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 <li...@subich.com> 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:elecraft-boun...@mailman.qth.net] On Behalf Of Brian >> & Cyndi >> Sent: Tuesday, November 24, 2015 11:19 PM >> To: elecraft@mailman.qth.net >> 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 <li...@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@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 >>>>>>> k9...@mac.com >>>>>> >>>>>> >>>>> ______________________________________________________________ >>>>> Elecraft mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:Elecraft@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 >>>>> w6...@sbcglobal.net >>>>> >>>> >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:Elecraft@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 >>>> li...@subich.com >>>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Elecraft@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 >>> w6...@sbcglobal.net >>> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@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 markmus...@sbcglobal.net >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@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 li...@subich.com >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@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 wun...@wunderwood.org ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@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 arch...@mail-archive.com
