Re: [neonixie-l] Another newly-manufactured nixie tube

['jf...@my-deja.com' via neonixie-l]

Before you get too excited, that is probably Chinese yuan (aka renminbi), 
so it would be closer to US$110.

On Tuesday, June 2, 2020 at 2:32:13 PM UTC-7, Terry Bowman wrote:
>
>
> If the colon tube is the ¥749 item that's slightly less than $7. That's 
> downright cheap and at first glance they look rather nice. The dimensions 
> are 110mm x 15mm. That's 4.33" x 0.6'.
>
>
> Terry Bowman, KA4HJH
> "The Mac Doctor”
>
> "Never install version point-zero of anything"
>
>

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Re: [neonixie-l] 1961 Heathkit Catalog

['jf...@my-deja.com' via neonixie-l]

That is a lot of mercury.  I don't think we kept more than a pound.  Also, 
I don' tknow how you get the Hg completely out of the pan, since ISTR that 
we would use the Hg to shine up nickels and pennies.

On Wednesday, May 27, 2020 at 7:46:33 AM UTC-7, Ira wrote:
>
> Get a pan off of the stove that you use to cook in every day, pour it in 
> there, THEN stick your hand in it. After playing with it, pour it back into 
> the flask, and put the pan back on the stove. Problem solved!!!Ira.
>
>
>

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[neonixie-l] Re: Is it possible to identify a single nixie?

['jf...@my-deja.com' via neonixie-l]

In addition to photons and cosmic rays, illuminating other elements can 
also promote the firing (isn't that the reason for the "keep alive" on the 
Panaplex?).  

It has been a long time since I did it, but ISTR that you could stay on the 
negative resistance branch by aggressively limiting the current.  In the 
olden days, that was using bigger resistors, but nowadays I would build a 
transistorized variable current regulator.


On Wednesday, May 27, 2020 at 7:05:48 AM UTC-7, gregebert wrote:
>
> I had a very difficult time trying to measure the firing voltage, probably 
> due to photons and other particles whizzing around the workbench. 
> Typically, it was about 10-15 volts higher than the smallest measurable 
> current where I could see any hint of glowing. The value varied from 
> reading-to-reading.
>
> I recall that I could not repeatedly/predictably measure currents below 
> 100uA, because the segment would just extinguish and the current went to 
> zero.
>
> Whenever I get my last 2 R|Z568m tubes, I'll spend more time on ionization 
> measurements. Right now, those tubes are still waiting on a dock or tarmac 
> to get shipped to the US.
>

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Re: [neonixie-l] 1961 Heathkit Catalog

['jf...@my-deja.com' via neonixie-l]

We kept ours in an Erlenmeyer flask, and I could never get my hand past the 
bottleneck.

On Wednesday, May 27, 2020 at 1:06:26 AM UTC-7, Terry Kennedy wrote:
>
>
> I grew up in a time where in elementary school you got to dip your hand up 
> to the wrist in a bottle of mercury,
>

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[neonixie-l] Re: Is it possible to identify a single nixie?

['jf...@my-deja.com' via neonixie-l]

Over that voltage range, I would expect three branches on the IV.  Did you 
also track the firing voltages and extinction currents?  Dark rooms vs 
well-lit?  Ambient temperature?

On Friday, May 15, 2020 at 8:57:08 AM UTC-7, gregebert wrote:
>
> Yes; for a given segment, there are tube-to-tube variations in segment 
> current for a given voltage.
> The data below is for 8 tubes, for segment #1.
>
> At 200uA, the voltage varies from 127 to 138V. At 6mA, the voltage varies 
> from 169 to 181V
>
> Using just a resistor for setting the current will result in large 
> variations across tubes and supply-voltage. That's why I use 
> current-regulators on each cathode. It's probably overkill, but given the 
> ridiculous pricing for b7971's, I'm not taking any chances. I have no 
> spares for my 8-tube clock; just 2 tubes that have a shorted or dead 
> segment.
>
> I have no idea what happens over time, but I suspect that as tubes age the 
> current, hence the brightness, decreases for a given voltage. In a few 
> years, I will retake the data and see what has happened. This clock went 
> into service in 2017.
>
> 0.2 0.5 1 2 3 4 5 5.5 6  <-- Current
> 130 133 138 145 152 159 167 170 172  <--- Tube 1
> 135 138 143 151 158 166 174 178 181
> 134 137 142 150 158 166 174 178 180
> 138 138 140 145 151 158 164 169 172
> 137 138 142 148 156 163 172 176 180
> 135 136 140 147 154 162 171 174 177
> 131 134 138 144 151 158 166 170 173
> 127 130 134 141 147 155 162 166 169 <--- Tube 8
>
>

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[neonixie-l] Re: Is it possible to identify a single nixie?

['jf...@my-deja.com' via neonixie-l]

Based on my experience, you should expect at least another 300k hours even 
if you "overdrive" them.   That said, I don't remember anyone reporting a 
natural death from old age and excessive usage.

On Wednesday, May 27, 2020 at 1:44:43 AM UTC-7, Terry Kennedy wrote:
>
>
> B7971s are amazingly robust. The MOD-SIX in the room where I'm typing this 
> reports 76,571 tube-on hours 
>

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Re: [neonixie-l] 1961 Heathkit Catalog

['jf...@my-deja.com' via neonixie-l]

It was meant as a joke.  I still use SnPb eutectic solder, and I think my 
~1 kg is a lifetime supply  I think I can blame this for my dumbness, since 
I used to hold the solder in my teeth during construction and repair.

I have this religious belief, scientifically not proven, that Pb-free 
solder made some of the surface-mount boards in my car less reliable.  
There were some medium-power current-limiting resistors where one of the 
solder joints eventually cracked ad left an open circuit.  I blame this on 
the ROHS solder being more brittle and the thermal cycling eventually 
fatiguing and cracking the solder after 5-10 years.

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Re: [neonixie-l] 1961 Heathkit Catalog

['jf...@my-deja.com' via neonixie-l]

With modern ROHS requirements, you will need to build it with lead-free 
solder.

