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Anything else in TX

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n0jrn

Anything else in TX

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 !

72 Jerry N0JRN

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Don Wilhelm-4

Re: Anything else in TX

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 !
>
>
>

______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html

n0jrn

Re: Anything else in TX

In reply to this post by 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 ([hidden email]) 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,
>

Don Wilhelm-4

Re: Anything else in TX

Jerry,

Yes, the PA kit seems to be in order for your K2.
Remove the KAT2 for the initial testing and run the K2 directly into a
good 50 ohm dummy load. No sense in confusing the issue with 'extras'
that could add confusion to the results - take things one at a time and
verify each one before adding an additional element.
After you get the PA kit installed, check the DC voltage at the base of
Q7 and Q8 during a TUNE operation - it should be close to 0.6 volts - if
it is greater than 0.63 volts, you likely have a problem in the Q11/Q13
circuit (damaged thru-plated holes).

Once the K2 PA is under control, you can add either the KAT2 or the
K60XV - do that one at a time and stop if the option added does not
check out properly. I suggest verifying the KAT2 first.

If you are using the KAT2 and the K60XV together, be certain you have
changed KAT2 R6 from 47 ohms to 470 ohms - there was a 470 ohm resistor
provided with the K60XV kit.

73,
Don W3FPR

n0jrn wrote:

> 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
>
>