Re: Low output from 2nd crystal filter and SA602 product detector

Posted by n7zf on Feb 02, 2011; 4:06pm
URL: http://elecraft.85.s1.nabble.com/Low-output-from-2nd-crystal-filter-and-SA602-product-detector-tp5979986p5985369.html

I am still trying to find what is causing high current on transmit.

DC voltages on the PA Driver Q6: emitter is only 0.24 volts (on transmit).  Base is 1.0 VDC.

In the PA Bias circuit, the collector of Q13 is 6.6 VDC on transmit, so there is 13 mA of DC current in the collector circuit.  The expected current is 4mA, I think.  There is no current through R60, so it must be going to the finals.  The base voltage on Q7 and Q8 is .63 VDC.

Bob Willis - N7ZF