K2 Deaf
Locked
 
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Initial receiver testing on 40 Meters (pg 67) can barely hear XG2/XG3 @
50uV. I've injected the 50uV from the XG2 directly to the input of the rcv. mixer Z6 @ R73, no change. VFO Input to the receive mixer looks good on a scope, no IF signal to be found at pin 1 of J12. Q22 voltages nominal. I've eyeballed all solder connections and Caps and Resistors and confirmed values. We have confirmed the injection and testing procedure on a known good K2, lots of IF signal at J12 pin 1. Looks like Z6 is the problem? Any other ideas or thoughts? 73, KC2VMP Rob Gault ______________________________________________________________ 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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Rob,
Look at the mixer carefully, especially the silkscreen outline on the board. If it is installed backwards, the results will be much as you describe. If the mixer is installed correctly, then you may have to build up the oscillator shown in Appendix A (or use a signal generator with much more output than the XG1 or XG2 can provide) and do the Receiver Signal Tracing steps shown in the manual Appendix A. 73, Don W3FPR On 10/29/2013 6:30 PM, Rob Gault wrote: > Initial receiver testing on 40 Meters (pg 67) can barely hear XG2/XG3 @ > 50uV. I've injected the 50uV from the XG2 directly to the input of the > rcv. mixer Z6 @ R73, no change. VFO Input to the receive mixer looks good > on a scope, no IF signal to be found at pin 1 of J12. Q22 voltages > nominal. > > I've eyeballed all solder connections and Caps and Resistors and confirmed > values. > > We have confirmed the injection and testing procedure on a known good K2, > lots of IF signal at J12 pin 1. > > Looks like Z6 is the problem? Any other ideas or thoughts? > > ______________________________________________________________ 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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Don,
Thank you for your guidance! It turned I had a short to ground at R88 and 2.7K resistor at R89 from the UN-PCB supplement. While I know it is common to place parts incorrectly, I was glad not to have made the mistake of simply not soldering something. Again, thank you for the quick and very helpful "support", you are a tremendous asset to the community. 73, kc2vmp Rob Gault On Oct 29, 2013, at 6:45 PM, Don Wilhelm <[hidden email]> wrote: > Rob, > > Look at the mixer carefully, especially the silkscreen outline on the board. > If it is installed backwards, the results will be much as you describe. > > If the mixer is installed correctly, then you may have to build up the oscillator shown in Appendix A (or use a signal generator with much more output than the XG1 or XG2 can provide) and do the Receiver Signal Tracing steps shown in the manual Appendix A. > > 73, > Don W3FPR > > On 10/29/2013 6:30 PM, Rob Gault wrote: >> Initial receiver testing on 40 Meters (pg 67) can barely hear XG2/XG3 @ >> 50uV. I've injected the 50uV from the XG2 directly to the input of the >> rcv. mixer Z6 @ R73, no change. VFO Input to the receive mixer looks good >> on a scope, no IF signal to be found at pin 1 of J12. Q22 voltages >> nominal. >> >> I've eyeballed all solder connections and Caps and Resistors and confirmed >> values. >> >> We have confirmed the injection and testing procedure on a known good K2, >> lots of IF signal at J12 pin 1. >> >> Looks like Z6 is the problem? Any other ideas or thoughts? >> >> > ______________________________________________________________ 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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Good to hear you have it solved Rob.
Glad I could help guide your troubleshooting steps. 73, Don W3FPR On 10/31/2013 7:48 AM, kc2vmp wrote: > Don, > > Thank you for your guidance! It turned I had a short to ground at R88 and 2.7K resistor at R89 from the UN-PCB supplement. While I know it is common to place parts incorrectly, I was glad not to have made the mistake of simply not soldering something. > > Again, thank you for the quick and very helpful "support", you are a tremendous asset to the community. > ______________________________________________________________ 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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