K1 - No output

[stan levandowski]

I just finished  FOUR BAND K1 #2994.  Receives FB; all functions appear
to work. NB and KAT not yet built/installed.  Sensitivity seem very good
but a LOT noisier than either K2 or K3.

However, the transmitted signal is very weak (although of excellent
quality and on frequency).  Going into a dummy load through my analog
wattmeter shows no RF output so it's probably less than .1 W.  Same deal
on all bands.

The initial checkout voltages and resistances are within the specified
ranges.

I'm just about convinced that the Q7 PA transistor is bad although the
E-B-C voltages tested out OK and it is NOT shorted to ground.

One more thing - Transformer T4 (all my toroids were wound by
TheToroidGuy) seems "interesting" . The actual resistances of 1-3 and
2-4 (on a Fluke DMM) show -0.01 ohms whiich seems to agree with the
manual's requirement that the measurement be no greater than 5 ohms.
The schematic  shows 2-4 connected to 1-3 so apparently this continuity
is all OK?

I'm stumped. Either the problem is not at all obvious or so very obvious
I'm looking right across it.

  Before I start the long process of signal tracing I thought I'd throw
my problem out to the List and see if anyone has any quick ideas.

(P.S. - My test equipment is limited to a DMM, an antenna analyzer, and
a homemade RF probe.)

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[Don Wilhelm-4]

Stan,

Your homemade RF probe should suffice for doing Transmit Signal Tracing
as indcicated in the back (appendix E) of the manual.  Find the stage
where the RF voltages is substantially less than the expected value and
you have found the source of your failure.

Once we know that failure point, we should be able o help you in
identifying he component failure point.

73,
Don W3FPR

On 5/17/2011 3:09 PM, stan levandowski wrote:

> I just finished  FOUR BAND K1 #2994.  Receives FB; all functions appear
> to work. NB and KAT not yet built/installed.  Sensitivity seem very good
> but a LOT noisier than either K2 or K3.
>
> However, the transmitted signal is very weak (although of excellent
> quality and on frequency).  Going into a dummy load through my analog
> wattmeter shows no RF output so it's probably less than .1 W.  Same deal
> on all bands.
>
> The initial checkout voltages and resistances are within the specified
> ranges.
>
> I'm just about convinced that the Q7 PA transistor is bad although the
> E-B-C voltages tested out OK and it is NOT shorted to ground.
>
> One more thing - Transformer T4 (all my toroids were wound by
> TheToroidGuy) seems "interesting" . The actual resistances of 1-3 and
> 2-4 (on a Fluke DMM) show -0.01 ohms whiich seems to agree with the
> manual's requirement that the measurement be no greater than 5 ohms.
> The schematic  shows 2-4 connected to 1-3 so apparently this continuity
> is all OK?
>
> I'm stumped. Either the problem is not at all obvious or so very obvious
> I'm looking right across it.
>
>    Before I start the long process of signal tracing I thought I'd throw
> my problem out to the List and see if anyone has any quick ideas.
>
> (P.S. - My test equipment is limited to a DMM, an antenna analyzer, and
> a homemade RF probe.)
>
> ______________________________________________________________
> 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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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html