[Elecraft] Anything else in TX

[n0jrn]

Don:

A little more explanation is in order.  I have the cover off the K2. 
XV50 is not connected at this time.   K60XV board is still plugged in.

I now have Ant 1 of the KAT2 hooked to my dummy load with watt meter in 
series.  Checking voltages at Q7 and Q8 reveal the collector voltage on both 
are way down during transmit.

Collector voltage on Q13 during transmit is also low.

I've got the manuals for the XV50 & K60XV and I'm going digging for the 
source of my mismatch.

For now,    I have ordered the PA kit for the K2 and I'll get it back up and 
running.

Is there anything I need worry about in the K2 other that Q7, Q8, Q11 & Q13 
????

72       Jerry

On 1/18/2010 8:00:13 PM, Don Wilhelm (w3fpr at embarqmail.com) wrote:
> 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,
>