On Friday, May 1, 2020 at 5:27:11 AM UTC-7, Bill van Dijk wrote:
>
> Michail, I have an unbuilt Heathkit 5MHz model IO-4105 scope kit, in 
> original box. Picked it up at a flea market a couple of years ago!
>
>  
>
> Bill
>
>  
>
> *From:* neoni...@googlegroups.com  [mailto:
> neoni...@googlegroups.com ] *On Behalf Of *Michail Wilson
> *Sent:* Friday, May 01, 2020 12:07 AM
> *To:* neoni...@googlegroups.com 
> *Subject:* RE: [neonixie-l] 1961 Heathkit Catalog
>
>  
>
> Count me in.
>
>  
>
> I’d like to group buy for a price break.
>
>  
>
> I’m thinking the garage door opener on page 23.
>
> Sorry, no need for the extra remote for $25.  No one is rich enough to 
> have a second car, but a nice option for those super rich.
>
>  
>
> Ok,,…ok… On a serious note.
>
> I’ll take the scope on page 94.  I hear in about 40 years, you can convert 
> to a clock.
>
>  
>
> Michail Wilson
>
> 206-920-6312
>
>  
>
> *From:* neoni...@googlegroups.com   > *On Behalf Of *martin martin
> *Sent:* Thursday, April 30, 2020 8:42 PM
> *To:* neonixie-l >
> *Subject:* [neonixie-l] 1961 Heathkit Catalog
>
>  
>
> Since we all seem to have time on our hands... 
>
> Let's order some Heathkits!
>
>  
>
> Time to go on the "Way Back Machine" and make your orders!
>
>  
>
>
> https://www.americanradiohistory.com/Archive-Catalogs/Allied-Catalogs/Heathkit_1961_Fall_Winter.pdf
>
>  
>
>  
>
> -- 
> You received this message because you are subscribed to the Google Groups 
> "neonixie-l" group.
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> email to neoni...@googlegroups.com .
> To view this discussion on the web, visit 
> https://groups.google.com/d/msgid/neonixie-l/4300122e-515c-418a-9cb4-7d17102fe9c7%40googlegroups.com
>  
> 
> .
>
> -- 
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> https://groups.google.com/d/msgid/neonixie-l/MW2PR0102MB343545CF70DA59FCA018039F82AB0%40MW2PR0102MB3435.prod.exchangelabs.com
>  
> 
> .
>

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Re: [neonixie-l] Re: MPSA42 or MJE340?

['jf...@my-deja.com' via neonixie-l]

As a matter of personal taste. I like to have a generous margin on BVceo, 
like always larger than Vcc.  To me, anything else is penny wise and pound 
foolish, especially in hobby quantities.  I always use transistors rated at 
300V even if my Vcc is less than 200V.

Gregenert is probably right about amplified leakage, but another 
possibility is that you have avalanche breakdown of the CB junction in the 
driver transistor.  Given the nonlinear IV of neon, this might mean that 
your lamps are off when you first apply power, but it will not turn off on 
command.

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Re: [neonixie-l] clock with Sperry SP-151

['jf...@my-deja.com' via neonixie-l]

I agree.  I forgot that one of the first things you should do is apply HV 
(like 150-200V) directly to the tubes,with a series dropping resistor of 
47K-220K, and make sure it glows under these conditions.  I realize that 
this assumes you have access to an electronics lab...

On Saturday, April 25, 2020 at 10:48:28 AM UTC-7, gregebert wrote:
>
> The SP-151 is durable;
>

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Re: [neonixie-l] clock with Sperry SP-151

['jf...@my-deja.com' via neonixie-l]

Also, as I think about it, there is a "keep alive" element, and you should 
make sure it is energized at all times. 


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Re: [neonixie-l] clock with Sperry SP-151

['jf...@my-deja.com' via neonixie-l]

I had one of these evaluation kits, and I recall that the displays were 
socketed.  If you have an oscilloscope, you should do some basic 
debugging.  I would start at the power supply (one of my nixie clocks used 
a Signal Transformer of the same vintage that died due to an open 
primary).  If you have all the proper dc voltages, I would next check the 
logic level signals: the 60 Hz reference and the MUXed segment and digit 
drives.  Finally, check for proper waveforms at the anodes and cathodes.  
Since nothing lights, I would suspect a bad power supply or a construction 
error like swapping the pnp and npn transistors or backwards diodes.

I have mentioned this before, but the MM5314 does not have very good noise 
rejection on the clock reference input, so power line spikes tend to make 
it run fast.

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Re: [neonixie-l] MPSA42 or MJE340?

['jf...@my-deja.com' via neonixie-l]

It should be easy to convert the 575 back into a tube curve tracer since it 
was a modified 570 with the filament transformer removed and the sockets 
changed.  If you can find a meterless Hickok tube tester, you have the 
sockets, switches and filament transformer you would need to convert it 
back for a single tube.  It can obviously be done by brute force, but I 
have not figured out a clever way to set it up to do A-B comparisons so you 
can find matched pairs.  Some other things you might have to add are power 
supplies for the screen and suppressor and the other elements you might 
find in a pentagrid converter (or you could derive these from the voltages 
applied to the other elements).

On Friday, April 24, 2020 at 10:00:29 PM UTC-7, Ira wrote:
>
> I have a couple of 575 that I might sell, either as is, or reconditioned 
> and calibrated (not inexpensive), with an operators manual. I also have the 
> 575 mod 122C which sports a 400V collector sweep power supply. The audio 
> people are crazy over them because they can be converted for TUBE curve 
> tracing. If interested contact me OFF of this page.   Ira. 
>
>

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Re: Re: [neonixie-l] MPSA42 or MJE340?

['jf...@my-deja.com' via neonixie-l]

You might have to settle for one of the more modern transistorized curve 
tracers.  In the last century when 500-series scopes were going for 
$20-$50, I remember talking to someone at one of the ham swaps.  He said 
that they were being bought up and cannibalized by the audiophools because 
they were full of 12AX7s and other coveted tunes.

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Re: Re: [neonixie-l] MPSA42 or MJE340?

['jf...@my-deja.com' via neonixie-l]

Sure, but based on the similarities in the Central Semi data sheets, the 
same die appears to be used interchangeably.  So the factors I can imagine 
is that they select and direct the leakier parts to the TO-220 package, or 
that the TO-220 package makes a difference (like allowing a higher junction 
temperature before the chip will self-destruct, or an intrinsically leakier 
package), or that the MJE is allowed to be exposed to more adverse circuit 
conditions (and they would have the same leakage in the same circuit).  
Otherwise, I lack the imagination to conjure up other plausible differences 
as long as they use the same chip.  Or maybe other manufacturers do not use 
the same chip for both part numbers, and Central decided that using their 
MPS-A42 chip would not violate the Icbo promises for the MJE-340 (from 
Motorola since Central is a second source).  If I had parts from several 
companies, I would be even more motivated to open them up and compare.

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Re: Re: [neonixie-l] MPSA42 or MJE340?

['jf...@my-deja.com' via neonixie-l]

Is there a 1000X difference in the gain?  Across all lots and all operating 
conditions, I would have expected less than 10X.

On Thursday, April 23, 2020 at 3:56:44 PM UTC-7, gregebert wrote:
>
> Much of the additional leakage current is caused by the higher DC gain of 
> the MJE device; the datasheet says gain peaks around 240.
>
> Basically, the reverse-leakage current from the collector-base junction 
> gets amplified by the DC gain (beta), to produce the overall leakage (Icbo)
>

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Re: Re: [neonixie-l] MPSA42 or MJE340?

