Jim, If you had the expected output at U12 pin 8, but less than expected at U11 pin 1, then there is a problem between those two points. Look at the schematic in conjunction with these troubleshooting steps to find what lies between the two points - in this case, look in the lower right quadrant of RF Board schematic sheet 2.
Since the signal is going through a crystal filter, move the frequency a little bit to see if the level increases. Concentrate on the 2nd IF filter before proceeding to the Product Detector. 73, Don W3FPR Jim Brown wrote: > I am using the procedures in a Rev C manual, Appendix E, Page 10-11 to > troubleshoot a "dead receiver" problem. All Rework Eliminators are > installed. Signal tracing through the PLL/VCO and Low-Pass Filter, > Bandpass Filter, and T-R Switch produced expected measurements. In the > Mixer, I.F. Amp, and Xtal Filter section, some anomalies were found. > Specifically, the 2nd Crystal Filter Output measured at U11 pin 1 > expects 0.27Vrms but measures only 0.17Vrms (paragraph 9). The Product > Detector Saturated Output measurement expects 0.58Vrms but measures > only 0.08Vrms (paragraph 10). These measurements produced with input > of 0.15Vrms as measured at U12, pin 8 per instructions in paragraph 8. > > I reheated solder joints on all components around these sections with > no change of measurements. Any help appreciated. > > > Regards, > Jim Brown, K5JAZ > ______________________________________________________________ > 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 > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.325 / Virus Database: 270.12.21/2102 - Release Date: 05/07/09 > 05:57:00 > > ______________________________________________________________ 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
