This has been an interesting thread to be sure. Gentleman I have 3 450TL's that I got from Geoff a few years ago and I have two used known good 250TH's that I have no use for.
I would be willing to trade all 5 for a usable 3-1000Z. The 450TL's are nib box the boxe's are falling to peices. I also have a filament tranny that would work for those 450TL's that I would be willing to throw in. Ronnie - W5SUM Quoting [email protected]: > John Mohn was W5MEU. I remember him talking about that one night over 20 > years ago.I have an old 450TL that I want to use. I guess I need to bring > it up slowly with a variac feeding the filament transformer to keep the > inrush current from wrecking the filament, or is that an issue? > Joe W4AAB > > >> I think there is at least some truth to this Lee, but I am not sure of >> why. By the same token though I have run 250ths for quite some time and >> with many hours of no use both winter and summer without air conditioning. >> They seem to always work the same even though I may only fire them up >> once or twice a year (much to my dismay). So I really don't have any good >> answer for this. If all the tubes in question were assemble into the 610 >> at the same time then maybe you could just pass this off as "it was >> finally time that the air leak got to them". Don, K4KYV and Tim, WA1HLR >> have discussed this sort of thing quite a bit as well as deterioration of >> cathode coatings in both directly heated tubes and indirectly heated >> tubes. You may want to consult with them about this. One thing is for >> certain, if the final tube is weak then it will be very difficult to get >> it to produce a wave form output that matches the audio wave form, and it >> gets worse as the power demand goes up. >> 73 >> John >> >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]] On Behalf Of LEE BAHR >> Sent: Tuesday, August 25, 2009 2:20 PM >> To: Discussion of AM Radio in the Amateur Service >> Subject: Re: [AMRadio] 100TH and 250TH advice and or comment >> >> John Moan (forgot his call and spelling) (SK) in San Antonio used to run a >> few BC-610s. He always rotated his 100TH and 250TH tubes to keep gassing >> from forming in them. He had about a dozen BC-610s and around 17 R-390A >> receivers in his shack. I think he used to say it was bad to lie them on >> their side too. He seemed to know what he was doing and swore the cycling >> of the tubes was neccessary to keep them alive. He claimed storing these >> tubes would kill them in time. I am only talking about 100TH and 250TH >> tubes. >> >> Lee >> w0vt >> Houston >> >> ______________________________________________________________ >> Our Main Website: http://www.amfone.net >> AMRadio mailing list >> Searchable Archives: http://www.mail-archive.com/[email protected]/ >> List Rules (must read!): http://w5ami.net/amradiofaq.html >> List Home: http://mailman.qth.net/mailman/listinfo/amradio >> Post: [email protected] >> To unsubscribe, send an email to [email protected] with >> the word unsubscribe in the message body. >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Searchable Archives: http://www.mail-archive.com/[email protected]/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: [email protected] > To unsubscribe, send an email to [email protected] with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: [email protected] To unsubscribe, send an email to [email protected] with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