['jf...@my-deja.com' via neonixie-l]

On Thursday, April 23, 2020 at 3:10:36 PM UTC-7, gregebert wrote:
> I'm absolutely certain the MJE die is physically larger. For one thing, 
it must conduct more thermal energy to the case.

I am inclined to agree, but if it were me, I would be willing to invest 
$1.08 and a half hour in the experiment.


> Another tip-off is the difference in DC current-gain, and that in-turn 
accounts for part of the 1000x difference in leakage 
> current.  I believe leakage current is directly proportional to the area 
of the base (my device physics textbook is at work,
> and I'm at home recalling a class I took in 1983...); the actual 
leakage-current density is an exponential equation based
> on all sorts of properties of the silicon.

All other things being equal, I would expect leakage to be roughly 
proportional to the chip are, which would not account for the 1000X.  Also, 
some specs in the data sheet are very loose, like guaranteed maximum 
leakage.  If the base and emitter are both diffused, I would expect these 
variations to swamp out the area.  How do they get the HV capability?  If 
it is an epi base layer, there would be variations due to the quality of 
the epitaxy that could affect the leakage.  That is a long way of saying 
that you might be right, but I don't know.


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Re: Re: [neonixie-l] MPSA42 or MJE340?

['jf...@my-deja.com' via neonixie-l]

 

So this is a matter of academic curiosity and not an effort to make your 
device work.  I think this is a neat thing to do.  Based on your 
observations, this suggests some experiments.

 

In a previous post, I speculated that both part numbers might use the same 
chip.  I now think this is less likely.  Since this would be a destructive 
test, this should be done after all the other experiments.  You can expose 
the silicon chip by using wire cutters to scrape away the epoxy.  The chips 
will usually be bonded to the collector lead.

 

If they do use the same chip, the difference could be due to a higher 
temperature in the smaller package.  I would try using some canned Freon to 
chill the MPS-A42 to see if this changed its performance.

 

Another less likely possibility is that this is the natural variation in 
the chip processing.  You test this by comparing several parts with 
different date codes.

I am sure that creative minds can conjure up other hypotheses.

On Wednesday, April 22, 2020 at 8:03:34 PM UTC-7, Paul Andrews wrote:
>
> 
>
> Or me? Well, the MJE340 is in a larger package, but other than that, 
> nothing. 
>
>  
>

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Re: [neonixie-l] MPSA42 or MJE340?

['jf...@my-deja.com' via neonixie-l]

What do you have against the MJE340?  Is it too large?  Is it too much more 
money (onesies retail in Silicon Valley is 34 cents versus 75 cents)?  If I 
had to go out and buy new parts in hobby quantities, I would get the MJE340 
and not invest any more brain power, but if it was going to be used in 
quantities of thousands I would choose more deliberately.  If I already had 
some MPS-A42's on hand, I would wire it in to the circuit and test to see 
how hot it gets, and switch to the MJE340 if it got noticeably warm. Oor 
you could do the Spice modeling and formal thermal analysis.  Actually, it 
would not surprise me if you opened them up and found that they used the 
same chip and differed only in the massiveness of the packages.


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[neonixie-l] Re: MPSA42 or MJE340?

['jf...@my-deja.com' via neonixie-l]

I would say whichever is cheaper, keeping in mind that nothing is cheaper 
than free from the junque box.  I used the floor sweepings  (advertised as 
npn 300V and 10W) from Poly Paks, and none of these have failed yet.  I did 
have one genuine Motorola MPSA92 fail after 40 years of service.  Just make 
sure you are driving your transistors into saturation.  Obviously TO92 is 
smaller than TO220, and this might be a factor in your application.


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Re: [neonixie-l] Discovered an old advertisment

['jf...@my-deja.com' via neonixie-l]

My tubes were over driven by 2X-4X compared to the maximum values in the 
B7971  data sheet:   HV=-195V, cathode resistors=430ohms, MUX duty cycle = 
12%.  After running 24/7 for 40+ years, the tubes are very slightly dimmer 
than the tubes I had kept as spares with a slight color shift.  (You can 
see this color shift in the PEOPLE LIKE NEON movie at the top of this news 
group, where tube #3 has some pink in addition to the orange glow.  My 
spare tubes also glow slightly pink, while all the old tubes are uniformly 
orange.)  After 40 years, the only significant change was darkening on the 
inside of the glass and on the back plate under the segments that I used 
(in a seven segment display mode).  There were two clocks, and the 
darkening on the glass in each set was uniform, but it was more pronounced 
in one of the sets; I suspect this may have been exacerbated by the amount 
of overdrive.  

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Re: [neonixie-l] Discovered an old advertisment

['jf...@my-deja.com' via neonixie-l]

You probably learned a lot more about electronics by having and using that 
scope, so I think it was the better investment.

On Friday, April 3, 2020 at 4:52:56 PM UTC-7, Robert G. Schaffrath wrote:
>  ... though in hindsight, the tubes would have been the better 
investment. 

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[neonixie-l] Re: Discovered an old advertisment

['jf...@my-deja.com' via neonixie-l]

I really don't remember anything other than Burroughs brands on the 30+ 
tube I bought, but it has been 40+ years for most of them.  I recently 
repaired two clocks for non-Nixie failures, and between the 12 in those two 
clocks and the 6 that I swapped in on general principles, I only remember 
seeing Burroughs.  I have no reason to believe that any of them were NOS, 
and I assume they were all pulls (since I would have been too impoverished 
to pay the premium for NOS).  Maybe the Ultronics branded tubes were in the 
newer displays.  BTW, was Ultronics the only manufacturer to use B7971's in 
their products?

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[neonixie-l] Re: Discovered an old advertisment

['jf...@my-deja.com' via neonixie-l]

How could you tell they were NOS?  I have this religious belief that 
everything on the surplus market consisted of NYSE pulls, as suggested by 
the words "removed from operational equipment".  Did your NOS actually come 
in Burroughs boxes marked with the tube type, or were they just covered in 
bubble wrap?  Did they look any different than the ones you got with the 
boards?

On Friday, April 3, 2020 at 7:44:07 AM UTC-7, Robert G. Schaffrath wrote:
>
> Yes, Meshna is where I got three boards from in 1979 and later on my seven 
> NOS tubes. By 1980, the prices had almost doubled (used tubes were USD$4 
> and NOS were USD$5) which is understandable 
>

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[neonixie-l] Re: Discovered an old advertisment

['jf...@my-deja.com' via neonixie-l]

Back in those days, the GBP was about US$2, so they were much more 
expensive in the UK.

The tubes were even cheaper from Meshna

I think they were $1/tube with sockets but without the circuit board, which 
is the deal I went for since I was a cheapskate and did not realize that 
the boards had the hard-to-find HV transistors.

