Dave, I was looking at the PA stage in particular at the time.
Mostly I had on just filament. I suspect that these triodes, even on just filament, probably need a muffin fan or some such, even though Uncle Sam ran these without any cooling. I say this because I've got one 250TH sitting in a socket on the shelf. It has about half of the hours of this radio that *I* have put on it. It is as clear as can be. It looks like THEY ARE GASSY! No question. I'm also trying to get to the mechanism. We know the 4-XXX and up series REQUIRE filament cooling. I'm beginning to think that the triodes need this too! Bob - N0DGN David Hollander wrote: > I have done filament testing in the past year on a large number of > 813's that were supposed to be good. I have had several fill up with > what looked like smoke just with filament voltage applied. They went > right to the trash. > > If you see the white on the glass it is usually a gassy tube. > > Dave N7RK -- +------------------------------------------------------------------+ | AM Amateur Radio Operator NØDGN | +------------------------------------------------------------------+ | Bob Bethman \\\|/// " The absence of a danger | | \\ ~ ~ // signal does *NOT* mean | | [email protected] (/ @ @ /) that everything is OK " | +-------------------------oOOo-(_)-oOOo----------------------------+ ______________________________________________________________ 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
