While a bad connection in the power certainly can cause this, it's worth checking your power supply "crowbar" point. As you know, most power supplies have over-current protection (crowbar circuit) that shuts them down if the current exceeds some preset level, even instantaneously.
Some supplies, like my Astron, shut themselves down completely, requiring me to cycle the power switch on the Astron to restore power and alerting me to just what happened. But others don't. They just shut down for as long as the over-current condition occurs, so all you need do I push the K3 POWER button to restore operation. You are quite right that the current varies according to the SWR. It also varies by band because the overall efficiency of the K3 varies slightly over the bands. I have an Astron 20 which is fine with the K3 but close to the current limit on some bands making it more sensitive to absolutely low SWR on some bands since it draws nearly 20 amps at 1:1 at 100 watts output. Another common issue is an improperly mating Anderson PowerPole connector. It should require a solid "tug" to disconnect the power cable from the rig, indicating that the flat leaf spring contacts are mating fully. One cause of bad mating is that the contacts are not fully inserted into the connector housings. If they are, you cannot remove the contacts by pulling on the wires. The contacts snap over an edge near the open end of the connector when they are fully inserted. Of course that's true for the connectors on the back of the K3 too, but those come pre-assembled and should be right. Ron AC7AC -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jon K Hellan Sent: Thursday, December 04, 2008 6:10 AM To: G4AFU Paul Cc: [email protected] Subject: Re: [K3] [Elecraft] K3 power tripping out G4AFU Paul wrote: > For some unknown reason my K3 (897) tripped out 3 times last night when on > 160m cw. > I was running 90w out with a 1 to 1 swr - auto ATU installed. > Each time I brought it back to life by hitting the POWER button. > > It is a little disconcerting when in mid QSO! > > Has anyone else had this happen to them? This happens to me when SWR is a bit off, and also happened with my previous rig. I haven't measured, but I suspect that it's pulling more current, making the power supply voltage drop. I can usually avoid the condition by turning power back a little - say to 70 or 80 W. The power supply is rated for 25 A. 73 Jon LA4RT _______________________________________________ _______________________________________________ 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
