|[AMRadio] 100TH and 250TH advice and or comment|
rbethman at comcast.net
Tue Aug 25 18:53:57 EDT 2009
I'm thinking the thermal cycling, a number of years of use that is for
the most part intermittent, followed by then sitting for another year
and a half has been what broke the back. So long as the intermittent
use was a rather regular periodic interval, I was heating them up and
getting them full use.
I got medical issues that wouldn't let me enjoy the big AM rig, and it sat.
I started trouble shooting a problem, and I find the three of them are
Yet the second radio only got used for about two hours since I got it,
(I can only run one at a time. LOL), and it has now sat for over four
years AND it has NO gassy tubes.
I trying to understand why ONE did and the OTHER did not.
Then it could just be those tubes were going anyway. Although I doubt
it. They all can in the original Mil issue packaging.
It is all strange!
Bob - N0DGN
Brett Gazdzinski wrote:
> I have a modulator that uses four 100TH tubes, it has had the same tubes for
> the last 25 years, they look clear, and work fine.
> I have a bunch of spare 100 TH and TL's, all look ok last I looked...
> I have noticed a bunch of white tubes in the 7 and 9 pin tube stashes, maybe
> the seals fail, the pins rust, or something happens and the air gets in.
> You have a lot of thermal cycling on tubes that get used, from cold to very
> hot, to cold again, but tubes just sitting going bad?
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