B7971's

[Nicholas Stock]

http://www.ebay.com/itm/260964813563?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_500wt_1182

Ouch.

I pity the person who bought 2 of them for 600 bucks not that long ago....some people don't seem to do their research on eBay...

Cheers,

Nick

[Cobra007]

Wow, yes that will hurt a bit....
The other ones were NOS if I am not mistaken, but I think these ones
are used. He said they are not soldered but that is probably because
they sit in a socket :-).

Michel



On Mar 2, 11:48 am, Nicholas Stock <nickst...@gmail.com> wrote:
> http://www.ebay.com/itm/260964813563?ssPageName=STRK:MEWAX:IT&_trksid...

[Terry Kennedy]

On Mar 1, 8:00 pm, Cobra007 <mic...@xiac.com> wrote:
> The other ones were NOS if I am not mistaken, but I think these ones
> are used. He said they are not soldered but that is probably because
> they sit in a socket :-).

Despite what is listed by sellers, I have never seen a truly NOS
B7971. As they are run, the background areas around the elements
become lighter. Compare the left (less hours) and right (more hours)
tubes in this picture: http://goo.gl/46gpd

The closest I've ever come to a NOS B7971 was a set that were sold in
the factory styrofoam packaging, but they were still pulls.

The original datasheet (of which I have several) claims a service life
of 50,000 hours. That's at the current they were run at in the
original LECTRASCAN application - they'd likely last a good while
longer in a clock or other modern display that wasn't being run at
full brightness in an office (sometimes even facing the street through
a window!).

[jf...@my-deja.com]

On Mar 1, 7:00 pm, Terry Kennedy <terry+googleb...@tmk.com> wrote:
> Despite what is listed by sellers, I have never seen a truly NOS
> B7971. As they are run, the background areas around the elements
> become lighter.

I agree.

>
> The original datasheet (of which I have several) claims a service life
> of 50,000 hours. That's at the current they were run at in the
> original LECTRASCAN application - they'd likely last a good while
> longer in a clock or other modern display that wasn't being run at
> full brightness in an office (sometimes even facing the street through
> a window!).

I have posted earlier versions of this: In the mid 1970s, I built
three 6-digit clocks with 7971s and based on the CT7001 . They are
MUXed at about 2kHz. So far, they have run nearly continuously for
35-38 years (over 300k hours) with no nixie failures. All of them
were pulls with obvious lightening of the ceramic under the segments
(probably lots of previous use). I would view the 50k in the spec
sheet as a minimum guarantee and not as the time to expect massive
simultaneous failures.

[Nicholas Stock]

That's extremely encouraging! So far, the longest I've run some nixes are my Z568's in my original Jeff Thomas Atomic....continuous for about 8 years now, and they still glow like new (yes, they were NOS when I bought them)!

Nick

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