Newly Built KPA500 Acting Strange

[Carl Jón Denbow]

OK, after Tim, M0AFJ, informed me that the amp needed to have fuses, and
I dutifully installed same, everything seemed fine for a little while.  
Thanks, Tim, for the heads up.  At that point I tried it on several
different bands into a dummy load and into the ether and was getting 500
watts out.  Then, I decided to put a watt meter inline to get a more
accurate assessment of wattage and instead I got really low output
readings on several transmissions and then zero.  I then took the watt
meter out of line and now I have the following phenomenon:  1. In bypass
mode I get out full wattage -- 45 watts from rig, but the KPA500 says
it's 35.  The rig's SWR meter registers very low SWR.  A KAT500 is doing
the antenna tuning after RF passes through the KPA500.  2. If I take the
KPA500 out of bypass into operating mode, output drops to zero, SWR goes
sky high, and KAT500 can't tune it.   Seems it must be a short of some
time that's somewhere in the amp circuit and not in the bypass path.  
Any idea where to start to trouble shooting this?  The strange thing is
the KPA500 worked FB for the first ten minutes of its life.

Tnxs for any suggestions.

73,

Carl
--
==============================
Carl Jón Denbow, N8VZ

17 Coventry Lane
Athens, Ohio 45701-3718
EM89wh

http://www.n8vz.com
[hidden email]
==============================
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[Carl Jón Denbow]

P.S.  The rig is a Kenwood TS-590s.

> Carl Jón Denbow <mailto:[hidden email]>
> Monday, July 01, 2013 9:01 PM
> OK, after Tim, M0AFJ, informed me that the amp needed to have fuses,
> and I dutifully installed same, everything seemed fine for a little
> while.  Thanks, Tim, for the heads up.  At that point I tried it on
> several different bands into a dummy load and into the ether and was
> getting 500 watts out.  Then, I decided to put a watt meter inline to
> get a more accurate assessment of wattage and instead I got really low
> output readings on several transmissions and then zero.  I then took
> the watt meter out of line and now I have the following phenomenon:  
> 1. In bypass mode I get out full wattage -- 45 watts from rig, but the
> KPA500 says it's 35.  The rig's SWR meter registers very low SWR.  A
> KAT500 is doing the antenna tuning after RF passes through the
> KPA500.  2. If I take the KPA500 out of bypass into operating mode,
> output drops to zero, SWR goes sky high, and KAT500 can't tune it.  
> Seems it must be a short of some time that's somewhere in the amp
> circuit and not in the bypass path.  Any idea where to start to
> trouble shooting this?  The strange thing is the KPA500 worked FB for
> the first ten minutes of its life.
>
> Tnxs for any suggestions.
>
> 73,
>
> Carl

--
==============================
Carl Jón Denbow, N8VZ

17 Coventry Lane
Athens, Ohio 45701-3718
EM89wh

http://www.n8vz.com
[hidden email]
==============================
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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