Don, who has probably fixed/built more K2's than would fit in my house, may know of some concrete suggestions, but you can start by checking ALL the solder joints, especially on the control board.
Probably the most common cause of a "failure" in a K2 that hasn't been abused will prove, over time, to be a missed or "cold" solder joint. Elecraft uses plated-through holes, so the wire laying in the hole will make good enough contact for a long time, even several years, before enough oxidation builds up to cause the circuit to open. Then, when it does, it'll be very sensitive to things like temperature that cause things to move about just a tiny bit, greatly affecting the resistance of the unsoldered joint. Tapping on the case would seem to be a sure way to identify a loose connection, but that's not always true. Many parts are tiny and don't have enough mass to move enough relative to the board when the case is bumped. Besides, the fault produced by a loose part is often dependent upon something else going on at the same time that causes that circuit to misbehave, and tapping at other times would show no symptoms. There's the time-honored technique of poking at each part with the rubber eraser end of a pencil, but again you would have to know what else must be going on to cause the fault to occur for that to work. That's why I suggest scouring the board with a strong light and magnifier, one solder pad at a time, looking for either a cold solder joint or a missed solder joint. Actually, there's one thing I'd do first that harkens back to the early computer days you mentioned and why Elecraft avoids I.C. sockets when they aren't necessary: taking ESD precautions, unseat and reseat the firmware to make sure it isn't a bad contact between one of the pins and the socket. I've not heard of that happening on any Elecraft gear so far, but I don't trust sockets beyond the first sign of an intermittent problem. Ron AC7AC -----Original Message----- I am a new owner of an early K2 with Seriel No 638. Initialy rig worked fine, but now a random fault is occuring . I hear a couple of relay clicks (sometimes more) and the display rapidly changes and when stops, the message E137 0.26 or E138 0.26 is usualy given. On one occasion the display was left with St L 071. On other occasionns the display just appears random. Are these error codes, and if so could anyone give me their meaning. The push buttons are non-functional and I can only get back to operation by switching OFF , and then ON. To me, the symptoms are similar to my early computer experiences, when the computer went south. Any recommendations for trouble shooting would be appreciated. The last point is that the problem is chronic during warm up. After 15 to 20 mins the problem is either gone or significantly reduced in magnitude. Thank you, Colin M3WCK _______________________________________________ _______________________________________________ Elecraft mailing list Post to: [email protected] 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
