KPA3(A) Extender Board for adjusting the output devices bias...?
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Has anyone investigated getting/creating an extender board to enable adjusting the output device bias?
If I had such a board, then what would I be looking at to properly adjust the bias? Or, what is the idling requirement for both KPA3(A) amplifiers? Or again, what are the alignment adjustments for these amplifiers? Chuck Hawley [hidden email] Amateur Radio, KE9UW aka Jack, BMW Motorcycles ______________________________________________________________ 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
Chuck, KE9UW
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I suspect that Elecraft would rather we didn’t have such a control.
Can you imagine the tech support nightmare if we started turning all the slotted screws “Tight to the right”! Sent from my iPhone ...nr4c. bill > On Mar 6, 2019, at 6:11 PM, hawley, charles j jr <[hidden email]> wrote: > > Has anyone investigated getting/creating an extender board to enable adjusting the output device bias? > If I had such a board, then what would I be looking at to properly adjust the bias? Or, what is the idling requirement for both KPA3(A) amplifiers? > Or again, what are the alignment adjustments for these amplifiers? > > Chuck Hawley > [hidden email] > > Amateur Radio, KE9UW > aka Jack, BMW Motorcycles > ______________________________________________________________ > 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 > Has anyone investigated getting/creating an extender board to enable adjusting the output device bias? > If I had such a board, then what would I be looking at to properly adjust the bias? Or, what is the idling requirement for both KPA3(A) amplifiers? > Or again, what are the alignment adjustments for these amplifiers? > > Chuck Hawley > [hidden email] > > Amateur Radio, KE9UW > aka Jack, BMW Motorcycles > ______________________________________________________________ > 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 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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Licensed amateur radio operators should either know what they are doing or know not to do it. One could only hope...but restricting technical learning is not the road to take.
Chuck KE9UW Sent from my iPhone, cjack > On Mar 6, 2019, at 6:43 PM, Nr4c <[hidden email]> wrote: > > I suspect that Elecraft would rather we didn’t have such a control. > > Can you imagine the tech support nightmare if we started turning all the slotted screws “Tight to the right”! > > > Sent from my iPhone > ...nr4c. bill > > >> On Mar 6, 2019, at 6:11 PM, hawley, charles j jr <[hidden email]> wrote: >> >> Has anyone investigated getting/creating an extender board to enable adjusting the output device bias? >> If I had such a board, then what would I be looking at to properly adjust the bias? Or, what is the idling requirement for both KPA3(A) amplifiers? >> Or again, what are the alignment adjustments for these amplifiers? >> >> Chuck Hawley >> [hidden email] >> >> Amateur Radio, KE9UW >> aka Jack, BMW Motorcycles >> ______________________________________________________________ >> 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 >> Has anyone investigated getting/creating an extender board to enable adjusting the output device bias? >> If I had such a board, then what would I be looking at to properly adjust the bias? Or, what is the idling requirement for both KPA3(A) amplifiers? >> Or again, what are the alignment adjustments for these amplifiers? >> >> Chuck Hawley >> [hidden email] >> >> Amateur Radio, KE9UW >> aka Jack, BMW Motorcycles >> ______________________________________________________________ >> 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 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
Chuck, KE9UW
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Re: KPA3(A) Extender Board for adjusting the output devices bias...?
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In reply to this post by ke9uw
On 3/6/2019 3:11 PM, hawley, charles j jr wrote:
> Or again, what are the alignment adjustments for these amplifiers? There are none. Everything is pre-tuned and tested at the factory. 73, Jim K9YC ______________________________________________________________ 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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Ok. What are they at the factory?
Chuck Jack KE9UW Sent from my iPhone, cjack > On Mar 6, 2019, at 7:02 PM, Jim Brown <[hidden email]> wrote: > >> On 3/6/2019 3:11 PM, hawley, charles j jr wrote: >> Or again, what are the alignment adjustments for these amplifiers? > > There are none. Everything is pre-tuned and tested at the factory. > > 73, Jim K9YC > > ______________________________________________________________ > 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 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
Chuck, KE9UW
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Greetings All,
Having just acquired K3 #00626 to tidy up and use portable but mainly as a transverter driver, I found that the KPA3 Rev B gave no output. Visual inspection showed nothing amiss. To start checking it was impossible in the rig except proving that it drew 14 Amps above 12 W for any power demanded. Took me a while to figure out that as all the odd and even pin pairs are linked, I could use a couple of untwisted pair 20 pin IDC cables with female connectors and double 8mm pin length double male header strips to connect the KPA upside down, outside the back of the rig. 100mm long ribbon cables are sufficient. This soon revealed some hot smelling electronics so signal tracing at this stage proved to be impossible. By trial and error removing suspect components for out of circuit testing, D10 pin diode was found to be open circuit. The KPA3 is currently with the UK dealers for further testing and repair since the D10 MA4P leaded diode appears to be absent from UK stockists and I don’t know if anything else is damaged. Sorry Charles, I also have not been able to find any referenced information on setting the bias, despite looking for it in case I had to change the power transistors. 73, Ted G7BQM > On 7 Mar 2019, at 02:47, hawley, charles j jr <[hidden email]> wrote: > > Ok. What are they at the factory? > > Chuck Jack > KE9UW > > Sent from my iPhone, cjack > >> On Mar 6, 2019, at 7:02 PM, Jim Brown <[hidden email]> wrote: >> >>> On 3/6/2019 3:11 PM, hawley, charles j jr wrote: >>> Or again, what are the alignment adjustments for these amplifiers? >> >> There are none. Everything is pre-tuned and tested at the factory. >> >> 73, Jim K9YC >> >> ______________________________________________________________ >> 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 > 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 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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