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[neonixie-l] Re: Faulty B-7971s

['jf...@my-deja.com' via neonixie-l]

When I had partially it segments, I was able to fix it by increasing the 
anode voltage to about 180-190V.  Others have reported fixing shorted 
segments by hitting the tube, gently; you almost have nothing to lose. 

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Re: [neonixie-l] Re: B7971's on the bay....

['jf...@my-deja.com' via neonixie-l]

So the pictures I intended did not et posted on the Google Groups version.  
The first image is the "fast" picture from 

https://www.ebay.com/itm/VINTAGE-4-Giant-Nixie-Tubes-Working-B-7971-Burroughs-from-NYSE-in-Project-I-made/283830338480?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D6bb3209f1f2b4aab8d6a8c19a575d8ce%26pid%3D100675%26rk%3D2%26rkt%3D15%26mehot%3Dnone%26sd%3D373004734335%26itm%3D283830338480%26pmt%3D0%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3Acd94b89a-71d5-11ea-a388-ce2a8161efbe%7Cparentrq%3A2701e53b1710a128ed0b54acfff90b82%7Ciid%3A1
 


and the second image is the first picture on the left of 

https://www.ebay.com/itm/6-Giant-Nixie-Tubes-Giant-Nixie-Clock-Vacuum-Electron-Vintage-B-7971-Burroughs/174230250318?hash=item2890eea34e:g:ZusAAOSwPyReepUQ

I was going to post a treatise on my comparisons between my 40 y/o tubes 
with "new" ones, but it needs pictures

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[neonixie-l] Re: tiny little counter at a fair price!

['jf...@my-deja.com' via neonixie-l]

On Saturday, March 21, 2020 at 4:33:05 AM UTC-7, newxito wrote:
>
> Nice device, and it uses a 2N3055 transistor!!! I built an amplifier with 
> these transistors 45 years ago, probably the last time I have seen one of 
> them. I remember that they were very popular in Spain in the 1970s.
>

You can still get them in Silicon Valley.  See page 16:  
https://anchor-electronics.com/price-list.pdf , and don't forget the 
plastic equivalents (MJE3055, TIP3055, etc.).

Almost every transistor manufacturer sold them.  I remember reading that 
the 2N3055 spec was so loose that they could re-mark their rejects for 
other part numbers.  Conversely, in most of my non-demanding applications 
(audio amplifiers, power supply pass transistors, etc.), most of the power 
npn transistors (e..g., TIP35)  were interchangeable as long as I did not 
exceed the actual BVceo. 

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Re: [neonixie-l] NL-7094 Price Craziness

['jf...@my-deja.com' via neonixie-l]

On Thursday, February 27, 2020 at 1:14:35 PM UTC-8, Robert G. Schaffrath 
wrote:
>
> ...the whine from the multiplexing bothers me now. ...
>
I reduced the audibility of the acoustic noise by putting the clock inside 
a box made of 1/4" Plexiglas.   This did not do much to reduce the RFI...

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[neonixie-l] Re: Opto Coupler for PWM control - Sanity Check

['jf...@my-deja.com' via neonixie-l]

On Friday, February 7, 2020 at 8:59:19 AM UTC-8, gregebert wrote:
>
> ...Some folks in this group have reported audible noise from 
> multiplexing
>
I am one of the people who reported singing in my multiplexed B7971s.  More 
than 40 years ago, I also had a Panaplex/MM5314 clock that was sold as an 
evaluation kit.  It has been a long time, but I do not remember it 
producing acoustic noise.  Maybe the size of the digits makes a difference 
here.

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[neonixie-l] Re: Question about Heathkit Panaplex Clocks

['jf...@my-deja.com' via neonixie-l]

Do they both run fast?  Designs that simply count the mains are susceptible 
to noise pulses adding to the total, and most early designs were prone to 
this defect. If this is the case, I would try filtering out the noise 
spikes: ferrites on the primary side, and a low-pass on the rectified line 
frequency reference.  (One exception was the CT-700x which could be made to 
run  little slow or fast, depending on the setting of the MUX rate.) 

On Sunday, November 17, 2019 at 3:53:02 PM UTC-8, philthepill wrote:
>
> I bought two different models of Heath Kit clocks with flat planar neon 
> displays.They were both plugged into two outlets on the same AC 
> extension cord and then the extension cord was plugged into a wall 
> receptacle.   One runs as 24 hour clock, other one is a 12 hour clock   
> After a few days they are not at the same time  and the longer they run the 
> further apart they get.  I thought that they both used AC line frequency 
> for timekeeping.Any ideas,  I'm stumped by this.
>
> Thanks  Phil B.
>

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[neonixie-l] Re: B-7971 Smart Sockets - Harwin Socket Pins Vs Original Sockets

['jf...@my-deja.com' via neonixie-l]

...and B-A was generally not the low-cost junque dealer; John Mishna and 
Poly-Paks were usually cheaper.

On Monday, September 30, 2019 at 12:20:48 PM UTC-7, Terry Kennedy wrote:
>Here's the ad (original scan by David Forbes): 

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[neonixie-l] Re: B-7971 Smart Sockets - Harwin Socket Pins Vs Original Sockets

['jf...@my-deja.com' via neonixie-l]

On Sunday, September 29, 2019 at 10:50:16 PM UTC-7, Richard Scales wrote:
> ...
> I too love the B-7971 - if only I had invested when they were super 
affordable - what was I thinking? 
>  
I got mine when they were cheaper than the LED alternative: US$1 per tube 
including sockets, versus about US$5 for a MAN-1.  The disadvantages of the 
nixies was providing the HV power and the cost of the relatively rare HV 
driver transistors (I should have gotten the tubes with sockets and driver 
boards for US$2) compared to direct drive from a 7447.  Naturally, I used 
the sockets, and used point-to-point wiring  on a perfboard (no pcb) which 
automatically provided stress relief n the socket pins.  For three 
six-digit clocks, I have had zero in-service failures after more than 40 
years (so I have not yet needed any of the spares).  My only tube failure 
was when the glass envelope lost a battle with a concrete floor.

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[neonixie-l] Re: B-7971 Smart Sockets - Harwin Socket Pins Vs Original Sockets

['jf...@my-deja.com' via neonixie-l]

ISTR that the real sockets are preferred.  The argument I remember hearing 
is that the pins in the socket "float"; the disadvantage is that you may 
need to jiggle the tube as you insert it into the socket, but the advantage 
is that the pins float and do not stress the glass-to-metal seal thereby 
reducing the probability of creating a leak.  It also means that real 
sockets will better tolerate imperfect pins.  Conversely, rigidly soldered 
pins may cause the tubes to fail prematurely.  Of course, in all cases, 
make sure the pins have been straightened in both cases.

