Elecraft

K3 - KEY OUT problem

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N4ZR

K3 - KEY OUT problem

Thanks to everyone who responded. I've now written to Elecraft Support,
and anticipate that it will have to go back to the mother ship.

--

73, Pete N4ZR
Check out the Reverse Beacon Network
at <http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

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donovanf

Re: K3 - KEY OUT problem

Hi Pete,

Perhaps more important: how did this unusual failure occur?
Unless you can figure this out with a reasonable degree of certainty,
you're radio is likely to make multiple trips for repair.

One possibility is that you connected a relay to the KEY OUT
connector, but the relay didn't have a snubber diode across its coil.
That could cause enough of a spike to damage your radio.

Another possibility is that you plugged the incorrect cable into the
K3 and excess voltage on that cable damaged your radio.

Good luck!

73
Frank
W3LPL

----- Original Message -----

From: "N4ZR" <[hidden email]>
To: "Elecraft List" <[hidden email]>
Sent: Saturday, December 28, 2019 3:57:01 PM
Subject: [Elecraft] K3 - KEY OUT problem

Thanks to everyone who responded. I've now written to Elecraft Support,
and anticipate that it will have to go back to the mother ship.

--

73, Pete N4ZR
Check out the Reverse Beacon Network
at <http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
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donovanf

Re: K3 - KEY OUT problem

Pete,

I've never had any reason to look at the KEY OUT circuit before, but
it uses a very robust IRF1630 power MOSFET, rated at 200 volts
and 10 amps. Very robust indeed, its no wonder I've never had a
failure. Its not a surface mount device, its a TO220 package.

73
Frank
W3LPL

----- Original Message -----

From: [hidden email]
To: [hidden email]
Sent: Saturday, December 28, 2019 4:43:05 PM
Subject: Re: [Elecraft] K3 - KEY OUT problem

Hi Pete,

Perhaps more important: how did this unusual failure occur?
Unless you can figure this out with a reasonable degree of certainty,
you're radio is likely to make multiple trips for repair.

One possibility is that you connected a relay to the KEY OUT
connector, but the relay didn't have a snubber diode across its coil.
That could cause enough of a spike to damage your radio.

Another possibility is that you plugged the incorrect cable into the
K3 and excess voltage on that cable damaged your radio.

Good luck!

73
Frank
W3LPL

----- Original Message -----

From: "N4ZR" <[hidden email]>
To: "Elecraft List" <[hidden email]>
Sent: Saturday, December 28, 2019 3:57:01 PM
Subject: [Elecraft] K3 - KEY OUT problem

Thanks to everyone who responded. I've now written to Elecraft Support,
and anticipate that it will have to go back to the mother ship.

--

73, Pete N4ZR
Check out the Reverse Beacon Network
at <http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
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
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ng7m

Re: K3 - KEY OUT problem

In reply to this post by N4ZR

Pete, just saw your question on the PTT OUT not working for you. I had an
issue with this back in 2016... I can't remember what I did, but it wasn't
smart and it was my fault... Anyway, I let the smoke/metal out of the IRFI630G
that is used on the PPT out. It's beefy and can take a lot of abuse, but I
still managed to destroy it. Anyway, it's an easy replacement and saved me
from shipping my K3 back to Elecraft. Total operator error in my
situation... maybe attached 12v to the PTT out? Again, I can't remember.

Here is a picture of what my damaged MOSFET looked like at the time... see
the crack and leakage ;)

http://www.nc7j.com/pa/main.php?cmd=imageview&var1=NG7M%2FRadios%2FK3%2FSmokedKeyOutIRFI630G%2FIRFI630GFried.JPG

And here is the Mouser part I ordered to replace it:

https://www.mouser.com/ProductDetail/Vishay-Siliconix/IRFI630GPBF?qs=%2Fha2pyFaduhSYcFgYMU8ma88%2Fb96%2Fl4SGKWFSYSWEuEDdoRAAyNpCg==

Here is the schematic link:
https://ftp.elecraft.com/K3/Manuals%20Downloads/K3_Schematics_Jun_2010.pdf

Search for IRFI630 in the PDF, you will find it straight away... and I
don't remember it being tough to expose the damaged mosfet and replace
it...

