[neonixie-l] Re: Driving NEO-5000 and SP-352 displays

[gregebert]

I built a wristwatch with the SP-151 display in direct-drive mode, using 
335uA per segment. I've never seen any mention of recommended current for 
multiplexed operation, and  running it too high will damage the display. So 
on that basis I stayed with direct-drive; doing that I dodged all of the 
nuances of multiplexing (ghosting, keep-alive, blanking interval, bias, 
audible noise, flickering, etc). Using a 4-layer PCB, I was able to tuck 
all of the segment-driver driver transistors (dual NPNs) and the 3 
shift-registers in about the same footprint of the display itself, so the 
penalty of extra components for direct-drive is low.

Regarding the NEO-5000, I suggest you plot the I-V data for the segments to 
help you get the current set right.


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[neonixie-l] Driving NEO-5000 and SP-352 displays

[Robert Armstrong]

  I have six NEO-5000 and two SP-352 displays that I'm planning to use to 
build a clock.  I'll use four of the NEO-5000s as hours and minutes, and 
one of the SP-352s for the seconds.  It'll all be driven by a 
microprocessor, maybe an ESP8266.  The micro part is easy but I don't have 
a lot of experience with these Panaplex type displays and I don't want to 
damage them.  BTW, I'll keep the extra displays as spares just in case one 
in the clock fails...

  My plan is to multiplex the two SP-352 digits using a single DM8880 as 
the cathode driver and two TLP627s as the high side switch.  I have a 
couple of the DM8880s; they have a built in constant current sink so I 
don't have to mess with separate cathode resistors, and I'm fine with the 
decimal only font for the seconds display.

  The four NEO-5000s will be multiplexed using a SN75468 with the outputs 
clamped to 90V as the cathode driver.  The high side driver will be four 
more TLP627s.  Since the 75468 doesn't have a constant current sink I'll 
use seven discrete resistors to limit the segment current.  This 
arrangement will allow me to generate any pattern I want on the NEO-5000 
segments.

  Three 74HC595 shift registers should provide enough output bits to 
control all the displays and only need three I/O bits on the ESP8266.  All 
told, this is a pretty simple, low part/chip count design.

  Questions - is this a reasonable plan?  I found a datasheet for the 
SP-35x parts and it recommends 350uA per segment.  Is it reasonable to 
double this for a 50% duty cycle?  Also, I'm a little puzzled about what 
I'm supposed to do with the "Keep Alive" cathodes on these things.  How 
should they be connected?

  The NEO-5000s are a bigger problem.  The only data I could find on them 
was on tubeclockdb, and it recommends an average cathode current of 0.6 to 
0.9mA.  It also recommends a duty cycle of 1/16th, segment cathode 
resistors of 4K and an anode supply of 220V.  Oh, and an ON time of not 
more than 500uS.  is 4K ohms really correct, even for a 1/16 duty cycle?  
That seems way too low based on my math.  

  Anyway, as long as I keep the average cathode current to, say, 0.75mA 
does the duty cycle really matter?  With a 4 digit display I'd nominally 
have a 25% duty cycle.  I could insert dead time to artificially limit it 
to 1/16, but it seems like that'd waste a lot of brightness.  I guess the 
question is, is it better to run them at very high current for very short 
pulses, or much lower current for longer pulses?

  Thanks for the advice - I want these guys to last a long time!

Bob Armstrong

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Re: [neonixie-l] Re: I'm Back: ZM1022 and B-7971

[Bill Notfaded]

I have never had a failure with a working B-7971 tube.  They are, if
working, rock solid.  Unless you start with a messed up tube I would say
they are some of the most stable neon tubes ever made.  Big, bad@55, rock
solid tubes.  I'm sure cutting off pins or a rare overlapped cathode might
be an issue.  I'd say if you had an overlapped cathode issue then
definitely try the taped broomstick method and try to knock it loose
because these tubes run and run and run as long as they don't have physical
defects inside.  Ironically they are some is the best tubes ever made as
far as I'm concerned.  They are bright and just work great.  Yeah...
they're expensive these days but dang they're awesome!!!  I'm sure Michail
and Michael will both concur... B-7971 tubes are some of the most awesome
Nixie tubes ever made period.  They're really priceless now because no one
makes them anymore.  Even the new age Nixie tube manufacturers aren't even
trying alphanumerics.  These are it... and they're awesome!   Still running
strong... Big... Beautiful!