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[neonixie-l] Re: power supplies and radio interference

['jf...@my-deja.com' via neonixie-l]

My three B7971 clocks all produced RFI in the AM and SW radio bands, and I 
kept my radios at least 5m away.  They were based on the CT7001 clock chip, 
so the MUX rate was about 2 KHZ.  The RFI (and the acoustic singing from 
the tubes) seemed to change with the digits displayed.  I assumed that it 
could be blamed on the switching of the HV on the tubes.  Someone once 
suggested that the RFI came from the SMPS, but that is unlikely since I 
used old-fashioned linear supplies.   In hindsight, I realize that I did 
not put a choke on the power cord, which might have helped.  The moral of 
the story is that not all RFI necessarily comes from the power supply. 

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[neonixie-l] Re: What if....

['jf...@my-deja.com' via neonixie-l]

That's what I did: opaque black plexiglas for the sides and the ack, opaque 
white plexiglas for the top and bottom, and clear red for the front.  It 
gives it a mid-20th century modern or Bauhaus look with the digits floating 
inside the box instead of a steam-punk look, and emphasizes its function as 
a clock instead of showing off your hobby construction skills.  The red 
plexiglas is an excellent at producing nearly monochromatic red.

>
>

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[neonixie-l] Re: Nixie collection insurance?

['jf...@my-deja.com' via neonixie-l]

Keep in mind that the insurance company will try to reimburse as little as 
possible.  They might give back the documented purchase price if the tube 
is NIB.  You might be able to argue a higher value based on a recent 
auction sale (think ebay).

For used tubes, they may apply straight-line depreciation over 10 years or 
less, leaving most of them with zero book value. 

Things will be even worse if the policy has a deductible in the $100+ range.


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[neonixie-l] Re: Clocks! Picture sharing....

['jf...@my-deja.com' via neonixie-l]

Back in the old days, a polarizing filter was used to suppress the Fresnel 
reflection.

On Friday, June 7, 2019 at 12:55:20 PM UTC-7, gregebert wrote:
>
> Any tips on how to take good-quality photos ? Mine always turn out looking 
> horrible, partly due to reflections from the various glass surfaces.
> Even with a tripod and minimal sources for reflections doesn't help me 
> much.
>

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Re: [neonixie-l] Interesting nixie item...

['jf...@my-deja.com' via neonixie-l]

Assuming 2000 hours/year, the tubes would have had 20,000-50,000 hours of 
use on them (maybe even a lot more).

On Friday, May 10, 2019 at 3:29:05 AM UTC-7, Paolo Cravero wrote:
>
> On Fri, May 10, 2019 at 12:23 PM Paul Andrews  > wrote:
>
>> EUR? How vintage is it?
>>
>
> It has been relabeled on the front, but not in the back where is spells 
> "German Mark".
>
> Curiously it has probably been in service after year 2002.
>
> Paolo
>
>
>

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Re: [neonixie-l] Re: (12) 16-Pin NIXIE TUBES National Electronics NL5441A Burroughs B5441A Untested

['jf...@my-deja.com' via neonixie-l]

On Sunday, April 21, 2019 at 10:19:03 AM UTC-7, Kevin A. wrote:
>
> . Over 50 bids, most of them the same low feedback bidder. Another 
> sleazeBay special! 
>
> It looks more like a product of the automatic bidding process where the 
lower bids are instantaneously by the previous high bid, with lots of 
hopeful small increases by the lower bidder. 

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[neonixie-l] Re: Nixie clock with the CT7001/FCM7001 chip?

['jf...@my-deja.com' via neonixie-l]

 

I built three six-digit clocks using that chip and B7971 nixies.  I was 
inspired by the article “Behold the Giant Nixie Clock - using a minimum of 
new parts” that appeared on page 70 of the July 1976 issue of 73 magazine.  
This 
can be found on the internet.  That was more than 40 years ago, and all 
three clocks have continued working with zero nixie failures, one failed 
power transformer, two failed electrolytic capacitors, and one failed 
CT7001 chip.

 

>From memory, here are some important differences from the article:

 

The magazine article used a MM5314 clock chip.  The polarities and levels 
for the digit and segment drives are different in the CT7001 (common 
cathode versus common anode configurations), but it was straightforward to 
do the necessary level shifting and polarity inversion.  You need to study 
the data sheets for the two chips.  I vaguely recall that my design 
involved discrete transistors and cascode amplifiers, but that TI later 
came out with suitable HV drivers (75468).

 

I did document my circuit, but after 40+ years and several moves, I doubt 
that I could find it.  Since the clocks all continued to work with only 
easy and obvious repairs, I was never motivated to refer to it.

 

The MM5314 derives its timing from the mains.  Using the circuit in the 
data sheet, it tends to run fast; I think that is because it is susceptible 
to counting any noise spikes on the power line (this might be reduced by 
adding a low-pass filter onto the line reference input).  The CT7001 can 
run slightly fast or slightly slow, depending on the MUX frequency; I 
believe that it uses a PLL and the free‑running frequency of the display 
MUX pulls it.  If I were to do it over again, I would use a variable 
resistor to set the MUX rate and adjust it to minimize the drift.

 

Both of these chips “forget” after a power outage, but the CT07001 will try 
to keep time if there is a battery backup by using its internal MUX 
oscillator.  As far as I know, there is no shortcut in either chip to set 
the time directly, so you have to go through the whole procedure of 
incrementing each digit from its initial state.

 

One additional feature of the CT7001 is the 365-day calendar.  It does not 
automatically do February 29, but setting it manually makes you good for 
the next four years.

 

The nixies in all of my clocks produce acoustic noise and RFI at the MUX 
rate.  Someone suggested it was from my switching power supply, but this 
explanation was unlikely since I used linear power supplies and the noise 
was clearly emanating from the tubes.

 

I was roundly criticized for using the B7971 as “only” seven-segment 
displays since they were so expensive and capable of so much more, while 
the critics considered seven-segment displays to be ugly.  When I bought 
mine, they were $1 each (including sockets) and were cheaper than Monsanto 
MAN-1 displays.

 

An interesting (to me) alternative would be to find a CT7002 and use a 
74141 to drive regular nixies with formed characters.  A more ambitious 
approach would be to use a CT7001 and build a seven-segment-to-BCD decoder 
(this would be an interesting exercise for the student, and I can think of 
at least two different approaches).



On Wednesday, April 17, 2019 at 11:11:41 AM UTC-7, Dekatron42 wrote:
>
> I've come across a few of the CT7001/FCM7001 clock chips which were 
> designed to be used with LED displays and I've been looking for a Nixie 
> clock design with this chip but I haven't found any yet - does anyone here 
> know about such a circuit diagram?
>
> /Martin
>

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Re: [neonixie-l] TESTED 4 Nixie Tubes Burroughs B-7971 3½" tall 14-segment character

['jf...@my-deja.com' via neonixie-l]

On Tuesday, March 26, 2019 at 7:10:17 PM UTC-7, Pramanicin wrote:
>
> I used to think they weren’t proper nixie tubes way back when i got into 
> this hobby. You know, back when they were going for under $20 dollars each. 
> What a muppet i was.
>
> Burroughs called them "Alphanumeric Nixie Tubes" in the data sheet.

