K3 Voltmeter calibration ...

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K3 Voltmeter calibration ...

Joe Subich, W4TV-4

OK, I'm sure I am overlooking something simple but I can not find
(or remember) how to calibrate the voltage display in the K3.

I had to repair one of my Astron RS-35A power supplies for the first
time in 30 years (one of the diodes shorted) and when I put it back on
line I decided to double check the K3 Volts display against the actual
output of the supply.  The K3 is reading about 0.2V less than the
supply voltage.

I've been over both the K3 Owner's Manual and the K3 Assembly
Instructions but can't find any reference to calibrating the voltage
display.

73,

    ... Joe, W4TV

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Re: K3 Voltmeter calibration ...

Robert Nobis - N7RJN
Joe,

How long is your power cable from the RS-35A to your K3, and what gauge wire is used?  You could easily drop 0.2 volts in the cable depending how long it is and the gauge of the wire.

73,


Bob Nobis - N7RJN
[hidden email]


> On Nov 24, 2015, at 08:06, Joe Subich, W4TV <[hidden email]> wrote:
>
>
> OK, I'm sure I am overlooking something simple but I can not find
> (or remember) how to calibrate the voltage display in the K3.
>
> I had to repair one of my Astron RS-35A power supplies for the first
> time in 30 years (one of the diodes shorted) and when I put it back on
> line I decided to double check the K3 Volts display against the actual
> output of the supply.  The K3 is reading about 0.2V less than the
> supply voltage.
>
> I've been over both the K3 Owner's Manual and the K3 Assembly
> Instructions but can't find any reference to calibrating the voltage
> display.
>
> 73,
>
>   ... Joe, W4TV
>
> ______________________________________________________________
> 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]
>

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Re: K3 Voltmeter calibration ...

Michael Blake
In reply to this post by Joe Subich, W4TV-4
Joe, is there not at least one diode junction or solid state switch in series with the input power inside the K3?

Michael Blake - K9JRI




> On Nov 24, 2015, at 10:06 AM, Joe Subich, W4TV <[hidden email]> wrote:
>
>
> OK, I'm sure I am overlooking something simple but I can not find
> (or remember) how to calibrate the voltage display in the K3.
>
> I had to repair one of my Astron RS-35A power supplies for the first
> time in 30 years (one of the diodes shorted) and when I put it back on
> line I decided to double check the K3 Volts display against the actual
> output of the supply.  The K3 is reading about 0.2V less than the
> supply voltage.
>
> I've been over both the K3 Owner's Manual and the K3 Assembly
> Instructions but can't find any reference to calibrating the voltage
> display.
>
> 73,
>
>   ... Joe, W4TV
>
> ______________________________________________________________
> 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]

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Re: K3 Voltmeter calibration ...

Joe Subich, W4TV-4
In reply to this post by Robert Nobis - N7RJN

> You could easily drop 0.2 volts in the cable depending how long it
> isand the gauge of the wire.

Not in six feet of #10 wire at 1.5A.  Even if it were #12 the voltage
drop should be less than 0.03V (1.62 Ohms/1000 feet for #12).

73,

    ... Joe, W4TV


On 11/24/2015 10:39 AM, Robert Nobis wrote:

> Joe,
>
> How long is your power cable from the RS-35A to your K3, and what gauge wire is used?  You could easily drop 0.2 volts in the cable depending how long it is and the gauge of the wire.
>
> 73,
>
>
> Bob Nobis - N7RJN
> [hidden email]
>
>
>> On Nov 24, 2015, at 08:06, Joe Subich, W4TV <[hidden email]> wrote:
>>
>>
>> OK, I'm sure I am overlooking something simple but I can not find
>> (or remember) how to calibrate the voltage display in the K3.
>>
>> I had to repair one of my Astron RS-35A power supplies for the first
>> time in 30 years (one of the diodes shorted) and when I put it back on
>> line I decided to double check the K3 Volts display against the actual
>> output of the supply.  The K3 is reading about 0.2V less than the
>> supply voltage.
>>
>> I've been over both the K3 Owner's Manual and the K3 Assembly
>> Instructions but can't find any reference to calibrating the voltage
>> display.
>>
>> 73,
>>
>>    ... Joe, W4TV
>>
>> ______________________________________________________________
>> 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]
>>
>
>
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Re: K3 Voltmeter calibration ...

Joe Subich, W4TV-4
In reply to this post by Michael Blake

It matters not if there is a series diode.  The Voltmeter should
be calibrated to the input power.  I remember that being the case
when I assembled my first K3.

