Don Wilhelm-4 wrote > The bottom line is that the BFO frequency is 'drifting'. > The most probable cause is a defective solder connection in the BFO area. > Carefully lift L33 and reflow the soldering of the BFO crystals. Reflow > the soldering of C173 and C174, RP6. D37, D38, C169 and Q24. > Make certain when you replace L33 that the leads of the resistor are > well soldered and the leads of L33 are soldered to the resistor leads.
Thanks for the specific and detailed hints, Don (and thanks also to Matt and Bob for helpful e-mails). I decided to defer handling L33 and the two BFO crystals. I went ahead and reflowed the soldering for the other components. This has fixed the immediate problem: the center frequencies moved "up" and was I able to easily align all the filters. Hopefully, this will be a permanent fix and there will be no further significant BFO drift. If I continue to see drift, then I'll go ahead deal with L33 (whose solder joints all looked fine to me yesterday) and reflow the BFO crystals' soldered leads. Thanks again! - Bruce K1FFX ----- Bruce Rosen K1FFX K2/100 6982 KSB2 KAT100-1 -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-K2-filters-continue-to-drift-out-of-alignment-tp7609910p7609932.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