I got mine from John Meshna in Lynn MA for $1 each, including sockets,  
back in the mid -1970s.  I think they were $5 for a pair with sockets and  
the board full of HV driver transistors.  Plus shipping, of course.

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Re: [neonixie-l] Re: Q: Active full-wave rectifiers

['jf...@my-deja.com' via neonixie-l]

If all you want is to get 5Vdc rom the mains, a USB charger seems like a 
very attractive option.  They are usually less than US$5 and occupy about 
1cu in (plus the power plug).  My initial concern would be safety 
isolation, but some of these will surely be UL listed or CE qualified.

However, if you are doing an engineering laboratory exercise requiring 
using a 6.3vac source then this is almost interesting.  It should be 
possible to build a buck-boost regulator that will tolerate a very wide 
range of unregulated inputs.

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[neonixie-l] Re: Q: Active full-wave rectifiers

['jf...@my-deja.com' via neonixie-l]

If I had to use the 6V transformer, I would make a voltage doubler.  

Then I would use the switching mode regulator in a USB car charger adapter 
to produce the regulated 5V.   My Dollar Tree carries them.  Sometimes, 
Fry's has these for under US$1.  Or you can probably find one at your 
favorite truck stop for US$9.95.  I would physically hack iawy the case to 
get at the electronic innards. 

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[neonixie-l] Re: The case of the singing nixie tube

['jf...@my-deja.com' via neonixie-l]

Does it also produce RFI on the AM band?  My 6-digit B-7971 clock sings and 
produces RFI at the MUX rate

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[neonixie-l] Re: Sale a big VFD tubes ILC1-1/8L

['jf...@my-deja.com' via neonixie-l]

I don't know about these specific devices, but I have a commercial 
(Lloyd's) clock radio with VFD digits, and it has been running continuously 
for at least 30 years (maybe 40).  YMMV.

On Thursday, December 20, 2018 at 10:19:17 PM UTC-8, gregebert wrote:
>
> Has anyone here built a device with these ? I couldn't resist the $10 USD 
> price for a display that's almost 100mm tall.
> I'm curious about their longevity (or lack thereof)
>

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[neonixie-l] Re: dekatron computing [and other stuff]

['jf...@my-deja.com' via neonixie-l]

 

I made the pilgrimage to Bletchley Park.  It may have been because it was 
Remembrance Day, but it seemed to emphasize the war memorial aspects with 
an acknowledgment to the origins of electronic computing.

 

I did not see the Disneyland aspects, and there were no actors in period 
clothes speaking English from the mid-20th century.  There were helpful and 
friendly people who answered visitors’ questions.  They also had videos and 
mockups of the Colossus.

 

I also went to the National Museum of Computing, also on the grounds of 
Bletchley Park, but with a separate admission.  The collection is 
extensive, but the display was constrained by the pre-existing layout of 
the building.  Also, I do not remember seeing any non-electronic 
calculation devices like Napier’s bones, abacuses, slide rules, etc.

 

They had a number of early electronic calculating devices including Bombe, 
EDSAC, and Colossus (although this may have been a reproduction instead of 
a restoration).  

 

Of particular interest to this group is the Harwell WITCH, consisting of 
relays and dekatrons.  It seemed to be running when I was there (flashing 
lights and clunking relays), but I did not talk to anyone with an intimate 
familiarity of the machine.  The point is that the dekatrons you guys 
donated went to a good home.  It felt like a volunteer operation manned by 
people interested in the technical aspects of the restoration, and 
relatively little interest in the administration of the project.  This is 
not an excuse, but it may explain why they were remiss in expressing their 
gratitude.  My peripheral concern is that they may be consuming the useful 
life of the dekatrons and replacements may become more difficult to acquire.

 

Overall, I found this to be a worthwhile day trip from London.

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Re: [neonixie-l] Re: "Keep Alive" Circuit

['jf...@my-deja.com' via neonixie-l]

The MM5369 produces a 60Hz signal from a 3.579545 MHz crystal, not 1 pps.  
I vaguely  recall that there was a version that produced 50 Hz from a PAL 
crystal.

The MM5369 can be found on ebay for about US$1 in medium quantities.  These 
may be Chinese counterfeits, but it is not a technologically demanding 
application, so it should work fine.

If you cannot find an old NTSC TV to cannibalize, the crystals are 
available new for about US$1 from the usual hobbyist surplus stores ( e.g., 
https://anchor-electronics.com/price-list.pdf ).

One additional thought is that the backup battery should physically mounted 
in a low location , preferably in a container that keeps it separated from 
the electronic circuitry.  I once made the mistake of mounting it in the 
case above the circuit board, and the electrolyte leakage damaged some 
components (including some IC chips).

>

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[neonixie-l] Re: "Keep Alive" Circuit

['jf...@my-deja.com' via neonixie-l]

On Wednesday, September 5, 2018 at 7:50:55 AM UTC-7, Jim KO5V wrote:
>... My guess is that this is more than just adding in a circuit with a 
battery - a frequency source may also be needed. 

If you want an integrated solution instead of adding an outboard UPS, 
consider this:

All my ideas are stolen from the Cal-Tex CT7001 clock/calendar chip.  They 
recommend using a battery to keep the logic alive. 

Their clever idea was to use the MUX oscillator to help keep time when the 
mains were out.  You could emulate this idea by building a 60 Hz source 
that was phase-locked to the line frequency (and very close to 60 Hz 
free-running), possibly based on a NE565 or NE555.  This could also improve 
the time keeping in normal operation, since the clock would be more immune 
to the noise spikes on the power line (my clocks based on MM5531x chips, 
TTL logic, and CMOS logic all ran slightly fast and I blame that on 
counting excess noise pulses).  

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Re: [neonixie-l] Re: How many people would be interested in 3 digit Nixie car gauges?