73,

    ... Joe, W4TV


On 11/24/2015 11:02 AM, Michael Blake wrote:

> Joe, is there not at least one diode junction or solid state switch in series with the input power inside the K3?
>
> Michael Blake - K9JRI
>
>
>
>
>> On Nov 24, 2015, at 10:06 AM, Joe Subich, W4TV <[hidden email]> wrote:
>>
>>
>> OK, I'm sure I am overlooking something simple but I can not find
>> (or remember) how to calibrate the voltage display in the K3.
>>
>> I had to repair one of my Astron RS-35A power supplies for the first
>> time in 30 years (one of the diodes shorted) and when I put it back on
>> line I decided to double check the K3 Volts display against the actual
>> output of the supply.  The K3 is reading about 0.2V less than the
>> supply voltage.
>>
>> I've been over both the K3 Owner's Manual and the K3 Assembly
>> Instructions but can't find any reference to calibrating the voltage
>> display.
>>
>> 73,
>>
>>    ... Joe, W4TV
>>
>> ______________________________________________________________
>> 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]
>
>
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Re: K3 Voltmeter calibration ...

Fred Townsend-2
In reply to this post by Joe Subich, W4TV-4
Joe check your schematic and you will see there is both a polyfuse and a
diode in series with the K3 front panel. The 100w PA pulls off its current
ahead of the fuse and diode so using the front panel is not indicative of
the voltage of the current going to power amp. Hang a voltmeter on the APP
if you want accuracy. Incidentally the polyfuse will permanently change
cold value after interrupting for the first time so there is another
variable.
73
Fred, AE6QL

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Joe
Subich, W4TV
Sent: Tuesday, November 24, 2015 9:31 AM
To: Robert Nobis; Elecraft
Subject: Re: [Elecraft] K3 Voltmeter calibration ...


> You could easily drop 0.2 volts in the cable depending how long it
> isand the gauge of the wire.

Not in six feet of #10 wire at 1.5A.  Even if it were #12 the voltage drop
should be less than 0.03V (1.62 Ohms/1000 feet for #12).

73,

    ... Joe, W4TV


On 11/24/2015 10:39 AM, Robert Nobis wrote:
> Joe,
>
> How long is your power cable from the RS-35A to your K3, and what gauge
wire is used?  You could easily drop 0.2 volts in the cable depending how
long it is and the gauge of the wire.

>
> 73,
>
>
> Bob Nobis - N7RJN
> [hidden email]
>
>
>> On Nov 24, 2015, at 08:06, Joe Subich, W4TV <[hidden email]> wrote:
>>
>>
>> OK, I'm sure I am overlooking something simple but I can not find (or
>> remember) how to calibrate the voltage display in the K3.
>>
>> I had to repair one of my Astron RS-35A power supplies for the first
>> time in 30 years (one of the diodes shorted) and when I put it back
>> on line I decided to double check the K3 Volts display against the
>> actual output of the supply.  The K3 is reading about 0.2V less than
>> the supply voltage.
>>
>> I've been over both the K3 Owner's Manual and the K3 Assembly
>> Instructions but can't find any reference to calibrating the voltage
>> display.
>>
>> 73,
>>
>>    ... Joe, W4TV
>>
>> ______________________________________________________________
>> 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]
>>
>
>
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Re: K3 Voltmeter calibration ...

Brian Broggie-2
In reply to this post by Joe Subich, W4TV-4
Joe, if you just want to make the K3's voltmeter match your "known good"
reference meter, you need to adjust the "ADC REF" value.

Go into the CONFIG menu, set Tech mode "On", then go to the "ADC REF"
setting.  Note what it is before changing anything, in case this
adjustment affects anything else adversely.  Adjust the ADC REF value to
cause the voltmeter display to read the value you want. You will need to
go in and out of the menu display to see the results (kinda clumsy).

Again, this adjustment may affect other measurements, so an accurate K3
voltmeter may not be that important after all.

73,
Brian, W6FVI

On 11/24/2015 9:32 AM, Joe Subich, W4TV wrote:

>
> It matters not if there is a series diode.  The Voltmeter should
> be calibrated to the input power.  I remember that being the case
> when I assembled my first K3.
>
> 73,
>
>    ... Joe, W4TV
>
>
> On 11/24/2015 11:02 AM, Michael Blake wrote:
>> Joe, is there not at least one diode junction or solid state switch
>> in series with the input power inside the K3?
>>
>> Michael Blake - K9JRI
>>
>>
>>
>>
>>> On Nov 24, 2015, at 10:06 AM, Joe Subich, W4TV <[hidden email]>
>>> wrote:
>>>
>>>
>>> OK, I'm sure I am overlooking something simple but I can not find
>>> (or remember) how to calibrate the voltage display in the K3.
>>>
>>> I had to repair one of my Astron RS-35A power supplies for the first
>>> time in 30 years (one of the diodes shorted) and when I put it back on
>>> line I decided to double check the K3 Volts display against the actual
>>> output of the supply.  The K3 is reading about 0.2V less than the
>>> supply voltage.
>>>
>>> I've been over both the K3 Owner's Manual and the K3 Assembly
>>> Instructions but can't find any reference to calibrating the voltage
>>> display.
>>>
>>> 73,
>>>
>>>    ... Joe, W4TV
>>>
>>> ______________________________________________________________
>>> 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]
>>
>>
> ______________________________________________________________
> 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]
>

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Re: K3 Voltmeter calibration ...

