[Elecraft] KPA1500 RELIABILITY

[Dr. William J. Schmidt]

My KPA1500 just blew up for the third time... gonna go back again.  Forced
us to run LP in CQWW this weekend as it exploded just two days ahead of the
contest.  No reason for the explosion that I can tell... radio worked fine
on the antenna system without the amp after the explosion.

Previously it went back for:
1.  MeanWell Power Supply failure.  (Hey, it happens).
2.  Blew up the blocking capacitors in the final output circuit (teeny
suckers, no reason for it).

This time I got a hard failure/low gain so figure it's gonna be final
transistors.  Thinking of going back to tube amps because they are much more
forgiving!


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
VP2EHZ


email:  bill at wjschmidt.com


-----Original Message-----
From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On
Behalf Of john at kk9a.com
Sent: Sunday, October 30, 2022 10:44 AM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] KPA1500 RELIABILITY

Is there a common component failure with this KPA1500 amp or does something
different break every time?  Is there a certain mode, power level or type of
antenna/feedline that causes failures?  I also monitor the SPE Expert list
and some people have multiple LDMOS failures while others have no issues
ever. N4ZR posted a similar question two months ago when someone else had
multiple LDMOS failures and I did not see any responses. 
http://mailman.qth.net/pipermail/elecraft/2022-August/290628.html

GL,
John KK9A
  

W3AB wrote:

I don't have one but I do have access to one. It is making UPS rich going
back and forth. Is there a reliability issue with these amps?

---
73 de W3AB/GEO


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