Brian, DON'T DO THAT! If the K2 is developing any power, it will not do it for long without a 50 ohm dummy load. The PA transistors can go "poof" in a hurry when operated into an open circuit - yes, the small antenna wire is an open circuit.
73, Don W3FPR On 9/19/2010 10:39 PM, Brian Denley wrote: > ?I should add: If I connect a small wire to my K2 antenna and press tune, > it shows a strong signal on any of my receivers at that frequency. So > somethings coming out of the K2. Either the ouput signal is low OR the K2 > RF detector just doesn't measure it correctly for the ALC circuit. > Brian Denley > http://home.comcast.net/~b.denley/index.html > > > ----- Original Message ----- > From: "Brian Denley"<b.den...@comcast.net> > To:<d...@w3fpr.com> > Cc: "Elecraft Reflector"<elecraft@mailman.qth.net> > Sent: Sunday, September 19, 2010 10:26 PM > Subject: Re: [Elecraft] [K2] No Transmit Power > > >> ?I am just about at the end of my rope trying to get this K2 to transmit. >> Nothing is coming out of the transmitter because nothing seems to be going >> into the PA circuit. The receiver circuits all work fine. All RF board >> transistors and diodes check out fine as far as DC is concerned but my RF >> probe does not function and I am unable to find the fault. I suspect the >> T/R switch or whatever circuit generates the RF signal in the first place >> but the trouble shooting help in the manual does not go yery deep on those >> issues. What is my next step? Does Elecraft offer a repair service? I >> have been at this for 4 weeks now with no progress at all. >> Thanks >> Brian Denley >> http://home.comcast.net/~b.denley/index.html >> >> >> ----- Original Message ----- >> From: "Don Wilhelm"<w3...@embarqmail.com> >> To: "Brian Denley"<b.den...@comcast.net> >> Cc: "Elecraft Reflector"<elecraft@mailman.qth.net> >> Sent: Tuesday, September 07, 2010 11:08 PM >> Subject: Re: [Elecraft] [K2] No Transmit Power >> >> >>> On 9/7/2010 10:16 PM, Brian Denley wrote: >>>> Don: >>>> I brought home a DSO5054A (very nice 500 MHz Agilent scope!) and I was >>>> able >>>> to take the better measurements. My measurements were in P-to-P but I >>>> have >>>> divided them by 2.8 for RMS comparison:\ >>>> (all measurments Keydown) >>>> >>>> 1.) VPWR line (pin 2 of U8 on control board): 5.0 volts >>>> this >>>> is >>>> HIGH >>>> >>>> 2.) Xmit Mixer Output (pin 4 of U10): 28 mV >>>> >>>> 3.) Buffer Output (pin 6 of U9): 121 mV >>>> >>>> 4.) Band-Pass Filter Output (W6): 42 mV >>>> >>>> 5.) T-R Switch #1 Output (anode of D1): 41 mV >>>> >>>> 6.) Pre-Driver Output (collector of Q5): 34 mV this >>>> seems >>>> LOW >>>> 7.) Driver Input (base of Q6): 34 mV >>>> 8.) Driver Output (collector of Q6): 179 mV this is >>>> VERY LOW >>>> 9.) PA Inputy (base of Q7): 80 mV >>>> this >>>> seems HIGH >>>> 10.) PA input (base of Q8): 80 mV this >>>> seems HIGH >>>> 11.) RF Detector Input (anode of D9): 143 mV this is VERY >>>> LOW >>>> on my own I also measured: >>>> 12.) base of Q5: 43 mV >>>> 13.) out of C107 43 mV >>>> all of the DC voltages in column 1 on page 17 are normal >> ______________________________________________________________ >> 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 > ______________________________________________________________ > 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 > ______________________________________________________________ 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
