Hello folks, I think I must be kin to Joe Bftsplk of L'il Abner fame years ago.....I seem to have a black cloud hovering over me as I build and check #5061. I had a problem with Q6 being overtaxed by a 4V bias on the base during keydown which turned out to be a shorted Q10 FET. When I got that fixed I anxiously started to finish the calibration only to find the PLL now won't lock! I had that problem during the build which turned out to be a solder bridge on the thermister board shorting the 4V ref for the PLL comparator. Once I fixed that the cal went smoothly.
I have rechecked all connections on T5 and have reheated all connections on the RF board with no improvement. The oscillators are running (I can hear stations drift by as I put my finger near T5 or other oscillator components or when I tweak L30.) I have scoped all signals in the PLL chain and they are all there except for SCK. I checked that signal on the control board and it is also missing. The signal sits at logic high with no pulses. I would expect that signal to run all the time if I understand the circuit correctly. I removed the control board and reseated U6 MCU with no change in symptoms. Anyone have any suggestions where to go from here? Thanks in advance, Pat Haynes-K4BEH (706) 692-0279 _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
