[Elecraft] K3 with subrx - intermittent main RX problem and pwr out

[Alan. G4GNX]

FWIW we thought that a relay was failing on our club's KAT500. I bought a 
new one from Elecraft and replaced it without thinking about it. They're 
quite cheap and it wasn't worth chancing an intermittent relay.
Whilst I was re-assembling the tuner, I discovered that the tag washer 
connecting Ant 1 to its screw terminal had developed a dry joint, which was 
the real cause of the intermittency. I don't know whether it was a 
manufacturing fault or someone had been heavy handed when assembling it.

It would be worth checking soldered joints and other connections before 
replacing a relay. You may need to use a magnifying glass as it may not show 
up on a meter test. Another thing to try is what we used to do as service 
technicians; use an aerosol freezer spray in small areas around the 
suspected area and possibly a hair dryer on a warm setting (not hot) and 
observe for changes under test.

73,

Alan. G4GNX

-----Original Message----- 
From: Victor Rosenthal 4X6GP
Sent: Thursday, May 4, 2017 3:07 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K3 with subrx - intermittent main RX problem and pwr 
out

Well, I had a relay fail on my KAT3 board. I don't remember which one.
Elecraft sent me a replacement. It wasn't hard to replace, but it happens.

73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
http://www.qsl.net/k2vco/

On 4 May 2017 16:46, Don Wilhelm wrote:
> Olaf,
>
> The relays used by Elecraft are quite reliable, so I suspect that is not
> a reasonable source of the problem.  In more than 12 years of repairing
> the Elecraft legacy gear (more than 1200 repairs), I have had to replace
> only a small handful of relays due to failure.  I have replaced several
> where the builder has distorted the case with a soldering iron.
>
> I would double and triple check the SUBIN and SUBOUT connectors.  A
> connector failure is much more likely than a relay failure.
>
> You might contact K3support to see if they have encountered a situation
> like yours before.
>
> 73,
> Don W3FPR
>
> On 5/4/2017 3:31 AM, la3rk wrote:
>> I have a K3 approx 8 years old. Fully equipped with subrx, 100W PA,
>> antenna
>> tuner and in/out module.
>>
>> When I connect the subrx, the main rx sometimes loses signal and at
>> the same
>> time power out goes to zero.