[Elecraft] KPA1500 problem

[RIchard Williams]

Roy,
The very first thing you do is attach a dummy load to the antenna jack on the back of he amp and isolate the problem to the amp or feedline and/or antenna.  If you don't have one, you should purchase one right away.
I have seen the type of fault many times, and a good percentage of the it is not the amp.  One fault I have seen more than once is using high power into a load with high SWR.  That develops very high voltages on the coax, and it arcs through.  Once that happens, you need to find the issue with the antenna and replace the coax.
Dick, K8ZTT
Sent from Yahoo Mail on Android 
 
  On Mon, Dec 31, 2018 at 5:56, Roy Koeppe<k6xk at ncn.net> wrote:   

" My KPA1500 (s/n 121) has developed a problem:
When applying power (15-20W) from the K3 to the amp, it immediately faults 
to:low gain fault ratio 3 (sometimes ratio 2 to ratio 6). The SWR indicator 
shows high SWR as the amp faults. 100w only from exciter will cause ATU to 
tune to 1:1 but when amp is switched on, it immediately faults as above. 
Looked through archives and manual. No mention of this particular fault. Any 
ideas would be appreciated."

I have had that exact same thing happen, and tracked it down to bad WW2 
transmitting micas in my 160M Omega-match at the antenna feedpoint. 
Something is likely breaking down, as someone else just commented. Luck & 
73,

Roy    K6XK 


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