First time I've seen anything like this.

[Winky Dink]

I've been retesting boxes of old tubes and attempting rejuvenation on some of them. A couple of nights ago, this happened:



For the safety of my equipment, I should have just cut the power and left it alone. But I couldn't resist repeating it to get a quick video:

https://flic.kr/p/2hcncrU

I won't give you any more information. The photo and video are unaltered. Who can guess what's happening?

[jr_tech]

82 or 83 mercury vapor full wave rectifier?

jr

[bandersen]

Ditto. Those dark splotches around the bottom of the glass envelope look like condensed mercury.

[Phil]

Its an 83, basically an 80 with mercury vapor. I have an AK radio that uses two of them.

[Winky Dink]

Y'all win. I lose. I bought this in March 2013 as an 80 and first tested it 25 January 2014. It tested 'good' and I put it away. BUT...I put a sticker on it that says "World Tube/Used/Mar 20013/No ID on Tube." It didn't light up then like it did in the photo and video. I got the 83 data sheets and retested the tube. Heathkit TT1 settings are virtually the same for the 80 and 83. I can see some constant blue now, but after multiple tests, I only got one blue flash for a second. I took some new photos and will take some more when it's dark.

[Sandy G]

Well, it DESERVES to go out in a Blaze of Glory.... You have any way to put power to it, put it atop a fencepost & shoot it w/a 22 ? If you could do THAT after dark, it MIGHT put out a Real Show for ya....Yeah, I know... I'm SICK....

[MadMan]

So if it's got mercury, is it supposed to do that? Or is that just a result of the testing procedure? Cuz I believe mercury arc rectifiers do that normally, but idk what this tube does.

[Winky Dink]

No, it's not supposed to look like the video. I Suppose that's a result of keeping it on the shelf for 6 years--maybe bits of mercury sticking to the glass or the filament burning off some elemental mercury. After the video was taken the tube returned to normal. Normal looks like this:



This photo was taken in the tube tester. If I switch to the other plate, the blue switches to the opposite side.

[jr_tech]

So after some “warm up” time has more mercury vaporized?

jr

[Electronic M]

That's pretty....If that is interchangeable with an 80 it might be cool to install it in a set where you can see it in operation.

[bandersen]

An 83 can glow blue during normal operation but generally just down inside the plate structure.

83 draws 3A filament while an 80 is 2A. Also 83 has a lower voltage drop across the plates and generates more electrical noise. So it's not a drop in replacement but can sub for an 80 in some cases.

[jr_tech]

Originally Posted by Electronic M

That's pretty....If that is interchangeable with an 80 it might be cool to install it in a set where you can see it in operation.

Take a look at the light show produced by six 866s and a couple of smaller mercury vapor tubes in this 1 kW audio amp.

https://m.youtube.com/watch?v=G7qMVYf85sM

jr

[AlanInSitges]

Originally Posted by jr_tech

take a look at the light show produced by six 866s and a couple of smaller mercury vapor tubes in this 1 kw audio amp.

https://m.youtube.com/watch?v=g7qmvyf85sm

jr

ybmti!

The filaments on those output tubes draw 14A each.

[Tim Tress]

One big use for the 83 is in the Hickok TV-7, 600/600A, 6000/6000A, and similar tube testers. The 866 was used in a great many broadcast and Ham transmitters, as well as in big audio amplifiers for indoor and drive-in theatres. I think that I still have some downstairs.