[Elecraft] Newly Built KPA500 Acting Strange

[Carl Jón Denbow]

P.S.  The rig is a Kenwood TS-590s.

> Carl Jón Denbow <mailto:carl at n8vz.com>
> 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

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Carl Jón Denbow, N8VZ

17 Coventry Lane
Athens, Ohio 45701-3718
EM89wh

http://www.n8vz.com
carl at n8vz.com
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