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K3 abruptly shuts off during CW transmission

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K4SC

K3 abruptly shuts off during CW transmission

After nearly two years of trouble free operation, I have developed a repeatable problem. While transmitting on 40 meter CW on my usual antenna the K3 suddenly shuts down. When I repower it, it comes back up fine, but has shifted frequency by about 1.5 kHz. This is occuring during relatively short transmissions. Power was at 100 watts and swr was about 1.5:1. I tried turning power down to 75 watts and it repeated. I then switched to a dummy load and it happens again; as I said it is definitely repeatable. I even updated the firmware, no joy! Any thoughts. I operated cw mostly so I can't say if this is also occuring on SSB.

Thanks, Chuck K4SC South Carolina

Dennis Moore

Re: K3 abruptly shuts off during CW transmission

Have your checked your power supply connections, or tried another power
supply?

On 8/14/2011 5:45 PM, K4SC wrote:
> After nearly two years of trouble free operation, I have developed a
> repeatable problem. While transmitting on 40 meter CW on my usual antenna
> the K3 suddenly shuts down.

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Mercury

Re: K3 abruptly shuts off during CW transmission

In reply to this post by K4SC

I had this happen once and it turned out to be the Astron LM-35 power supply I was using. It did not repeat on another supply I had. Still haven't looked into repairing the Astron, but understand it is not an uncommon failure.

Will, AI4VE
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Augie "Gus" Hansen

Re: K3 abruptly shuts off during CW transmission

> I had this happen once and it turned out to be the Astron LM-35 power supply I was using. It did not repeat on another supply I had. Still haven't looked into repairing the Astron, but understand it is not an uncommon failure.

I had a similar failure with an Astron 18 amp supply. It would work
well for a while then cut out under load intermittently. The problem
was a wire connected to the circuit board that was making mechanical
contact, but had never be soldered. After soldering the wire, I
checked all the other solder connections and touched up a couple
that looked marginal. All has been well since.

Gus Hansen
KB0YH

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Lou Kolb

Re: K3 abruptly shuts off during CW transmission

In reply to this post by K4SC

I'm having a similar problem with k3 4290. I have qrq mode turned on but
when I engage the RIT which turns QRQ mode off and then transmit, the rig
shuts down. It also comes back on a different frequency when I power it
back up. If I leave the RIT off, it doesn't happen. I thought it might be
firmware related and had been meaning to reinstall version 436. Then, 439
was released so I just upgraded to it figuring that might solve the problem
but no joy. I'm at a loss to explain this so any thoughts would be welcome.
Thanks. lou WA3MIX
----- Original Message -----
From: "K4SC" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, August 14, 2011 8:45 PM
Subject: [Elecraft] K3 abruptly shuts off during CW transmission

> After nearly two years of trouble free operation, I have developed a
> repeatable problem. While transmitting on 40 meter CW on my usual antenna
> the K3 suddenly shuts down. When I repower it, it comes back up fine, but
> has shifted frequency by about 1.5 kHz. This is occuring during
> relatively
> short transmissions. Power was at 100 watts and swr was about 1.5:1. I
> tried turning power down to 75 watts and it repeated. I then switched to
> a
> dummy load and it happens again; as I said it is definitely repeatable. I
> even updated the firmware, no joy! Any thoughts. I operated cw mostly so
> I
> can't say if this is also occuring on SSB.
>
> Thanks, Chuck K4SC South Carolina
>
> --
> View this message in context:
> http://elecraft.365791.n2.nabble.com/K3-abruptly-shuts-off-during-CW-transmission-tp6685970p6685970.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

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Guy, K2AV

Re: K3 abruptly shuts off during CW transmission

The going back to the "last saved" frequency is a dead giveaway that
the power has been EXTERNALLY removed or glitched without the benefit
of manual power off (which allows K3 to go through all its "save
stuff" shutdown routines). This will bring you up on the previous
frequency. If the previous operation was a different mode, it will go
to that mode as well.

Don't let the lack of an obvious connection to RIT off get you onto a
tangent. Fix the problem with the power wiring or power supply and
see what is left afterwards. You may never be able to explain why it
happened with RIT. I could guess that turning on RIT causes a spike
of K3 CPU power consumption to do all the processing crap needed to
turn on RIT, and is the straw that broke the camel's back. But I
don't know that, and it doesn't matter.

The power problem could be those power pins (that are now gold
anodized) going bad. You can read about that problem on the Elecraft
site.

73, Guy.

On Sun, Aug 14, 2011 at 9:39 PM, Lou Kolb <[hidden email]> wrote:

> I'm having a similar problem with k3 4290. I have qrq mode turned on but
> when I engage the RIT which turns QRQ mode off and then transmit, the rig
> shuts down. It also comes back on a different frequency when I power it
> back up. If I leave the RIT off, it doesn't happen. I thought it might be
> firmware related and had been meaning to reinstall version 436. Then, 439
> was released so I just upgraded to it figuring that might solve the problem
> but no joy. I'm at a loss to explain this so any thoughts would be welcome.
> Thanks. lou WA3MIX
> ----- Original Message -----
> From: "K4SC" <[hidden email]>
> To: <[hidden email]>
> Sent: Sunday, August 14, 2011 8:45 PM
> Subject: [Elecraft] K3 abruptly shuts off during CW transmission
>
>
>> After nearly two years of trouble free operation, I have developed a
>> repeatable problem. While transmitting on 40 meter CW on my usual antenna
>> the K3 suddenly shuts down. When I repower it, it comes back up fine, but
>> has shifted frequency by about 1.5 kHz. This is occuring during
>> relatively
>> short transmissions. Power was at 100 watts and swr was about 1.5:1. I
>> tried turning power down to 75 watts and it repeated. I then switched to
>> a
>> dummy load and it happens again; as I said it is definitely repeatable. I
>> even updated the firmware, no joy! Any thoughts. I operated cw mostly so
>> I
>> can't say if this is also occuring on SSB.
>>
>> Thanks, Chuck K4SC South Carolina
>>
>> --
>> View this message in context:
>> http://elecraft.365791.n2.nabble.com/K3-abruptly-shuts-off-during-CW-transmission-tp6685970p6685970.html
>> Sent from the Elecraft mailing list archive at Nabble.com.
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

K4SC

Re: K3 abruptly shuts off during CW transmission

Power supply appears to be the problem. It is an Icom PS-125 that was a "gimmee" when I got my previous rig, an IC-746PRO. The problem kept repeating even after I reseated the power pole connectors in the K3 rear apron. I then substituted a switching supply I have for my Kenwood TS-480HX and had the radio transmitting a CQ loop into a dummy load for about two hours and it just kept going and going and ...