[Elecraft] K3 Voltmeter calibration ...

[Robert Nobis]

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
n7rjn at nobis.net


> On Nov 24, 2015, at 15:39, Ron D'Eau Claire <ron at cobi.biz> 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:elecraft-bounces at mailman.qth.net] 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
>> n7rjn at nobis.net
>> 
>> 
>>> On Nov 24, 2015, at 08:06, Joe Subich, W4TV <lists at subich.com> 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:Elecraft at mailman.qth.net
>>> 
>>> This list hosted by: http://www.qsl.net Please help support this 
>>> email list: http://www.qsl.net/donate.html Message delivered to 
>>> n7rjn at nobis.net
>>> 
>> 
>> 
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html Message
> delivered to ron at elecraft.com
> 
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to n7rjn at nobis.net
>