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K3 sudden loss of RF power output

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n0tt1

K3 sudden loss of RF power output

Hi Gents,

K3 sudden loss of RF power output:
I was operating the FD event over the weekend...had a nice
pileup going...I heard a "pop" in the headphones and discovered
that there was ZERO RF power output when there should have been
100 Watts. Receiver was OK and the radio was otherwise "acting"
normally as when switching from receive to transmit.
Circuit breaker not tripped.

I want to do some troubleshooting before (and if) I send the
radio to Elecraft. Per a Google search, this has happened
before to others and a bad Q8/Q9 and R66 on the RF board
might be suspect. Anything else on the list?

Thanks,
Charlie, N0TT
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Brett Howard

Re: K3 sudden loss of RF power output

I was the one that had a bad Q8/Q9 and R66 (actually the bad Q8/Q9 is
what creates the bad R66). Anyway when I had this issue the RX was
pretty severly affected as well. When I read your message I was
thinking it was the same problem that I'd had but the fact that your RX
seems ok makes me think it may be something else.

My RX was working it just seemed really quite quiet from what was
expected. Lemme know how your process goes... Being that I've had
something very similar happen I'm quite interested in how this goes for
you...

~Brett (KC7OTG)

On Wed, 2009-07-01 at 23:21 +0100, Missouri Guy wrote:

> Hi Gents,
>
> K3 sudden loss of RF power output:
> I was operating the FD event over the weekend...had a nice
> pileup going...I heard a "pop" in the headphones and discovered
> that there was ZERO RF power output when there should have been
> 100 Watts. Receiver was OK and the radio was otherwise "acting"
> normally as when switching from receive to transmit.
> Circuit breaker not tripped.
>
> I want to do some troubleshooting before (and if) I send the
> radio to Elecraft. Per a Google search, this has happened
> before to others and a bad Q8/Q9 and R66 on the RF board
> might be suspect. Anything else on the list?
>
> Thanks,
> Charlie, N0TT
> ______________________________________________________________
> 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

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Vic Goncharsky

Re: K3 sudden loss of RF power output

In reply to this post by n0tt1

Hi Charlie,You need to go backwards from the antenna connector to T/R switch then, to the final transistors, is there an idle current when you PTT? Then go to the driver stage etc... I am actually doing almost the same kind of repair now - The bias voltage in my VHF transistor 2m amp just disappeared and there are only 2 days left B4 the major VHF/UHF contest event of the year this weekend.
73 Vic US5WE/K1WE K3 #2907
--- On Wed, 7/1/09, Missouri Guy <[hidden email]> wrote:

From: Missouri Guy <[hidden email]>
Subject: [Elecraft] K3 sudden loss of RF power output
To: [hidden email]
Date: Wednesday, July 1, 2009, 10:21 PM

Hi Gents,

K3 sudden loss of RF power output:
I was operating the FD event over the weekend...had a nice
pileup going...I heard a "pop" in the headphones and discovered
that there was ZERO RF power output when there should have been
100 Watts. Receiver was OK and the radio was otherwise "acting"
normally as when switching from receive to transmit.
Circuit breaker not tripped.

I want to do some troubleshooting before (and if) I send the
radio to Elecraft. Per a Google search, this has happened
before to others and a bad Q8/Q9 and R66 on the RF board
might be suspect. Anything else on the list?

Thanks,
Charlie, N0TT
______________________________________________________________
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______________________________________________________________
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Philip Leonard WVØT

Re: K3 sudden loss of RF power output

In reply to this post by n0tt1

My K3 did the same thing. This is the 2nd year in a row I've lost
output power during Field Day. Not good.

Philip

Missouri Guy wrote:

Andrew Moore-3

Re: K3 sudden loss of RF power output

Some bits I don't need: All are assembled and unused:

EC1 enclosure - $30 shipped
EC2 enclosure - $45 shipped
AT1 step attenuator (41 dB, HF/VHF) - $35

Tek 2246 scope $400 used a couple hours after new-in-box, comes w/19-inch
rack mount

PayPal accepted.

Email off list
--Andrew
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