.
>
> What would cause a pregressive drop off like this , PA must be ok otherwise
> I wouldn't be getting 15W out on 80M .
>
> I have adjusted to peak the output as per manual but something is obviously
> not right.
>
> Receive side seems to be working correctly, noise when antenna connected on
> all bands , very quiet with no antenna.
>
> thanks for any ideas , seems I am close to a working K2 been spoilt in the
> past most everything I have built worked first time not so the K2 TX side.
>
> thanks for any ideas,
> Cliff VK2CCJ
>