I think I've nailed it down as an interaction between the bottom cover and L33, which mounted on that rubber spacer on the bottom side of the RF board. I can get the same BFO shift effect by barely pushing on L33 with an insulated tool, for example. I took the cover off and measured clearances, and L33 seems to be well below the height of the two spacers. However the cover has a bit of flex to it (maybe made worse by the tilt stand), and pushing on the bottom cover does cause the BFO to shift, although it does not, AFAIK, actually touch L33.
Not clear that there is anything to be done about it. Now that I know, I'll just need to avoid pushing on the case, particularly from the bottom. Will realign filters once more and see if they stabilize. Thanks for the help! ----- Bruce Rosen K1FFX -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-BFO-Drift-Filter-Alignment-tp4236424p5893826.html Sent from the [K2] 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html