Joe Subich, W4TV-4
In reply to this post by Fred Townsend-2

Fred,

Diode, polyfuse, etc. does not matter.  There should be a calibration
routine so it can be set correctly.  I remember setting it when this
K3 was assembled but can not find the procedure in the current manuals.

What is the calibration procedure?


73,

    ... Joe, W4TV


On 11/24/2015 3:34 PM, Fred Townsend wrote:

> Joe check your schematic and you will see there is both a polyfuse and a
> diode in series with the K3 front panel. The 100w PA pulls off its current
> ahead of the fuse and diode so using the front panel is not indicative of
> the voltage of the current going to power amp. Hang a voltmeter on the APP
> if you want accuracy. Incidentally the polyfuse will permanently change
> cold value after interrupting for the first time so there is another
> variable.
> 73
> Fred, AE6QL
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Joe
> Subich, W4TV
> Sent: Tuesday, November 24, 2015 9:31 AM
> To: Robert Nobis; Elecraft
> Subject: Re: [Elecraft] K3 Voltmeter calibration ...
>
>
>> You could easily drop 0.2 volts in the cable depending how long it
>> isand the gauge of the wire.
>
> Not in six feet of #10 wire at 1.5A.  Even if it were #12 the voltage drop
> should be less than 0.03V (1.62 Ohms/1000 feet for #12).
>
> 73,
>
>      ... Joe, W4TV
>
>
> On 11/24/2015 10:39 AM, Robert Nobis wrote:
>> Joe,
>>
>> How long is your power cable from the RS-35A to your K3, and what gauge
> wire is used?  You could easily drop 0.2 volts in the cable depending how
> long it is and the gauge of the wire.
>>
>> 73,
>>
>>
>> Bob Nobis - N7RJN
>> [hidden email]
>>
>>
>>> On Nov 24, 2015, at 08:06, Joe Subich, W4TV <[hidden email]> wrote:
>>>
>>>
>>> OK, I'm sure I am overlooking something simple but I can not find (or
>>> remember) how to calibrate the voltage display in the K3.
>>>
>>> I had to repair one of my Astron RS-35A power supplies for the first
>>> time in 30 years (one of the diodes shorted) and when I put it back
>>> on line I decided to double check the K3 Volts display against the
>>> actual output of the supply.  The K3 is reading about 0.2V less than
>>> the supply voltage.
>>>
>>> I've been over both the K3 Owner's Manual and the K3 Assembly
>>> Instructions but can't find any reference to calibrating the voltage
>>> display.
>>>
>>> 73,
>>>
>>>     ... Joe, W4TV
>>>
>>> ______________________________________________________________
>>> 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]
>>>
>>
>>
> ______________________________________________________________
> 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]
>
>
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Re: K3 Voltmeter calibration ...

Edward R Cole
In reply to this post by Joe Subich, W4TV-4
Just checked my K3/10 and it displays 13.7 with 13.73v measured where
the power cable is attached to my power distribution.  Negligible
voltage drop in Elecraft supplied power cord when in Rx which displays 1.01a.

73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
Dubus Mag business:
     [hidden email]

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Re: K3 Voltmeter calibration ...

Joe Subich, W4TV-4
In reply to this post by Brian Broggie-2

I've already set ADC REF as documented in the manual.  The Voltage is
still off.  There should be a procedure to set the voltage as there was
when I assembled this K3 (s/n 1450) several years ago.  Unfortunately,
I can no longer find it in the current Owner's Manual or Assembly
Manual.

73,

   ... Joe, W4TV


On 11/24/2015 4:01 PM, Brian & Cyndi wrote:

