KPA100 option almost done...

[Steve Kallal]

Well after about a month, I almost have my KPA100 option finished for the
K2. I didn't accurately time the hours, but I think it is in the 25 hour
region. This is the first serious kit I've built in years and the most
serious ever. I had only one mistake to correct. U7, the dual op amp, was
reversed. Once that got replaced, the amp came to life.
 
I have a couple of issues left, minor ones.
 
1. The power does seem to vary a little bit on key down, nothing major, but
a few percent before the power level settles. The TUNE function indicates
1.5:1 SWR into a dummy load. Perhaps I need to go back and retweak the SWR
setting.
 
2. The speaker sounds like the cone is bad. I ordered a bunch of parts from
Elecraft, but the speaker slipped my mind. I will need to remove the shield
if the speaker gets replaced. Does the adhesive comes loose easily?
 
Thanks for all help from this reflector!
 
73,
 
Steve N6VL
 
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[Don Wilhelm-4]

Steve,

If your dummy load is indeed a 50 ohm non-reactive load at the frequency
of operation, it should indicate a 1:1 SWR if you used it when you
balanced the wattmeter (C1 adjustment).  Adjust C1 with an insulated
screwdriver because both ends of the trimmer cap are above ground and a
mettalic adjustment tool in the slot will change the capacitance.  If
you have any doubt about your dummy load, borrow an antenna analyzer and
measure it at the frequency of interest.

As for the speaker, the shield will not release easily - you may want to
consider ordering another shield too if replacement is in order.

Sometimes the speaker frame becomes distorted during shipping - often
that can be detected by gently prying upward on the 4 frame webs while
listening to the speaker - if the fuzziness goes away when gently prying
one web, apply a bit more pressure in an attempt to form the frame a bit
and get it to work satisfactorily.  When evaluating the sound of the
speaker, do not lay the KPA100 upside down on a flat surface - the
surface reflects some of the sound and can actually make it sound
terrible even though all is well.

73,
Don W3FPR

Steve Kallal wrote:

> Well after about a month, I almost have my KPA100 option finished for the
> K2. I didn't accurately time the hours, but I think it is in the 25 hour
> region. This is the first serious kit I've built in years and the most
> serious ever. I had only one mistake to correct. U7, the dual op amp, was
> reversed. Once that got replaced, the amp came to life.
>  
> I have a couple of issues left, minor ones.
>  
> 1. The power does seem to vary a little bit on key down, nothing major, but
> a few percent before the power level settles. The TUNE function indicates
> 1.5:1 SWR into a dummy load. Perhaps I need to go back and retweak the SWR
> setting.
>  
> 2. The speaker sounds like the cone is bad. I ordered a bunch of parts from
> Elecraft, but the speaker slipped my mind. I will need to remove the shield
> if the speaker gets replaced. Does the adhesive comes loose easily?
>  
> Thanks for all help from this reflector!
>  
> 73,
>  
> Steve N6VL
>  
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
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>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
>
>  

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[Curt Milton]

FB on your progress.  I built mine a few months ago
and really enjoy operating the rig.  

I suspect the power variation you cite is merely
thermodynamics.  Did you happen to touch the finals
key down?  

The VSWR sensor likely needs tweaking per the manual
instructions - mine recognizes a match pretty
accurately.  

My built-in speaker sounds dreadful as well !  I
wonder if its the impact of the metal shield ?  It is
especially sour sounding on CW, SSB is not quite as
bad.  If you do remove the shield, see how the speaker
sounds.  I figure the shield is to keep it from
becoming a receiver at 100 watts, and thumping on CW?

Proceed with care and enjoy the extra 8 dB gain in
output power.  

73, curt

--- Steve Kallal <[hidden email]> wrote:

> Well after about a month, I almost have my KPA100
> option finished for the
> K2. I didn't accurately time the hours, but I think
> it is in the 25 hour
> region. This is the first serious kit I've built in
> years and the most
> serious ever. I had only one mistake to correct. U7,
> the dual op amp, was
> reversed. Once that got replaced, the amp came to
> life.
>  
> I have a couple of issues left, minor ones.
>  
> 1. The power does seem to vary a little bit on key
> down, nothing major, but
> a few percent before the power level settles. The
> TUNE function indicates
> 1.5:1 SWR into a dummy load. Perhaps I need to go
> back and retweak the SWR
> setting.
>  
> 2. The speaker sounds like the cone is bad. I
> ordered a bunch of parts from
> Elecraft, but the speaker slipped my mind. I will
> need to remove the shield
> if the speaker gets replaced. Does the adhesive
> comes loose easily?
>  
> Thanks for all help from this reflector!
>  
> 73,
>  
> Steve N6VL
>  
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft   
>
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

       
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