K3: ammeter display does not include 12 RCA acc skt?

[Stephen G4SJP]

Well, it's in the title really, but I was surprised to find that
turning the P3 off does not reduce the current reading on the K3
display (the P3 is powered by the 12v acc skt).  That's a pity as it
would be useful to see the load on that socket without using an
external ammeter.  Yes, I do have other 12V supplies etc etc..... :-)

I guess that's a hardware rather than a firmware issue?

73 Stephen G4SJP
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[wayne burdick]

Hi Stephen,

The aux 12 V output is not part of the current-monitored path. The  
main reason for the current monitor is to keep track of the health of  
the radio itself, so we take corrective or informative action in  
either RX or TX mode.

73,
Wayne
N6KR

On May 30, 2011, at 10:18 AM, Stephen Prior wrote:

> Well, it's in the title really, but I was surprised to find that
> turning the P3 off does not reduce the current reading on the K3
> display (the P3 is powered by the 12v acc skt).  That's a pity as it
> would be useful to see the load on that socket without using an
> external ammeter.  Yes, I do have other 12V supplies etc etc..... :-)
>
> I guess that's a hardware rather than a firmware issue?
>
> 73 Stephen G4SJP


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[Matt Zilmer]

Check the schematic.  The aux 12V is really "close" to the 12V input,
being dropped by one diode and a FET junction.  There's no shunt in
that leg.  No way to measure I to the 12V output.

matt W6NIA

On Mon, 30 May 2011 18:18:44 +0100, you wrote:

>Well, it's in the title really, but I was surprised to find that
>turning the P3 off does not reduce the current reading on the K3
>display (the P3 is powered by the 12v acc skt).  That's a pity as it
>would be useful to see the load on that socket without using an
>external ammeter.  Yes, I do have other 12V supplies etc etc..... :-)
>
>I guess that's a hardware rather than a firmware issue?
>
>73 Stephen G4SJP
>______________________________________________________________
>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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[Stephen G4SJP]

Thanks guys for the lightning speed answers.  Now to ask Icom about
something on my IC-703, wonder how long they will take to respond! :-)

73 Stephen

On 30 May 2011 18:22, Matt Zilmer <[hidden email]> wrote:

> Check the schematic.  The aux 12V is really "close" to the 12V input,
> being dropped by one diode and a FET junction.  There's no shunt in
> that leg.  No way to measure I to the 12V output.
>
> matt W6NIA
>
> On Mon, 30 May 2011 18:18:44 +0100, you wrote:
>
>>Well, it's in the title really, but I was surprised to find that
>>turning the P3 off does not reduce the current reading on the K3
>>display (the P3 is powered by the 12v acc skt).  That's a pity as it
>>would be useful to see the load on that socket without using an
>>external ammeter.  Yes, I do have other 12V supplies etc etc..... :-)
>>
>>I guess that's a hardware rather than a firmware issue?
>>
>>73 Stephen G4SJP
>>______________________________________________________________
>>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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[Matt Zilmer]

About 30,000x as long....

On Mon, 30 May 2011 18:25:15 +0100, you wrote:

>Thanks guys for the lightning speed answers.  Now to ask Icom about
>something on my IC-703, wonder how long they will take to respond! :-)
>
>73 Stephen
>
>On 30 May 2011 18:22, Matt Zilmer <[hidden email]> wrote:
>> Check the schematic.  The aux 12V is really "close" to the 12V input,
>> being dropped by one diode and a FET junction.  There's no shunt in
>> that leg.  No way to measure I to the 12V output.
>>
>> matt W6NIA
>>
>> On Mon, 30 May 2011 18:18:44 +0100, you wrote:
>>
>>>Well, it's in the title really, but I was surprised to find that
>>>turning the P3 off does not reduce the current reading on the K3
>>>display (the P3 is powered by the 12v acc skt).  That's a pity as it
>>>would be useful to see the load on that socket without using an
>>>external ammeter.  Yes, I do have other 12V supplies etc etc..... :-)
>>>
>>>I guess that's a hardware rather than a firmware issue?
>>>
>>>73 Stephen G4SJP
>>>______________________________________________________________
>>>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
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>
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[Bruce Beford-2]

I actually modified my K3 to do this back in August of last year. I wrote up
the details in a post you can read here:

 

http://elecraft.365791.n2.nabble.com/K3-switched-DC-output-jack-simple-mod-t
d5425993.html

 

Works great.

Bruce, N1RX

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