> Joe, if you just want to make the K3's voltmeter match your "known good"
> reference meter, you need to adjust the "ADC REF" value.
>
> Go into the CONFIG menu, set Tech mode "On", then go to the "ADC REF"
> setting.  Note what it is before changing anything, in case this
> adjustment affects anything else adversely.  Adjust the ADC REF value to
> cause the voltmeter display to read the value you want. You will need to
> go in and out of the menu display to see the results (kinda clumsy).
>
> Again, this adjustment may affect other measurements, so an accurate K3
> voltmeter may not be that important after all.
>
> 73,
> Brian, W6FVI
>
> On 11/24/2015 9:32 AM, Joe Subich, W4TV wrote:
>>
>> It matters not if there is a series diode.  The Voltmeter should
>> be calibrated to the input power.  I remember that being the case
>> when I assembled my first K3.
>>
>> 73,
>>
>>    ... Joe, W4TV
>>
>>
>> On 11/24/2015 11:02 AM, Michael Blake wrote:
>>> Joe, is there not at least one diode junction or solid state switch
>>> in series with the input power inside the K3?
>>>
>>> Michael Blake - K9JRI
>>>
>>>
>>>
>>>
>>>> On Nov 24, 2015, at 10:06 AM, Joe Subich, W4TV <[hidden email]>
>>>> wrote:
>>>>
>>>>
>>>> OK, I'm sure I am overlooking something simple but I can not find
>>>> (or remember) how to calibrate the voltage display in the K3.
>>>>
>>>> I had to repair one of my Astron RS-35A power supplies for the first
>>>> time in 30 years (one of the diodes shorted) and when I put it back on
>>>> line I decided to double check the K3 Volts display against the actual
>>>> output of the supply.  The K3 is reading about 0.2V less than the
>>>> supply voltage.
>>>>
>>>> I've been over both the K3 Owner's Manual and the K3 Assembly
>>>> Instructions but can't find any reference to calibrating the voltage
>>>> display.
>>>>
>>>> 73,
>>>>
>>>>    ... Joe, W4TV
>>>>
>>>> ______________________________________________________________
>>>> 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]
>>>
>>>
>> ______________________________________________________________
>> 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]
>>
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>
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Re: K3 Voltmeter calibration ...

Robert Nobis - N7RJN
In reply to this post by Joe Subich, W4TV-4
A variation of 0.2 volts at 13.6V is less than 1.5%. I wonder how accurate the voltage measuring circuitry is in the K3?

73,

Bob


Bob Nobis - N7RJN
[hidden email]


> On Nov 24, 2015, at 15:39, Ron D'Eau Claire <[hidden email]> wrote:
>
> Joe, as a point of reference, I have a K3 with the bottom off on the bench
> so I checked the voltage at the terminals of the APP connector on the RF
> board with two DMMs. One DMM says 13.63 and the other says 13.66. The FP
> display says 13.4.
>
> It sure looks like they aren't compensating for the 0.2VDC drop across the
> reverse protection diode.
>
> 73, Ron AC7AC
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Joe
> Subich, W4TV
> Sent: Tuesday, November 24, 2015 9:31 AM
> To: Robert Nobis; Elecraft
> Subject: Re: [Elecraft] K3 Voltmeter calibration ...
>
>
>> You could easily drop 0.2 volts in the cable depending how long it
>> isand the gauge of the wire.
>
> Not in six feet of #10 wire at 1.5A.  Even if it were #12 the voltage drop
> should be less than 0.03V (1.62 Ohms/1000 feet for #12).
>
> 73,
>
>    ... Joe, W4TV
>
>
> On 11/24/2015 10:39 AM, Robert Nobis wrote:
>> Joe,
>>
>> How long is your power cable from the RS-35A to your K3, and what gauge
> wire is used?  You could easily drop 0.2 volts in the cable depending how
> long it is and the gauge of the wire.
>>
>> 73,
>>
>>
>> Bob Nobis - N7RJN
>> [hidden email]
>>
>>
>>> On Nov 24, 2015, at 08:06, Joe Subich, W4TV <[hidden email]> wrote:
>>>
>>>
>>> OK, I'm sure I am overlooking something simple but I can not find (or
>>> remember) how to calibrate the voltage display in the K3.
>>>
>>> I had to repair one of my Astron RS-35A power supplies for the first
>>> time in 30 years (one of the diodes shorted) and when I put it back
>>> on line I decided to double check the K3 Volts display against the
>>> actual output of the supply.  The K3 is reading about 0.2V less than
>>> the supply voltage.
>>>
>>> I've been over both the K3 Owner's Manual and the K3 Assembly
>>> Instructions but can't find any reference to calibrating the voltage
>>> display.
>>>
>>> 73,
>>>
>>>   ... Joe, W4TV
>>>
>>> ______________________________________________________________
>>> 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]
>>>
>>
>>
> ______________________________________________________________
> 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]
>
> ______________________________________________________________
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> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Message delivered to [hidden email]
>

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Re: K3 Voltmeter calibration ...

Brian Broggie-2
In reply to this post by Joe Subich, W4TV-4
And the info below is what I found in Fred Cady's book on the K3. There
is no other "calibration" for voltage in that book.

Until Don Wilhelm or Wayne Burdick chimes in,  I suspect there may not
be any other adjustment available.