Bill

On Sat, Oct 12, 2019, 10:51 AM Michail Wilson  wrote:

> Robert, you
>
>
>
> I have come across a lot of tubes with this issue (not the cut off leg).
>
> Although I have broken more than my share of tubes by dropping them, I
> have never broke a tube with a short.
>
>
>
> I have over the years been able to smack the short out of them.  I believe
> you will find it is easier than you think it might be.  Of course you will
> see dollar signs flash in front of you each time you smack it.
>
>
>
> Trying to look closely at your short, my suggestion would be to put the
> tube in a socket and smack the tube in a downward fashion on a table.  The
> socket being used to protect the pins and the nipple.  Also try smacking
> the face of the tube into your hand.
>
>
>
> Michail Wilson
>
> 206-920-6312
>
>
>
> *From:* neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] *On
> Behalf Of *Robert G. Schaffrath
> *Sent:* Saturday, October 12, 2019 10:17 AM
> *To:* neonixie-l
> *Subject:* Re: [neonixie-l] Re: I'm Back: ZM1022 and B-7971
>
>
>
> It took some digging around to find it, but I did locate the Ultronics
> B-7971 with the shorted segments. This is a closeup picture of the short:
>
>
>
> [image: B-7971 Shorted.jpg]
>
>
>
> Then for some reason around 30 years ago, I decided to cut the #17 pin off
> which is connected to the #13 slanted segment that is shorted. Not sure why
> I did that or what I was thinking back then. If I can resurrect the tube,
> it would not be that big a problem to attach an extension to the remaining
> stub and make #13 usable again:
>
>
>
> [image: B-7971 Cut Pin.jpg]
>
>
>
> Finally, my 40 year old 6 tube clock in operation. I had not powered it up
> in a while. Still works! Mind boggling to think the tubes in this clock
> could be worth close to USD$900 now (It is covered in plastic due to the
> dust issues. I got tired of cleaning off the tubes when I wasn't even using
> it):
>
>
>
> [image: B7971 Clock.jpg]
>
>
>
>
>
>
>
>
>
>
>
>
>
> On Wednesday, October 9, 2019 at 11:29:18 AM UTC-4, Robert G. Schaffrath
> wrote:
>
> That link is not working but a search of the forum turned this thread up:
>
>
>
>
> https://groups.google.com/forum/#!searchin/neonixie-l/shorted$20segment|sort:date/neonixie-l/w4YmXnY9dgE/8o-AsZZyBQAJ
>
>
>
> I assume that is the thread you were referring to. I'll have to give it a
> try. If the tube breaks then so be it. About all it is good for is making
> either an "A" (8 with bottom off) or "P" for an AM/PM indicator. 20+ years
> ago or so I stupidly cut off the pin for the #13 segment because it was
> shorted but it could be repaired and used again. Especially considering the
> value of the tubes it would be a minor inconvenience.
>
>
>
> I'll have to dig the tube out this weekend and give the repair process a
> shot.
>
> On Tuesday, October 8, 2019 at 10:47:08 AM UTC-4, Jeff Walton wrote:
>
> Check out this thread for repairing the shorted segments:
> https://groups.google.com/forum/m/#!searchin/neonixie-l/Shorted$20segment$20b7971/neonixie-l/w4YmXnY9dgE
>
>
>
>
>
>
>
> *Jeff *
>
>
>
>  Original message 
>
> From: "Robert G. Schaffrath" 
>
> Date: 10/8/19 8:47 AM (GMT-06:00)
>
> To: neonixie-l 
>
> Subject: Re: [neonixie-l] Re: I'm Back: ZM1022 and B-7971
>
>
>
> With me it is the only B-7971 tube I have like that. It came from the
> first Ultronics board I ever purchased in the late 1970's. It came from
> Poly Paks IIRC. It was actually a bad deal for me. Apparently the board had
> been serviced which explains the genuine Burroughs tube that was on the
> board. The other tube is Ultronics (which I still have) and is defective.
> The #4 and #13 segments touch each other causing both to light when either
> is energized. The circuit board had jumpers soldered onto it and
> handwritten in fine tipped magic marker it said "modified for dummy 0". My
> parents joked at my expense that it was modified for the 

RE: [neonixie-l] Re: I'm Back: ZM1022 and B-7971

[Michail Wilson]

Robert,

 

I have come across a lot of tubes with this issue (not the cut off leg).

Although I have broken more than my share of tubes by dropping them, I have 
never broke a tube with a short.

 

I have over the years been able to smack the short out of them.  I believe you 
will find it is easier than you think it might be.  Of course you will see 
dollar signs flash in front of you each time you smack it.

 

Trying to look closely at your short, my suggestion would be to put the tube in 
a socket and smack the tube in a downward fashion on a table.  The socket being 
used to protect the pins and the nipple.  Also try smacking the face of the 
tube into your hand.

 

Michail Wilson

206-920-6312

 

From: neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On 
Behalf Of Robert G. Schaffrath
Sent: Saturday, October 12, 2019 10:17 AM
To: neonixie-l
Subject: Re: [neonixie-l] Re: I'm Back: ZM1022 and B-7971

 

It took some digging around to find it, but I did locate the Ultronics B-7971 
with the shorted segments. This is a closeup picture of the short:

 

B-7971 Shorted.jpg

 

Then for some reason around 30 years ago, I decided to cut the #17 pin off 
which is connected to the #13 slanted segment that is shorted. Not sure why I 
did that or what I was thinking back then. If I can resurrect the tube, it 
would not be that big a problem to attach an extension to the remaining stub 
and make #13 usable again:

 

B-7971 Cut Pin.jpg

 

