K1 no output power

[Lorenz Koestler]

Hi

I build a K1 (80m, 20m) during the last days and had a lot of fun! The
manual is just awesome and I am looking forward to make my first qso
with it.

Now I have a problem with the tramitter. That is why I joined this list
and I was very glad to see, that there is much activity.

The rx alignment went well and the resistance and voltage checks of the
tx part are all fine.

When I first started the tune mode on 80m with 2 watts, it shows me
somewhat like 1.7, Q7 became quite hot and something started smelling. I
was not able to read the current consumption before I disconnected the
source.

After double-checking all resistor values, the orientation of all diodes
and ICs and the transformers, I tried it again.

But now, regardless on what Out-Pwr and Band I choose, the display shows
"P0.1" in tune mode. I can hear a very weak tone in the K3 standing next
to the K1. The current consumption is at about: 60mA rx, 200mA tx

I cant see any cold solder connections nor bridges.

So I guess I burned Q7 somehow. Any idea what I can do or what went
wrong here?

How can I test a 2SC1969 and what do I have to check, to make sure, I
don't just burn a new one?

Many tnx fer ur help and best 73 de Lorenz / HB9TYU (Zurich, Switzerland)

--
Lorenz Koestler <[hidden email]> / HB9TYU
PingMe: https://pingen.com/*lorenz
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[Don Wilhelm-4]

  Lorenz,

Check the core that was used for T4,  There were a few kits which were
shipped a few weeks ago that contained a T50-10 powdered iron core
instead of the FT50-43 ferrite core - I happened to build one of those

The incorrect core has black paint while the correct ferrite core has a
slightly dark gray appearance.  If you ordered the KAT1, look at the
ferrite core shipped with it for visual comparison of the appearance
(the size will be smaller).

There were only a few kits shipped with this error and when I discovered
the problem, the kind people at Elecraft checked all the kits in stock
and found them to be correct.  We concluded that this was a one-off
error, but apparently there were a few more.

If the core was incorrect in your K1, contact [hidden email] with a
brief explanation and you should receive a new core and a new PA
transistor under the terms of the parts warranty.

73,
Don W3FPR

On 10/17/2010 4:39 PM, Lorenz Koestler wrote:

> Hi
>
> I build a K1 (80m, 20m) during the last days and had a lot of fun! The
> manual is just awesome and I am looking forward to make my first qso
> with it.
>
> Now I have a problem with the tramitter. That is why I joined this list
> and I was very glad to see, that there is much activity.
>
> The rx alignment went well and the resistance and voltage checks of the
> tx part are all fine.
>
> When I first started the tune mode on 80m with 2 watts, it shows me
> somewhat like 1.7, Q7 became quite hot and something started smelling. I
> was not able to read the current consumption before I disconnected the
> source.
>
> After double-checking all resistor values, the orientation of all diodes
> and ICs and the transformers, I tried it again.
>

______________________________________________________________
Elecraft mailing list
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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

[hjallis]

Hi,
I just finished building K1 #2929 (80/20) with the wrong toroid. I discovered that just after I had mounted it. I've contacted Gary at Elecraft and he will send me a new one. But I could'nt wait to try it with the wrong toroid and for me the rig works fantastic. Have no problem with excessive current drain on transmit. Worked into Senegal, Africa yesterday on 20m under poor condition. I hardly could hear him and there is nothing wrong with the rx because I have compared it with my TenTec OmniVI Plus and it is just as sensitive. I don't know if I will even bother to change the toroid when it eventually arrives.

73 de la4xx
Hjalmar

[hjallis]

Hi again,
Well, it worked for two weeks. No it doesn't. I received a new core last saturday together with the RF Choke RFC8 which was missing in my set. Så far I've used a jumper instead of the RFC8. I mounted the RFC8, but didn't take my time to change the core. After that I noticed that the side panel got very hot during a QSO just where the Q7 was mounted. I'm not sure if that  happened prior to the RFC8 mount, but after a few more QSO's the transmitter died. Now Q7 gets very hot even in receive mode and there is a short between the collector and ground. Gary has already sent me a replacement so hopefully I'll have it here in a few days.
73 de Hjalmar
la4xx