73,
Brian, W6FVI

On 11/24/2015 1:49 PM, Joe Subich, W4TV wrote:

>
> I've already set ADC REF as documented in the manual.  The Voltage is
> still off.  There should be a procedure to set the voltage as there was
> when I assembled this K3 (s/n 1450) several years ago. Unfortunately,
> I can no longer find it in the current Owner's Manual or Assembly
> Manual.
>
> 73,
>
>   ... Joe, W4TV
>
>
> On 11/24/2015 4:01 PM, Brian & Cyndi wrote:
>> Joe, if you just want to make the K3's voltmeter match your "known good"
>> reference meter, you need to adjust the "ADC REF" value.
>>
>> Go into the CONFIG menu, set Tech mode "On", then go to the "ADC REF"
>> setting.  Note what it is before changing anything, in case this
>> adjustment affects anything else adversely.  Adjust the ADC REF value to
>> cause the voltmeter display to read the value you want. You will need to
>> go in and out of the menu display to see the results (kinda clumsy).
>>
>> Again, this adjustment may affect other measurements, so an accurate K3
>> voltmeter may not be that important after all.
>>
>> 73,
>> Brian, W6FVI
>>
>> On 11/24/2015 9:32 AM, Joe Subich, W4TV wrote:
>>>
>>> It matters not if there is a series diode.  The Voltmeter should
>>> be calibrated to the input power.  I remember that being the case
>>> when I assembled my first K3.
>>>
>>> 73,
>>>
>>>    ... Joe, W4TV
>>>
>>>
>>> On 11/24/2015 11:02 AM, Michael Blake wrote:
>>>> Joe, is there not at least one diode junction or solid state switch
>>>> in series with the input power inside the K3?
>>>>
>>>> Michael Blake - K9JRI
>>>>
>>>>
>>>>
>>>>
>>>>> On Nov 24, 2015, at 10:06 AM, Joe Subich, W4TV <[hidden email]>
>>>>> wrote:
>>>>>
>>>>>
>>>>> OK, I'm sure I am overlooking something simple but I can not find
>>>>> (or remember) how to calibrate the voltage display in the K3.
>>>>>
>>>>> I had to repair one of my Astron RS-35A power supplies for the first
>>>>> time in 30 years (one of the diodes shorted) and when I put it
>>>>> back on
>>>>> line I decided to double check the K3 Volts display against the
>>>>> actual
>>>>> output of the supply.  The K3 is reading about 0.2V less than the
>>>>> supply voltage.
>>>>>
>>>>> I've been over both the K3 Owner's Manual and the K3 Assembly
>>>>> Instructions but can't find any reference to calibrating the voltage
>>>>> display.
>>>>>
>>>>> 73,
>>>>>
>>>>>    ... Joe, W4TV
>>>>>
>>>>> ______________________________________________________________
>>>>> 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]
>>>>
>>>>
>>> ______________________________________________________________
>>> 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]
>>>
>>
>> ______________________________________________________________
>> 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]
>>
> ______________________________________________________________
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> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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Re: K3 Voltmeter calibration ...

markmusick
I sent Joe K3 manual REV D6 from early in 2010.
On page 53 of that manual it has the following description for ADC REF and
how to calibrate it.

ADC REF

Allows calibration of the voltage reference used by the K3 to measure and
display
certain values, such as the rig's supply voltage. (Optional.) First,
disconnect
anything attached to the ACC jack. Next, locate the ADC REF menu entry. It
will
initially show 5.00 volts as the reference voltage. Using a DMM set to DC
volts,
measure the actual voltage at pin 2 of the ACC jack. This must be done while
the
ADC REF parameter is being displayed. (Note: The (-) probe of the DMM
should go to the K3's chassis ground, e.g. at the GROUND lug.) Finally, use
VFO
A to set the ADC REF menu parameter to what you measured at pin 2.

So you need to set ADC REF to the voltage on pin 2 of the ACC jack. NOT what
is at the APP connection on the RF board.

73,

Mark Musick, WB9CIF

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Brian
& Cyndi
Sent: Tuesday, November 24, 2015 11:19 PM
To: [hidden email]
Subject: Re: [Elecraft] K3 Voltmeter calibration ...

And the info below is what I found in Fred Cady's book on the K3. There is
no other "calibration" for voltage in that book.

Until Don Wilhelm or Wayne Burdick chimes in,  I suspect there may not be
any other adjustment available.

73,
Brian, W6FVI

On 11/24/2015 1:49 PM, Joe Subich, W4TV wrote:

>
> I've already set ADC REF as documented in the manual.  The Voltage is
> still off.  There should be a procedure to set the voltage as there
> was when I assembled this K3 (s/n 1450) several years ago.
> Unfortunately, I can no longer find it in the current Owner's Manual
> or Assembly Manual.
>
> 73,
>
>   ... Joe, W4TV
>
>
> On 11/24/2015 4:01 PM, Brian & Cyndi wrote:
>> Joe, if you just want to make the K3's voltmeter match your "known good"
>> reference meter, you need to adjust the "ADC REF" value.
>>
>> Go into the CONFIG menu, set Tech mode "On", then go to the "ADC REF"
>> setting.  Note what it is before changing anything, in case this
>> adjustment affects anything else adversely.  Adjust the ADC REF value
>> to cause the voltmeter display to read the value you want. You will
>> need to go in and out of the menu display to see the results (kinda
clumsy).

