This is also just about a common interval since assembly for a missed solder connection to show up producing an intermittent or open connection as oxidation builds up on the unsoldered metal surfaces.
Ron AC7AC -----Original Message----- Graham, The fact that the relays did not cycle to reset with the control board removed is not likely an indication of the problem. If I recall, this 'feature' does not work since the KIO chip firmware was reworked to add 60 meters. That is only a guess, but I too tried this step to reset the relays in the near past and found it did not work. You may want to try doing continuity checks through the relay coils from the top of the U1 socket. If all looks well there, the relay may be 'sluggish'. Of course, it may be that there has been a bit of oxidation on the socket or pins of U1 and simply removing and reseating U1 will correct that condition, or it could be that there is a marginal solder connection on some path (that is actually the most likely possibility). All in all, try using the schematic and attempt continuity checks that include the greatest possible number of soldered connections will go a long way toward detecting marginal components and solder joints. Many bad solder connections seem to work fine until 6 month to a year after assembly and then 'mysteriously' fail, do not overlook that possibility. Component failure does happen but it is rare. 73, Don W3FPR > -----Original Message----- > > Gents, > I have a K2 Serial 5375 which has performed perfectly since > completion 5 months ago, unfortunately it has recently developed a > fault I need some advice on. The fault which causes the rig to > function on 160m 30m &15m only is intermittent.I have found when the > fault is active that K13 remains in the reset state, I can usually > clear the fault by making several band changes or cycling the power a > few times which puts K13 in the proper state for the selected band. I > have checked all soldering around RF U1 & the relays to no avail. When > I removed the control board to reset the relays I found powering on > did not cycle the relays as per fault finding guide.I feel the problem > is probably U1 or k13 but would appreciate advice on isolating the > fault further. > > Regards Graham G4cpd > _______________________________________________ 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 _______________________________________________ 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