['jf...@my-deja.com' via neonixie-l]

On Thursday, August 30, 2018 at 2:14:01 PM UTC-7, iavine wrote:
>
> One problem other people have had with such projects is mechanical 
> vibration causing cathodes to short out 
>
> IanV
>

If you want to review an earlier discussion, see 

https://groups.google.com/forum/#!msg/neonixie-l/Vw1dwR_CMDQ/eCtmEBUsLYMJ;context-place=topic/neonixie-l/TOQxmbVwXek

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Re: [neonixie-l] Re: Possibly offtopic - Vintage MV1 LEDs for sale

['jf...@my-deja.com' via neonixie-l]

On Friday, April 13, 2018 at 8:27:35 AM UTC-7, Jens Boos wrote:
>
> Is there a datasheet for this LED? I am really interested in the current 
> draw. (The voltage is fixed, more or less, by the wavelength. So the 
> current will tell us something about the efficiency.) Jens
>
Google "GaAs LED  efficiency".  According to 
https://www.ele.uva.es/~pedro/optoele/LEDs/Bright_LEDs.pdf , before 1973 
the efficiency was  under 1% or under 0.2%, depending on the chemistry.

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Re: [neonixie-l] Possibly offtopic - Vintage MV1 LEDs for sale

['jf...@my-deja.com' via neonixie-l]

Early LEDs were not bright enough to be seen in broad daylight.  That was 
one of the advantages of numitrons.

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[neonixie-l] Re: 26 In18 Tubes

['jf...@my-deja.com' via neonixie-l]

On Monday, April 2, 2018 at 11:04:16 AM UTC-7, Jeff Aylesworth wrote:
> The lowest hanging fruit seems to be the plasma ball proximity test.
> Jeff
Along the same lines, you could use your toy Tesla coil or van de Graaf 
generator...

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[neonixie-l] Re: 26 In18 Tubes

['jf...@my-deja.com' via neonixie-l]

You don't need a "Nixie tester".  All you need is current-limited high 
voltage.  In the US, a 100K resistor in series with 120-150 Vac (use an 
isolation transformer; do not connect directly to the mains!) should light 
one or two digits at a time.

Are you sure they are new?  Can yo see any longitudinal scratches on the 
pins?  This would be evidence of insertion into sockets.

To my eyes, it looks like the pins are not true.  That could be evidence of 
stress that could have broken the glass-to-metal seal and allowed the neon 
t leak out.  The conventional wisdom is that sockets should have floating 
pins that do not stress the pins (socket pins not rigidly soldered to the 
pc board).

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Re: [neonixie-l] Re: Numitron clock driving question

['jf...@my-deja.com' via neonixie-l]

On Wednesday, February 21, 2018 at 7:43:27 AM UTC-8, nixiebunny wrote:
>
> The inrush current performs the important job of heating up the filament 
> so that it will glow. Don't expect an LED driver to work well. Experiment 
> with some low ohmage series resistors first.t 
> .
>
It has been a long time and, technically, this applies to RCA numitrons and 
not necessarily the Russian clones.  ISTR that they were designed to be 
directly driven by a 7447 and a 5V power supply without needing any series 
current-limiting resistors.  One of the advertised advantages was that they 
could be read in direct sunlight, which was not true for the early LEDs.

I also recall that GE claimed that the life of an incandescent lamp was 
inversely proportional to the twelfth power of the applied voltage.  If you 
can extrapolate from household lighting running on 110VAC, you can expect 
the life of your numitrons to be increased by about 4X by adding a series 
diode to drop the applied voltage by about  0.6V.

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Re: [neonixie-l] Re: Clock Three Jr. - What Amp for AC adapter?

['jf...@my-deja.com' via neonixie-l]

On Saturday, December 2, 2017 at 2:18:41 PM UTC-8, Dman777 wrote:
>
>  Plexi glass is really hard to clean and it scratches easy. Mine has 
> hundreds of tiny scratches on it from the people that assembled it and 
> wiped it down. It's not a big deal from far away, but if I manage to keep 
> the clock working 10 years from now the front def. would be worse off. 
>
Have you tried fire polishing it?   It worked for me.  For more info, just 
Google.  As usual, first practice on a piece of scrap plexiglas.

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[neonixie-l] Re: New electronics magazine....

['jf...@my-deja.com' via neonixie-l]

It looks interesting, but it costs AUD200.95 for a 12-month subscription, 
or more than US$150 at current exchange rates.

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[neonixie-l] Sand clock

['jf...@my-deja.com' via neonixie-l]

Not nixies, but interesting

https://www.elektor.com/sandclock-160065-71?utm_source=Elektor+United+States+%28English%29_campaign=4c9b63a752-19april2016_Siglent_NL_4_15_2016_medium=email_term=0_8b7374950c-4c9b63a752-234906893_cid=4c9b63a752_eid=747f1b4e42

"This supercool gadget built around an Arduino Uno writes the time into a 
layer of sand. After an adjustable time the sand is flattened out by two 
vibration motors and everything begins all over again."

Disclaimer:  I am a subscriber to Elektor, but have no other relationship 
to the seller.

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[neonixie-l] Steampunk Nixie tube clock: The electronics are up and running

['jf...@my-deja.com' via neonixie-l]

This guy made his own tubes!

http://www.embedded.com/electronics-blogs/max-unleashed-and-unfettered/4442670/Steampunk-Nixie-tube-clock--The-electronics-are-up-and-running?_mc=NL_EMB_EDT_EMB_weekly_20160914=NL_EMB_EDT_EMB_weekly_20160914=8f78514f459844c597aeb148fa6efaf6=0c13ac7c5ee24c8695f127ddf3e734b2=33866=1=29601

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Re: [neonixie-l] Re: b7971 segment current

['jf...@my-deja.com' via neonixie-l]

I will believe it when I see it.

On Tuesday, August 30, 2016 at 5:20:08 PM UTC-7, A.J. Franzman wrote:
>
> If you sputter enough metal onto any insulator, you can make it conduct.
>
> On Tuesday, August 30, 2016 at 1:28:06 PM UTC-7, j@my-deja.com wrote:
>>
>>  I think this is improbable.  On the one tube that I dissected*, the back 
>> substrate is an insulating white ceramic with an insulating  black ceramic 
>> overcoat.
>>
>

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Re: [neonixie-l] Re: b7971 segment current

['jf...@my-deja.com' via neonixie-l]

I would believe it was NOS if it was accompanied by a pristine box, the 
lettering on the tube was all sharp and crisp, and the pins were all 
straight (with no tool marks from straightening) and unscratched (or maybe 
one scratch from burn-in).


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Re: [neonixie-l] Re: b7971 segment current

['jf...@my-deja.com' via neonixie-l]

On Monday, August 29, 2016 at 9:31:39 PM UTC-7, A.J. Franzman wrote:
>
> ... They might be shorted to the back substrate and possibly even each 
> other via the substrate...
>
 I think this is improbable.  On the one tube that I dissected*, the back 
substrate is an insulating white ceramic with an insulating  black ceramic 
overcoat.

BTW, this is one of the reasons I think there are no NOS tubes.  It would 
be a lot of unnecessary additional work to deliberately put the shadow 
pattern into the black ceramic overcoat.

* My one catastrophic failure because the glass envelope could not 
withstand being struck by the floor.

