Hi gang, It's Merlin, W3ICT; you know, the guy who complains about the filter in the KSB2 all the time. This time, it's actually something different. Recently I had to replace the finals in my K2 (2631). In the process of measuring forward bias, I accidentally lunched the SC1969s with clumsy metering skills. Got the finals put back no problem, but a strange thing has surfaced, and I wonder if anybody has seen it before. Unrelated to the finals, I turned the K2 on and the S meter pegged and the receiver shut down its 1350P IF amp. I measured the AGC voltage. It's way up there at 5.5 volts, regardless of whether the AGC is disabled and regardless of the position of the RF gain control. Sure enough, if I lift the collector on Q12, the receiver comes up to full sensitivity. If I lift d2 (these are all components on the control board, by the way), thus depriving the AGC amp of a signal from the IF, it still makes no difference; the AGC amplifier still makes too much voltage. Any thoughts? Everything else works, by the way. Does U2 just go bad sometimes? By the way, in the matter of filters, I've come up with a simple shielding technique, using tin sheet from hobby shops, that actually improves the ultimate rejection and the shape factor of the seven pole device that's used in the KSB2. I bet somebody out there has experienced this weirdness. I hope Regards, Merlin, W3ICT _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft
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