Dud Dekatron Query

[threeneurons]

I'm wondering what type of dud dekatrons others have run into. Primarily interested in Russian types.

In general its been found that the high speed (non-neon) dekatrons have a very high dud rate. Personally, none of my Ericsson GC10D, nor GS10D tubes work. No Gas; gone to air, just by sitting on the shelf. A little more than half of the 6909 and 6910 tubes are duds. In the past, all of the Russian OG-3 tubes I've had were good. 

Until yesterday. I bought 4 OG-3 tubes, and tested them when I received them, about a month ago. I got them to verify that they would actually work in my spinner kit, which they did. But yesterday I powered up a spinner, with an OG-3, that had been sitting there, off, for most of the month. It didn't light up. The board was otherwise, working properly. I swapped in another OG-3, and it works fine. I then placed the questionable tube near a spark generator. Instead of glowing, it had the tell tale sign of air.

It could be that the tube had some kind of isolated defect, which finally let air in. OR, it could be that Russian "high speeds" (of which an OG-3 is) are subject to all the ills of other high speeds. It could be both. This particular tube has a mechanical defect, but it would "dud-out" in time anyways. I just want to know what other people have experienced with these tubes. OG-3, OG-7, and OG-8 in particular.

[AnubisTTP]

I have bought around 100 OG3 tubes over the years and I would say that
about 25% of them have been duds, mostly from gas loss but some with
shorted cathodes and similar manufacturing errors. That said I have
never had an OG3 fail after it comes into my hands, as is common with
the 6909 and 6910. Apparently once the tubes are rescued from whatever
corrosive government surplus warehouse they were stockpiled in in
Russia, they hold up alright. The OG7 seems to have about the same
failure rate as the OG3, though I have had one of these tubes fail in
storage and I have never had an OG3 fail in storage The OG4 is rock
solid, I have never had one fail, and very few of them show up from
Russia with defects it seems. The more exotic Russian high-speeds (the
OG8 and A106 mainly) seem to have extremely high failure rates and
should be avoided by everyone except the dekatron completionist. Every
single OG8 I have bought, from multiple sellers over the past five
years, has been defective except for one. The A108 and A109 appear to
have about a 10% defect rate from the factory based on the lots I have
bought, but don't seem to fail in storage; at least I have never had
an A108 or A109 fail on the shelf and I have a number of them.

Richard Kline
http://www.decadecounter.com/

[Tidak Ada]

What is kown about the ELESTA EZ10B and outgassing ?

eric

Richard Kline
http://www.decadecounter.com/

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[AnubisTTP]

The EZ10B is filled with hydrogen and seems to be incredibly unstable,
of the 10 I have bought over the years, six were DOA and another one
failed in storage. The EZ10A is filled with argon and seems to fare
much better from what I have seen, although I have still had a few
show up outgassed from Ebay I have never had one fail in storage.
Strangely, the ECT100, which is another hydrogen filled counter made
by Elesta, seems to be stable; the 13 that I have handled have all
been fully functional.

Richard Kline

[Jon]

On Mar 17, 5:43 pm, threeneurons <threeneur...@yahoo.com> wrote:
> I'm wondering what type of dud dekatrons others have run into. Primarily
> interested in Russian types.
>
> In general its been found that the high speed (non-neon) dekatrons have a
> very high dud rate.

My experience is broadly similar. OG3, OG7, OG8, GC10D and GS10D are
all somewhere between 50% and 75% dead rates. The 6909 and 6910 are
similar, probably towards the top end of that range. The Elesta tubes
also have an appreciable number of duds, but not as many.

The worst one of all in my book is the high-speed Mullard Z505S - I
have one working example and lots of dead ones. Well I hope the
working one is still OK - it's been a few months since I checked...

At the other end of the spectrum, the ETL low-speed neon dekatrons are
as tough as old boots. Don't think I've ever seen a dead one, other
than due to mechanical trauma.

Jon.

[Tidak Ada]

Just received a DGL-Pressler N3, very low speed (25 kHz) dekatron. Was quite
expensive, so I hope it will work. Anyhow it is neon filled, so if well
manufactured it will not be outgassed.
Never saw a photo of video of it while working, so an challenge.

I know all tubes filled with hydrogen and helium (mixtures) are prone to
outgassing, because glass is permeable to these gasses. Even hydrogen
thyratrons, however they contain a kind of buffer getter to keep the
hydrogen pressure for a longer time ant the necessary level.

eric

-----Original Message-----
From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On
Behalf Of Jon
Sent: zaterdag 17 maart 2012 23:07
To: neonixie-l
Subject: [neonixie-l] Re: Dud Dekatron Query

Jon.

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