Max NG7M

On Sat, Dec 28, 2019 at 8:57 AM N4ZR <[hidden email]> wrote:

> Thanks to everyone who responded. I've now written to Elecraft Support,
> and anticipate that it will have to go back to the mother ship.
>
> --
>
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at <http://reversebeacon.net>, now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

--
M. George
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ng7m

Re: K3 - KEY OUT problem

Bob N7WY motivated me to provide a few more details on the KEY OUT
mosfet/Q3/IRFI630 replacement. I took the bottom off my K3 to show the
location of the IRFI630 on the bottom of the PCB. It was a little more
tricky than I remembered, so you will need to access the main PCB from the
top of the K3 by removing the KIO3 board and the IO board that has the IF
output. I did the replacement without removing the back panel which would
have been very painful. Again, I do remember being able to do this without
a major disassembly. I de-soldered from the bottom of the PCB and pulled
and replaced the IRFI630 from the top. It was tight, but it sure beat
sending the K3 back to Elecraft and you can do a clean job if you are
careful.

Here are some new pictures that I just took
<http://www.nc7j.com/pa/main.php?cmd=album&var1=NG7M%2FRadios%2FK3%2FSmokedKeyOutIRFI630G%2F>
and annotated with more details of the location of Q3 along with a snippet
from the Elecraft Schematic where Q3 is located. Your mileage may vary
based on your re-work skills but I wouldn't consider this a difficult
replacement... medium effort at worst. When in doubt, send your radio in,
but it's not rocket science:

Updated Pictures:
http://www.nc7j.com/pa/main.php?cmd=album&var1=NG7M%2FRadios%2FK3%2FSmokedKeyOutIRFI630G%2F

Good Luck!

Max NG7M

On Sat, Dec 28, 2019 at 10:20 AM M. George <[hidden email]>
wrote:

> Pete, just saw your question on the PTT OUT not working for you. I had an
> issue with this back in 2016... I can't remember what I did, but it wasn't
> smart and it was my fault... Anyway, I let the smoke/metal out of the IRFI630G
> that is used on the PPT out. It's beefy and can take a lot of abuse, but I
> still managed to destroy it. Anyway, it's an easy replacement and saved me
> from shipping my K3 back to Elecraft. Total operator error in my
> situation... maybe attached 12v to the PTT out? Again, I can't remember.
>
> Here is a picture of what my damaged MOSFET looked like at the time... see
> the crack and leakage ;)
>
>
> http://www.nc7j.com/pa/main.php?cmd=imageview&var1=NG7M%2FRadios%2FK3%2FSmokedKeyOutIRFI630G%2FIRFI630GFried.JPG
>
> And here is the Mouser part I ordered to replace it:
>
>
> https://www.mouser.com/ProductDetail/Vishay-Siliconix/IRFI630GPBF?qs=%2Fha2pyFaduhSYcFgYMU8ma88%2Fb96%2Fl4SGKWFSYSWEuEDdoRAAyNpCg==
>
> Here is the schematic link:
> https://ftp.elecraft.com/K3/Manuals%20Downloads/K3_Schematics_Jun_2010.pdf
>
> Search for IRFI630 in the PDF, you will find it straight away... and I
> don't remember it being tough to expose the damaged mosfet and replace
> it...
>
> Max NG7M
>
> On Sat, Dec 28, 2019 at 8:57 AM N4ZR <[hidden email]> wrote:
>
>> Thanks to everyone who responded. I've now written to Elecraft Support,
>> and anticipate that it will have to go back to the mother ship.
>>
>> --
>>
>> 73, Pete N4ZR
>> Check out the Reverse Beacon Network
>> at <http://reversebeacon.net>, now
>> spotting RTTY activity worldwide.
>> For spots, please use your favorite
>> "retail" DX cluster.
>>
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
>
>
>
> --
> M. George
>