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
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
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
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,
>
--
You
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
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
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
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!
>
>
>
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
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
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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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
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
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
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
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
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
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
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
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
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
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.
--
You received
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
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
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
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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So the pictures I intended did not et posted on the Google Groups version.
The first image is the "fast" picture from
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
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...
--
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
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
...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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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
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
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
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
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
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
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 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,
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,
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
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 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
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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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
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
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
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
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
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
Early LEDs were not bright enough to be seen in broad daylight. That was
one of the advantages of numitrons.
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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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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
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
>
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
>
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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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
This guy made his own tubes!
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
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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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
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.
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,
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
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
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,
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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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
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
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
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