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Re: [neonixie-l] Re: b7971 segment current

['jf...@my-deja.com' via neonixie-l]

On Saturday, August 27, 2016 at 1:38:28 PM UTC-7, rmp wrote:
>
> To the folks who are still running the "Giant Nixie Clock". From the early 
> 1970's:
> ... as I recall it treated the tubes as 7-segment devices...Am I correct? 

 Yes.  It was based on the MM5314 from National Semiconductor.   

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[neonixie-l] Re: b7971 segment current

['jf...@my-deja.com' via neonixie-l]

On Tuesday, August 23, 2016 at 10:25:09 PM UTC-7, gregebert wrote:
>
> 40 *years* ? How many hours per day are you running your tubes ?
>
Mine has been running 24x7x365.25, with brief exceptions for things like 
moving to a new home, power outages due to earthquakes (California!) and 
weather, etc.  The other two were gifts, but I have not needed to replace 
any tubes in those (and I get to check on them occasionally).   It was a 
basic design typical of the 1970s: linear power supply and a CT7001 clock 
chip.  It did not have the additional circuitry that would have been 
required to dim the bulbs or turn them off.  At $1/tube, there was no 
incentive to complicate the circuitry in an attempt to "extend" the life of 
the tubes, and as the experiment has demonstrated, it would have been a 
waste of time and effort.

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[neonixie-l] Re: Constant current regulator for Nixies

['jf...@my-deja.com' via neonixie-l]

On Saturday, August 13, 2016 at 5:45:22 PM UTC-7, ZY wrote:
>
> ...maybe some regulation circuitry would be worth it in the long run?
>
> If you do this, you might want to modulate the current proportional to 
illuminated length of each character, so an 8 would draw more current than 
a 0 and much more than a 1.  If these dimensions are not already in the 
spec sheet, you could measure them yourself.
 

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[neonixie-l] Re: b7971 segment current

['jf...@my-deja.com' via neonixie-l]

I did nothing heroic.  I used the cheapest transistors I could find 
(PolyPaks, John Meshna, etc.) and carbon comp resistors.  I used the 
resistor values in the old "73 Magazine" article "Build a Giant Nixie 
Clock" from the mid-1970s, and increased the HV power supply voltage until 
it was "bright enough" (about 175V on my old Lafayette VOM).   The resistor 
values may have changed with time, but I think they were initially 1-2ma 
per segment.

I built three clocks with a total of 18 tubes.  So far, after 40+ years, 
there have been zero tube failures.  The $20 I spent on spare tubes (at $1 
each) has been a waste of money.

The tubes were multiplexed.  I found that the biggest problem is that the 
tubes sing at the mux rate, and the volume increased with the drive 
current. (Someone once suggested that the sound was coming from the power 
supply, but this was way back in the old days and I only built linear power 
supplies operating at the line frequency of 60 cps.) 

On Friday, August 19, 2016 at 9:00:55 AM UTC-7, gregebert wrote:
>
> According to the b7971 datasheet, the maximum allowable current is 21mA. 
> Yet when you add-up the currents for each cathode to produce the  '8' or 
> '*' characters, they add up to 40mA, which is way over the spec limit.
>
> For those of you who design their clocks, did you scale-back all segment 
> currents so they never exceed 21mA ?
>
> I'll probably current-limit each cathode individually, and put another 
> current-limit on the anode. Even though that adds up to a lot of 
> transistors for a direct-drive clock, these tubes are getting pretty scarce 
> and expensive so I'm not taking any chances.
>
>
>
>

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[neonixie-l] Re: OT: US Customs Service - Delays

['jf...@my-deja.com' via neonixie-l]

On Wednesday, March 30, 2016 at 12:10:00 PM UTC-7, jf...@my-deja.com wrote:
>
> I am not sure who is to blame, but after almost two months, I am still 
> waiting for some 13-pin dekatron sockets being sent from Russia.  
>
They finally arrived after 12 weeks.  Based on the tracking information, it 
took about 11 weeks  to get to New Jersey, and another week for the USPS to 
get it to California.  The package was marked "Air Mail" and covered with 
stamps, but it looks like both countries treated it as surface mail.

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[neonixie-l] Re: OT: US Customs Service - Delays

['jf...@my-deja.com' via neonixie-l]

I am not sure who is to blame, but after almost two months, I am still 
waiting for some 13-pin dekatron sockets being sent from Russia.  

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[neonixie-l] Re: Off topic, but it has an orange display.. Heathkit ID-1590 anemometer

['jf...@my-deja.com' via neonixie-l]

Modern LEDs may be "better", but back in the old days, LEDs were no 
characterized for reverse operation and were pretty poor rectifiers (I 
forget whether it was leakage or low and unpredictable breakdown voltage, 
or both).  I would keep the series Si diodes.
 
There was a lot of discussion about multiplexng back in the early days of 
LED 7-segemnt displays.  In those days, pulsing was preferred since the 
efficiency went up with the instantaneous drive current so I think I is OK 
to run the LEDs on unfiltered pulsing dc. 

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[neonixie-l] Re: Good B7971s?

['jf...@my-deja.com' via neonixie-l]

Back in the early 1970s, the cheap ones (~$1) all came with sockets with 
cutooff wires.  For about double the price, you could get the bracket with 
the HV driver transistors.  Clearly, these were used surplus from the 
NYSE.  It seems that they stayed cheap until the Nixie nostalgia hit the 
hobbyists in the 1990s.  I do not remember anyone since the 1970s claiming 
to have seen one come out of a sealed box.
 
On my tube that got broken, the substrate is a white ceramic, and it looks 
like there is a flat black coating of some kind.  In a brand new tube, I 
would expect either no shadowing (apply coasting before adding cathode 
wires) or much more crisply defined shadows.  To me, the wide and diffuse 
shadowing looks like erosion.  I think it would be kinda hard to 
deliberately manufacture in these shadows, and unless they are functional, 
it would not be worth the effort.

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Re: [neonixie-l] Bad B7971's

['jf...@my-deja.com' via neonixie-l]

On Monday, March 7, 2016 at 2:06:42 PM UTC-8, Jeff Walton wrote:
>
> I have a clock that uses Raytheon CK8754 tubes that has 35 years 
> continuous use with no tube issues.  That's over 300,000 hours.  I hope 
> that the B7971's last as long.  I'll probably be gone by then.. 
>
> *Jeff *
>
I think I last posted about this more than five years ago.  A little more 
than 40 yers ago, I built three 6-digit clocks with B7971s.  They have been 
running 24/7/365.25, and there have been no tube failures, yet (one dead 
power transformer, some electrolytics, and one clock chip).  The tubes were 
cheap at the time (I think they were from John Meshna), so nothing was done 
in the design to extend their lifetime.  I also stocked up on spare tubes, 
and based on the current prices, I plan to use them to fund my retirement. 

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