Finally, my 40 year old 6 tube clock in operation. I had not powered it up in a 
while. Still works! Mind boggling to think the tubes in this clock could be 
worth close to USD$900 now (It is covered in plastic due to the dust issues. I 
got tired of cleaning off the tubes when I wasn't even using it):

 

B7971 Clock.jpg

 

 

 

 

 



On Wednesday, October 9, 2019 at 11:29:18 AM UTC-4, Robert G. Schaffrath wrote:

That link is not working but a search of the forum turned this thread up:

 

https://groups.google.com/forum/#!searchin/neonixie-l/shorted$20segment|sort:date/neonixie-l/w4YmXnY9dgE/8o-AsZZyBQAJ
 

 

 

I assume that is the thread you were referring to. I'll have to give it a try. 
If the tube breaks then so be it. About all it is good for is making either an 
"A" (8 with bottom off) or "P" for an AM/PM indicator. 20+ years ago or so I 
stupidly cut off the pin for the #13 segment because it was shorted but it 
could be repaired and used again. Especially considering the value of the tubes 
it would be a minor inconvenience.

 

I'll have to dig the tube out this weekend and give the repair process a shot.

On Tuesday, October 8, 2019 at 10:47:08 AM UTC-4, Jeff Walton wrote:

Check out this thread for repairing the shorted segments:  
https://groups.google.com/forum/m/#!searchin/neonixie-l/Shorted$20segment$20b7971/neonixie-l/w4YmXnY9dgE

 

 

 

Jeff 

 

 Original message 

From: "Robert G. Schaffrath"  

Date: 10/8/19 8:47 AM (GMT-06:00) 

To: neonixie-l  

Subject: Re: [neonixie-l] Re: I'm Back: ZM1022 and B-7971 

 

With me it is the only B-7971 tube I have like that. It came from the first 
Ultronics board I ever purchased in the late 1970's. It came from Poly Paks 
IIRC. It was actually a bad deal for me. Apparently the board had been serviced 
which explains the genuine Burroughs tube that was on the board. The other tube 
is Ultronics (which I still have) and is defective. The #4 and #13 segments 
touch each other causing both to light when either is energized. The circuit 
board had jumpers soldered onto it and handwritten in fine tipped magic marker 
it said "modified for dummy 0". My parents joked at my expense that it was 
modified for the dummy (me). Why the Ultronic service center did not replace 
the defective tube rather than go through the effort of modifying the board 
escapes me. Especially since they replaced what I assume had been an Ultronic 
tube in the other socket. I could have had two Burroughs tubes with posts.

 

When I decided I wanted to get three more boards, I bought them from Meshna due 
to my bad experience with the other vendor. After I had those boards, I decided 
to splurge on the 6 NOS B-7971's. I still have one Ultronics board left that 
has the sockets still installed but no tubes. I used the other three for 
sockets and HV transistors to build my MM5311 clock.

On Monday, October 7, 2019 at 7:48:07 PM UTC-4, Bill Notfaded wrote:

They made less of the antenna variety from what I've seen.  Most of mine don't 
have them.

Bill

I also have I believe a 1.06 version of that clock that runs off the mains.  
Mines running z566m red tubes.

Bill

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To view this 

[neonixie-l] Re: NL7037 clock

[MichaelB]

Gorgeous Paul!! Reminds of a sexy little single-ended power amp! And the 
meters are a perfect fit! Congrats!

On Wednesday, October 2, 2019 at 10:27:47 AM UTC-7, Paul Andrews wrote:
>
> Finally completed this NL7037 clock/space heater. Vacuum-tube power 
> supply, ESP32 processor for networking, clock, sounds etc.
>
> I'll do a write-up on the odyssey that got me here in a few weeks. It has 
> been fun.
>
> [image: IMG_4132.JPG]
>
>
> Meters for the HV and nixie tube current - That's DC voltage, not AC
>
>
> [image: IMG_4136.JPG]
>
>
> Back view, with the teeny tiny WiFi antenna. The knob controls the HV 
> level.
>
>
> [image: IMG_4137.JPG]
>
>
>
>
>

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[neonixie-l] Re: Nixie LAB

[LInk Cheng]

Aww.. I hope you can ship it to my Country soon..   do keep me updated !

On Monday, October 7, 2019 at 5:56:37 AM UTC+8, Marcin Saj wrote:
>
> I just finished my new project - Nixie LAB.
> Modular architecture, you can control any 2/4/6/8/10 nixie tubes, 
> compatible with 25 different sockets for over a hundred different nixie 
> tubes. Current efficiency up to 200mA at 170V! Can be controlled by: 
> Arduino (all boards) Raspberry Pi (all), Particle Photon / Argon / Xenon, 
> Wemos D1 Mini, D1 Mini Pro, D32, D32 Pro. Dedicated housings. 
> Details: http://bit.ly/nixie-lab 
> 
>
> [image: nixie-lab-8-5-nixie-tubes-2.jpg]
>
> [image: 2 x rz568 2 x b7971.jpg]
>
>
>
>

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