>>
>> Again, this adjustment may affect other measurements, so an accurate
>> K3 voltmeter may not be that important after all.
>>
>> 73,
>> Brian, W6FVI
>>
>> On 11/24/2015 9:32 AM, Joe Subich, W4TV wrote:
>>>
>>> It matters not if there is a series diode.  The Voltmeter should be
>>> calibrated to the input power.  I remember that being the case when
>>> I assembled my first K3.
>>>
>>> 73,
>>>
>>>    ... Joe, W4TV
>>>
>>>
>>> On 11/24/2015 11:02 AM, Michael Blake wrote:
>>>> Joe, is there not at least one diode junction or solid state switch
>>>> in series with the input power inside the K3?
>>>>
>>>> Michael Blake - K9JRI
>>>>
>>>>
>>>>
>>>>
>>>>> On Nov 24, 2015, at 10:06 AM, Joe Subich, W4TV <[hidden email]>
>>>>> wrote:
>>>>>
>>>>>
>>>>> OK, I'm sure I am overlooking something simple but I can not find
>>>>> (or remember) how to calibrate the voltage display in the K3.
>>>>>
>>>>> I had to repair one of my Astron RS-35A power supplies for the
>>>>> first time in 30 years (one of the diodes shorted) and when I put
>>>>> it back on line I decided to double check the K3 Volts display
>>>>> against the actual output of the supply.  The K3 is reading about
>>>>> 0.2V less than the supply voltage.
>>>>>
>>>>> I've been over both the K3 Owner's Manual and the K3 Assembly
>>>>> Instructions but can't find any reference to calibrating the
>>>>> voltage display.
>>>>>
>>>>> 73,
>>>>>
>>>>>    ... Joe, W4TV
>>>>>
>>>>> ______________________________________________________________
>>>>> 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]
>>>>
>>>>
>>> ______________________________________________________________
>>> 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]
>>>
>>
>> ______________________________________________________________
>> 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]
>>
> ______________________________________________________________
> 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]
>

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Re: K3 Voltmeter calibration ...

Joe Subich, W4TV-4

As I responded to to Mark off list, I know the REF ADC calibration and
had already performed it *before* asking for assistance here.  The
voltage display was off by more than 0.5 V prior to performing REF ADC.
The remaining the error is still unacceptably high at more than 0.2
Volts when a simple DVM has significantly greater accuracy.

I *still* seem to recall a calibration procedure for voltage similar to
that for FP, PA, etc. during the initial assembly and test of this K3.
It seems inconceivable that such a calibration process would not be
present since the "12V" sense point follows at least D6 if not D6, Q2,
RFC40 and R36 which in total would introduce a substantial fraction of
a volt offset from the voltage at the APP and provided to the KPA3.

73,

   ... Joe, W4TV


On 11/24/2015 6:32 PM, Mark E. Musick wrote:

> I sent Joe K3 manual REV D6 from early in 2010.
> On page 53 of that manual it has the following description for ADC REF and
> how to calibrate it.
>
> ADC REF
>
> Allows calibration of the voltage reference used by the K3 to measure and
> display
> certain values, such as the rig's supply voltage. (Optional.) First,
> disconnect
> anything attached to the ACC jack. Next, locate the ADC REF menu entry. It
> will
> initially show 5.00 volts as the reference voltage. Using a DMM set to DC
> volts,
> measure the actual voltage at pin 2 of the ACC jack. This must be done while
> the
> ADC REF parameter is being displayed. (Note: The (-) probe of the DMM
> should go to the K3's chassis ground, e.g. at the GROUND lug.) Finally, use
> VFO
> A to set the ADC REF menu parameter to what you measured at pin 2.
>
> So you need to set ADC REF to the voltage on pin 2 of the ACC jack. NOT what
> is at the APP connection on the RF board.
>
> 73,
>
> Mark Musick, WB9CIF
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Brian
> & Cyndi
> Sent: Tuesday, November 24, 2015 11:19 PM
> To: [hidden email]
> Subject: Re: [Elecraft] K3 Voltmeter calibration ...
>
> And the info below is what I found in Fred Cady's book on the K3. There is
> no other "calibration" for voltage in that book.
>
> Until Don Wilhelm or Wayne Burdick chimes in,  I suspect there may not be
> any other adjustment available.
>
> 73,
> Brian, W6FVI
>
> On 11/24/2015 1:49 PM, Joe Subich, W4TV wrote:
>>
>> I've already set ADC REF as documented in the manual.  The Voltage is
>> still off.  There should be a procedure to set the voltage as there
>> was when I assembled this K3 (s/n 1450) several years ago.
>> Unfortunately, I can no longer find it in the current Owner's Manual
>> or Assembly Manual.
>>
>> 73,
>>
>>    ... Joe, W4TV
>>
>>
>> On 11/24/2015 4:01 PM, Brian & Cyndi wrote:
>>> Joe, if you just want to make the K3's voltmeter match your "known good"
>>> reference meter, you need to adjust the "ADC REF" value.
>>>
>>> Go into the CONFIG menu, set Tech mode "On", then go to the "ADC REF"
>>> setting.  Note what it is before changing anything, in case this
>>> adjustment affects anything else adversely.  Adjust the ADC REF value
>>> to cause the voltmeter display to read the value you want. You will
>>> need to go in and out of the menu display to see the results (kinda
> clumsy).
>>>
>>> Again, this adjustment may affect other measurements, so an accurate
>>> K3 voltmeter may not be that important after all.
>>>
>>> 73,
>>> Brian, W6FVI
>>>
>>> On 11/24/2015 9:32 AM, Joe Subich, W4TV wrote:
>>>>
>>>> It matters not if there is a series diode.  The Voltmeter should be
>>>> calibrated to the input power.  I remember that being the case when
>>>> I assembled my first K3.
>>>>
>>>> 73,
>>>>
>>>>     ... Joe, W4TV
>>>>
>>>>
>>>> On 11/24/2015 11:02 AM, Michael Blake wrote:
>>>>> Joe, is there not at least one diode junction or solid state switch
>>>>> in series with the input power inside the K3?
>>>>>
>>>>> Michael Blake - K9JRI
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> On Nov 24, 2015, at 10:06 AM, Joe Subich, W4TV <[hidden email]>
>>>>>> wrote:
>>>>>>
>>>>>>
>>>>>> OK, I'm sure I am overlooking something simple but I can not find
>>>>>> (or remember) how to calibrate the voltage display in the K3.
>>>>>>
>>>>>> I had to repair one of my Astron RS-35A power supplies for the
>>>>>> first time in 30 years (one of the diodes shorted) and when I put
>>>>>> it back on line I decided to double check the K3 Volts display
>>>>>> against the actual output of the supply.  The K3 is reading about
>>>>>> 0.2V less than the supply voltage.
>>>>>>
>>>>>> I've been over both the K3 Owner's Manual and the K3 Assembly
>>>>>> Instructions but can't find any reference to calibrating the
>>>>>> voltage display.
>>>>>>
>>>>>> 73,
>>>>>>
>>>>>>     ... Joe, W4TV
>>>>>>
>>>>>> ______________________________________________________________
>>>>>> 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]
>>>>>
>>>>>
>>>> ______________________________________________________________
>>>> 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]
>>>>
>>>
>>> ______________________________________________________________
>>> 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]
>>>
>> ______________________________________________________________
>> 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]
>>
>
> ______________________________________________________________
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>
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> Please help support this email list: http://www.qsl.net/donate.html Message
> delivered to [hidden email]
>
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Re: K3 Voltmeter calibration ...

Joe Subich, W4TV-4

On 11/24/2015 8:17 PM, Walter Underwood wrote:
> The measured voltage is what the rig is really seeing, after the
> protection.

That *is not the case* I've checked the voltage on the KPA3 and, again,
the Voltage display is approximately 0.2 Volts *lower* than measured at
"12PA" - the output of CB1.

Again, *HOW DOES ONE CALIBRATE THE VOLTAGE DISPLAY?*

CONFIG: ADC REF matches the voltage measured at pin 2 of the ACC jack
with nothing connected to the +12V Out.  However, the Voltage display
does not match the voltage at either the APP or +12PA.  That the
"meter" is not accurate at *either of the two* most important points
- the two points that have the greatest impact on performance - is not
acceptable.

*HOW DOES ONE CALIBRATE THE VOLTAGE DISPLAY?*

73,

   ... Joe, W4TV


On 11/24/2015 8:17 PM, Walter Underwood wrote:

