[Elecraft] Anything else in TX

[Don Wilhelm]

Jerry,

One thing at a time is certain.  I figure you are using the normal K2 
output to drive the XV50 - if you are using the K60XV outputs, the PA 
should be disabled (no drive).

See if the K2 does the same thing on 28 MHz with a dummy load attached - 
if it does, then you are correct to blame the PA transistors (and 
Q11/Q13) rather than the XV50.  Test one element at a time - trying to 
do the K2 and the XV50 together is an exercise to create frustration.  
Be certain the K2 is behaving properly into a dummy load before adding 
the XV50 to the mixture of 'things that could be wrong'.

If your XV50 does represent a high SWR, then you have made an error in 
the input attenuator section.  The attenuator alone should assure a good 
50 ohm load to the K2.

Yes, I do suspect that you have a K2 PA problem - if you have changed 
Q11 and Q13 before, make certain that the hru-plated holes have not been 
damaged in the removal process.  If that is a possibility, solder the 
Q11 and Q13 leads both on the top and bottom of the board (there is no 
need to mount the transistors flat to the board - leave about 1/8 inch 
of lead above the board.

73,
Don W3FPR

n0jrn wrote:
> Evening gang:
>
> Having some fun with my K2 these days.   I've been attempting to set up my 
> new K60XV and XV50.
>
> While trying to set the inductors inside the XV50 I noted I wasn't getting 
> enough drive from the K2 to bring the voltage up where it should be.
>
> Back to that later !
>
> Now I'm seeing high current in the K2.   5 watts output show nearly 4 amps 
> draw.     OUCH
>
> Checked Q7 and Q8 and dang if my collector voltage isn't dropping way down 
> on both.  Q7 drops to approx 6.5 volts and Q8 all the way down to 3.5 volts.
>
> Dang it !                Checked Q11 and Q13 and the collector on Q13 is 
> also low.  I'm headed to Elecraft to order the PA kit for repairs. 
> Anything else I need to be checking ?????
>
> FWIW        K2 still putting out approx 8 watts but current is way up.  I'll 
> assume the PA will fix my problems and I can go about figuring out why the 
> K60XV represents such a high SWR.
>
> I did recheck the I/O for the board and that was good.
>
> OH Well !     One thing at a time !
>
>   
>