Gregg, There are no ICs on the KSB2 board that should cause a problem of that nature. When in CW mode, and during transmit, the only components that should be in the signal path electrically are C42, D3, Q3 and C39.
Follow along on the KSB2 schematic - at the bottom, the BFO signal enters at P1 pin 12, goes through C42, then D3 should be conducting because the TXC signal from the KSB2 firmware should be active (+5v) during CW transmit. The TXC signal also causes Q3 to conduct and the BFO signal flows out the emitter of Q1 and through C39 to pin 7 of P1 - from there it goes to the RF Board and on to the transmit mixer. Be certain the TXC signal is correctly present from the firmware chip (Pin 12 of U1). So there is little involved on the KSB2 board for CW transmit. Check to see if you have the proper conditions present for the signal flow described above, and that information should lead you to the source of the problem. Check Q3, D3, and possibly D5. 73, Don W3FPR > -----Original Message----- > > Hello agn fellow Elecrafters, > I still have a problem with my K2, upon cold startup. power > cont. set to 5w. CW mode. when 1st x-mit . bargraph shows almost > no ind. but hi curent alarm, power out is 10+ watts( 40m) es > after a minite or 2 all is backto normal with bar graph showing > 5w es power out is 5w es no alarm. i followed Keith Darwins > suggestion es made some rework eliminators. I narrowed the > problem to when the ssb brd is plugged in. with ssb brd out, all > is fine. I went thru a rebuild of the ssb board es all parts are > in proper places es no cold solder joint or bridges. Problem is > with ssb brd. could my problem be a faulty (intermittent) IC ??? > Any sugestions appreciated. tnx, Gregg WB8LZG > _______________________________________________ > _______________________________________________ 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 Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
