Don, Thanks for your prompt reply. I think that the problem (if there is one) will only show up after a number of years. Maybe 7 years is the magic figure. It also will depend to a great extent on the quality of manufacture, cleanliness etc. I had a look at the Omron G6H data sheet.
The 100 million operations are the mechanical service life. For the electrical service life you must look under the Characteristic Data. Unfortunately the electrical service life curves only show 2 graphs. One for a 30VDC and one for a 125VAC, both into a resistive load. There is no definitive data presented for when there is no current flow. Like you, I am not sure if these small relays have a wiping action. Perhaps there is a relay expert on the reflector ? Otherwise as you say - only time will tell the true tale. 73 Stewart G3RXQ On Sun, 12 Feb 2006 08:15:24 -0500, Don Wilhelm wrote: > Stewart, > > All I can say is that K2 SN 00020 is working fine after 5 years with no > relay problems, and in all the K2s that I have worked on, I have found only > one relay failure. > > Relay contact failure can also be prevented by using relays that possess > wiping contacts. I know not how much wiping action exists on the latching > relays used in the K2, but they are speced by the manufacturer (Omron G6H > relay data sheet) for 100 million operations with 50 milliohms maximum > contact resistance. The contacts are gold plated silver and I would believe > they should not normally need cleaning by means of a DC bias. > > Perhaps another couple years on the K2 will give a comparison with the > experience with your MP1000 - only time will tell the true tale. > > 73, > Don W3FPR > > >> -----Original Message----- >> ... >> This morning I modified the HPF board to run about 1mA through >> the contacts. >> 10 resistors and 2 caps later - End of problem - Fixed.... >> >> The big relays in the KAT100 should not have a problem, but what >> about the >> smaller ones in the K2, KAT2 ? As far a I can tell a number of >> these have only >> very small AC signals passing through them. None have any DC current flow. >> >> It took about 7 years before the problem surfaced with my >> FT1000MP, I would be >> interested in comments on whether in the same time scale I might >> expect to get >> similar problems with my Elecraft gear. >> >> 73 >> Stewart G3RXQ _______________________________________________ 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
