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:[email protected]] On Behalf Of Brian & Cyndi Sent: Tuesday, November 24, 2015 11:19 PM To: [email protected] 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 <[email protected]> >>>>> 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:[email protected] >>>>> >>>>> This list hosted by: http://www.qsl.net Please help support this >>>>> email list: http://www.qsl.net/donate.html Message delivered to >>>>> [email protected] >>>> >>>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[email protected] >>> >>> This list hosted by: http://www.qsl.net Please help support this >>> email list: http://www.qsl.net/donate.html Message delivered to >>> [email protected] >>> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> This list hosted by: http://www.qsl.net Please help support this >> email list: http://www.qsl.net/donate.html Message delivered to >> [email protected] >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html Message delivered to > [email protected] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
