Just a couple comments from one long in the tooth. Vacuum relays will last forever if switch unloaded, that is no RF current flowing. I have built many industrial power sources and never replaced a vacuum relay, UNLESS, the control sequence failed and allowed either power to be applied before the switch was closed or while the RF current was still flowing. Answer, VERY careful sequence keying even in QSK will let the relays last forever. While replacing the relay do a dry logic check of the keying sequence in time. Make sure you don't have a horse race to failure. IMHO. Cheers, Mel, K6KBE
--- On Sun, 10/28/12, Gary Smith <g...@ka1j.com> wrote: From: Gary Smith <g...@ka1j.com> Subject: Re: [Elecraft] K3 and sticking amp T/R relay To: Elecraft@mailman.qth.net Date: Sunday, October 28, 2012, 3:11 PM It's an old Alpha of the 77DX/SX clan. Unfortunately there's nobody I know of around here that knows these amps & it's too heavy to ship so I'll have to do my best and amp repair/schematic wrangling is not my strong point. There is a Kilovac relay in there and Alpha always used jennings so someone has been into that section and I can't tell by looking at it if modifications have been made other than to put in a different relay. The HC-1 Kilovacs were as I recall a drop in part for the Jennings RJ1A. It seemed to work fine at QSK but if the sequencing is wrong it could hot switch. I'd love to have PIN diodes if I had an ideal SWR, nothing like totally silent keying. Since they do suffer the SWR gremlins, I have no wish for them in any amp. Maybe I should move the K3 delay to 20ms for the time being. Gary KA1J > Hi Gary, > > A vacuum relay you say? They are supposed to be fast (like < 8 ms) but > the old amp might delay its closure for some other reasons. The > ACOM-1000, ACOM-2000 and ALPHA 86 use a vacuum relay and do QSK. > Guys curse ALPHA87A PIN diodes which at $80 each (multiple ones used) > pop if too high an SWR is encountered. They are a bear to physically > get at. So relays are good...... > > What kind of 30 year old amp? > > Vacuum relays do indeed fail and contacts get sticky. It might be a > replacement is all you need. > > Hope you suffer no ill effects from Sandy. It turned out to be a > non-event here on the S side of the NC/VA border about 75 miles from the > coast. > > 73 de Brian/K3KO > > > On 10/28/2012 21:19, Gary Smith wrote: > > My TX DLY setting is 015. If I've got it this high and I still had a > > problem, this makes it difficult for me to know what to do; I use QSK > > much more than any other mode/setting as I chase DX and do not want > > to transmit while the DX station is replying to someone & hopefully > > me. I can use semi but I miss a lot doing that. > > > > I do need to try and spare the amp from damage, I'm going to replace > > the Vacuum relay as now that it's stuck once, I expect it will happen > > again only sooner. > > > > Oy! > > > > gary, KA1J > > > > Now to go to the salt marsh and try to elevate my remote coax switch > > & get it away from the Storm Surge that will surely swamp it during > > Hurricane Sandy. > > > > > >> Do this at the risk of QSD CW. Higher settings (>10ms) cause this. > >> The bad keying is independent of internal or external keyer. > >> > >> It is a bug that has never been fixed in the K3. > >> > >> 73 de Brian/K3KO > >> > >> > >> On 10/28/2012 3:23 PM, Don Wilhelm wrote: > >>> Gary, > >>> > >>> The config menu TX DLY parameter will change the time from keydown to > >>> the onset of RF. > >>> > >>> 73, > >>> Don W3FPR > >>> > >>> On 10/28/2012 4:09 PM, Gary Smith wrote: > >>> > >>>> My question for here is; if the amp is not properly sequencing with > >>>> the K3, what setting can I change within the K3 to provide more time > >>>> for the amp's relays to close before the K3 transmits? I remember > >>>> there was a feature to allow ms changes for QSK in the K3. How do I > >>>> find that option? And should I decrease the MS time in the K3 or > >>>> increase it to let the perhaps relay in the amp have time to close > >>>> first to avoid hot switching? > >>>> > >>>> > >>>> > >>> ______________________________________________________________ > >>> Elecraft mailing list > >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft > >>> Help: http://mailman.qth.net/mmfaq.htm > >>> Post: mailto:Elecraft@mailman.qth.net > >>> > >>> This list hosted by: http://www.qsl.net > >>> Please help support this email list: http://www.qsl.net/donate.html > >>> > >>> > >>> ----- > >>> No virus found in this message. > >>> Checked by AVG - www.avg.com > >>> Version: 2012.0.2221 / Virus Database: 2441/5359 - Release Date: 10/28/12 > >>> > >>> > >>> > >> > >> ______________________________________________________________ > >> Elecraft mailing list > >> Home: http://mailman.qth.net/mailman/listinfo/elecraft > >> Help: http://mailman.qth.net/mmfaq.htm > >> Post: mailto:Elecraft@mailman.qth.net > >> > >> This list hosted by: http://www.qsl.net > >> Please help support this email list: http://www.qsl.net/donate.html > >> > > > > > > > > ______________________________________________________________ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:Elecraft@mailman.qth.net > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > > > > > ----- > > No virus found in this message. > > Checked by AVG - www.avg.com > > Version: 2012.0.2221 / Virus Database: 2441/5359 - Release Date: 10/28/12 > > > > > > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.2221 / Virus Database: 2441/5359 - Release Date: 10/28/12 > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html