> The measured voltage is what the rig is really seeing, after the protection. If you don’t want that, you need to put your own voltmeter outside the rig.
>
> A 0.2V difference isn’t calibration, this is you disagreeing with an Elecraft design decision.
>
> wunder
> K6WRU
> Walter Underwood
> CM87wj
> http://observer.wunderwood.org/ (my blog)
>
>> On Nov 24, 2015, at 4:55 PM, Joe Subich, W4TV <[hidden email]> wrote:
>>
>>
>> As I responded to to Mark off list, I know the REF ADC calibration and
>> had already performed it *before* asking for assistance here.  The
>> voltage display was off by more than 0.5 V prior to performing REF ADC.
>> The remaining the error is still unacceptably high at more than 0.2 Volts when a simple DVM has significantly greater accuracy.
>>
>> I *still* seem to recall a calibration procedure for voltage similar to
>> that for FP, PA, etc. during the initial assembly and test of this K3.
>> It seems inconceivable that such a calibration process would not be
>> present since the "12V" sense point follows at least D6 if not D6, Q2,
>> RFC40 and R36 which in total would introduce a substantial fraction of
>> a volt offset from the voltage at the APP and provided to the KPA3.
>>
>> 73,
>>
>>   ... Joe, W4TV
>>
>>
>> On 11/24/2015 6:32 PM, Mark E. Musick wrote:
>>> I sent Joe K3 manual REV D6 from early in 2010.
>>> On page 53 of that manual it has the following description for ADC REF and
>>> how to calibrate it.
>>>
>>> ADC REF
>>>
>>> Allows calibration of the voltage reference used by the K3 to measure and
>>> display
>>> certain values, such as the rig's supply voltage. (Optional.) First,
>>> disconnect
>>> anything attached to the ACC jack. Next, locate the ADC REF menu entry. It
>>> will
>>> initially show 5.00 volts as the reference voltage. Using a DMM set to DC
>>> volts,
>>> measure the actual voltage at pin 2 of the ACC jack. This must be done while
>>> the
>>> ADC REF parameter is being displayed. (Note: The (-) probe of the DMM
>>> should go to the K3's chassis ground, e.g. at the GROUND lug.) Finally, use
>>> VFO
>>> A to set the ADC REF menu parameter to what you measured at pin 2.
>>>
>>> So you need to set ADC REF to the voltage on pin 2 of the ACC jack. NOT what
>>> is at the APP connection on the RF board.
>>>
>>> 73,
>>>
>>> Mark Musick, WB9CIF
>>>
>>> -----Original Message-----
>>> From: Elecraft [mailto:[hidden email]] On Behalf Of Brian
>>> & Cyndi
>>> Sent: Tuesday, November 24, 2015 11:19 PM
>>> To: [hidden email]
>>> Subject: Re: [Elecraft] K3 Voltmeter calibration ...
>>>
>>> And the info below is what I found in Fred Cady's book on the K3. There is
>>> no other "calibration" for voltage in that book.
>>>
>>> Until Don Wilhelm or Wayne Burdick chimes in,  I suspect there may not be
>>> any other adjustment available.
>>>
>>> 73,
>>> Brian, W6FVI
>>>
>>> On 11/24/2015 1:49 PM, Joe Subich, W4TV wrote:
>>>>
>>>> I've already set ADC REF as documented in the manual.  The Voltage is
>>>> still off.  There should be a procedure to set the voltage as there
>>>> was when I assembled this K3 (s/n 1450) several years ago.
>>>> Unfortunately, I can no longer find it in the current Owner's Manual
>>>> or Assembly Manual.
>>>>
>>>> 73,
>>>>
>>>>    ... Joe, W4TV
>>>>
>>>>
>>>> On 11/24/2015 4:01 PM, Brian & Cyndi wrote:
>>>>> Joe, if you just want to make the K3's voltmeter match your "known good"
>>>>> reference meter, you need to adjust the "ADC REF" value.
>>>>>
>>>>> Go into the CONFIG menu, set Tech mode "On", then go to the "ADC REF"
>>>>> setting.  Note what it is before changing anything, in case this
>>>>> adjustment affects anything else adversely.  Adjust the ADC REF value
>>>>> to cause the voltmeter display to read the value you want. You will
>>>>> need to go in and out of the menu display to see the results (kinda
>>> clumsy).
>>>>>
>>>>> Again, this adjustment may affect other measurements, so an accurate
>>>>> K3 voltmeter may not be that important after all.
>>>>>
>>>>> 73,
>>>>> Brian, W6FVI
>>>>>
>>>>> On 11/24/2015 9:32 AM, Joe Subich, W4TV wrote:
>>>>>>
>>>>>> It matters not if there is a series diode.  The Voltmeter should be
>>>>>> calibrated to the input power.  I remember that being the case when
>>>>>> I assembled my first K3.
>>>>>>
>>>>>> 73,
>>>>>>
>>>>>>     ... Joe, W4TV
>>>>>>
>>>>>>
>>>>>> On 11/24/2015 11:02 AM, Michael Blake wrote:
>>>>>>> Joe, is there not at least one diode junction or solid state switch
>>>>>>> in series with the input power inside the K3?
>>>>>>>
>>>>>>> Michael Blake - K9JRI
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> On Nov 24, 2015, at 10:06 AM, Joe Subich, W4TV <[hidden email]>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> OK, I'm sure I am overlooking something simple but I can not find
>>>>>>>> (or remember) how to calibrate the voltage display in the K3.
>>>>>>>>
>>>>>>>> I had to repair one of my Astron RS-35A power supplies for the
>>>>>>>> first time in 30 years (one of the diodes shorted) and when I put
>>>>>>>> it back on line I decided to double check the K3 Volts display
>>>>>>>> against the actual output of the supply.  The K3 is reading about
>>>>>>>> 0.2V less than the supply voltage.
>>>>>>>>
>>>>>>>> I've been over both the K3 Owner's Manual and the K3 Assembly
>>>>>>>> Instructions but can't find any reference to calibrating the
>>>>>>>> voltage display.
>>>>>>>>
>>>>>>>> 73,
>>>>>>>>
>>>>>>>>     ... Joe, W4TV
>>>>>>>>
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