Re: KPA500 No Power Output

Richard Smith <ku4nz01@...>

Love my Acom 1000.  I keep  K3S at 35 watts, giving me @650 out on amp.   I never run max.  RAS KU4NZ

On Apr 3, 2020, at 8:06 PM, Christopher Scibelli via <nu1oscar@...> wrote:

I've had tube amps for the 30+ years I've been a ham.  I own an Alpha 8410 and a Heathkit SB-1000.  I built the Heathkit back in 1988 and it works like it is new.  Pretty sure it's the same as an Al-80B by Ameritron. I wouldn't want to buy it from MFJ but the design is solid.  The ham who designed it is very well known but I'm too tired to recall his call.  Pretty sure somebody in this forum knows who I'm referring to.

Best of luck and 73,

Chris  NU1O

-----Original Message-----
From: Jeff Clarke <ku8e@...>
To: Elecraft-K3 <>
Sent: Fri, Apr 3, 2020 8:48 pm
Subject: Re: [Elecraft-K3] KPA500 No Power Output

I've owned this amp for maybe 5 years and this is the first time I've had an issue. I was only running about 300 watts on FT8. When I use it in a contest I am very conservative and run 500 watts max.If you have a flat SWR on your antenna you can get it up to around 700 watts if you want. BTW this problem is occurring on all the bands. I'm thinking it's some kind of T/R relay failure because the way the SWR is acting when you put it in OPER. It's reading "--" and then jumps back and forth to 99:1. In standby it's just fine. 

It's been a real pain that the KPA500 always trips when you get near a 2:1 SWR and you have to reset it all the time. I've been thinking about buying another amp for awhile because of that. I ordered an Acom 1000 today. That will be my main amp with the KPA500 as a backup after I get it repaired. That might be awhile before I can get the KPA500 repaired because the reply I got from Elecraft says they aren't doing RSA's right now because of COVID-19.


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