Does this mean my 21AXP tube has gone to AIR???

[Tubejunke]

You mentioned having another tube which the tester worked fine on. If that means you have another set, just position them butt to butt and hook up the socket from another set. See what happens.

B.T.W. I am fairly certain that Mr. Thomas Edison had some of the same questions with the early incandescent lamp. A quick read on that would answer questions about why heaters burn out in open air. That aside, I don't get why a tube without open heaters and gone to air would do much of anything more than give you a momentary light show before pretty quickly opening up presenting NO load to the test instrument.

Perhaps these old things are more robust than I give credit for. Phil Nelson's story contradicts my thoughts all together. I don't think anyone mentioned the number of times these tests were done; or duration. Seems like it would be a one time thing....

[Phil Nelson]

I didn't keep time with a stopwatch, but I tested the tube multiple times, for a few minutes each time. I didn't want to believe it was really bad, and I have had a number of tubes that gradually "woke up" after sitting on the tester for a while. I also tested the filament for continuity more than once, again, not wanting to believe my eyes. The white getters convinced me I was wasting my time on a gone-to-air tube. The visible rust on the tube elements is also consistent with air (and moisture) getting inside.

That's a sample of one, so take it for what it's worth

Phil Nelson

[Tubejunke]

Originally Posted by Phil Nelson

The white getters convinced me I was wasting my time on a gone-to-air tube. The visible rust on the tube elements is also consistent with air (and moisture) getting inside.

That's a sample of one, so take it for what it's worth

Phil Nelson

Makes all the sense in the world. I am hoping that my statement, "Phil Nelson's story contradicts my thoughts all together. I don't think anyone mentioned the number of times these tests were done; or duration." was not misconstrued as being flippant.

I meant it as a general thought on the thread and the info. we had at the time. The number of times tested was more toward the thread starter, and the rest just my surprise that the heaters don't just burn out pretty darned quick, so I questioned duration on RCA2000's tests.

Phil's deduction of his tube gone to air with the rust and white getter inside. I pretty much write anything with white getter to be pretty much garbage. No harm done I hope.

[Phil Nelson]

Originally Posted by Tubejunke

I meant it as a general thought on the thread and the info. we had at the time.

It's a reasonable question, and I had wondered, too, why my filament didn't burn out right away. Maybe jr_tech's idea is correct -- the tester's supply was bogged down.

Phil Nelson