2nd Xtal Filter and Product Detector Output problems

Posted by K5JAZ on May 08, 2009; 4:03am
URL: http://elecraft.85.s1.nabble.com/2nd-Xtal-Filter-and-Product-Detector-Output-problems-tp2843492.html

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
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