RE: [neonixie-l] CD27 Loose Base

[theoldphart2]

Have used regular super glue on several radio tubes with loose bases. The glue 
soaks in between the base and glass, and never failed since.

 

Bill v.

 

From: neonixie-l@googlegroups.com  On Behalf Of 
alex nolan
Sent: Monday, June 17, 2024 8:57 PM
To: neonixie-l 
Subject: [neonixie-l] CD27 Loose Base

 

I recently found a few CD27 that work, but the glass tube seems to be loose in 
the black plastic base that contains the pins. Does anyone have any tips for 
how to secure the two pieces together? I don't want to risk damaging the tube 
with something that would generate heat or other stress on the glass.

Would some sort of epoxy work? Or perhaps a silicone based glue?

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RE: [neonixie-l] Test

[theoldphart2]

Yup, it works!

 



 

Bill v.

 

From: 'neonixie-l' via neonixie-l  
Sent: Tuesday, September 19, 2023 12:59 PM
To: neonixie-l 
Subject: [neonixie-l] Test

 

Test 

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RE: [neonixie-l] Need advice on a new scope...

[theoldphart2]

I have in my basement an unbuilt Heathkit 5 MHz scope! (Flea market find!) 
Interested?  (I was thinking of using it to build a scope clock, but the thing 
will be huge)

 

If you are not used to a digital scope, they do have a learning curve although 
the number of on-screen measurements and hold functions are awesome. Yet I 
still often go back to one of my analog scopes, especially when working with 
low frequency stuff. Whatever you do, try to fix the old scope, and keep it 
handy.

 

I have as my main scope a 300MHz Tektronix TDS3250 scope, now 13 years old. It 
died recently. Turns out is has a Dallas (Clock / ram) chip with integrated 
battery. The battery died, the Dallas chip is unobtanium, and is very 
efficiently soldered into the board. No parts to be had. I found a chip in 
China, but since it is old stock, I have no idea how long that one will last. 
(I got the old chip out with my Hakko desoldering rig, and put in a socket)

 

There is a lot to be said for the old scopes!

 

Bill v.

 

From: neonixie-l@googlegroups.com  On Behalf Of 
martin martin
Sent: Thursday, April 20, 2023 11:45 PM
To: neonixie-l 
Subject: [neonixie-l] Need advice on a new scope...

 

My Tek 2236 is nearly 30 moons old and no longer stays on for more than a few 
minutes.  I am sure it's fixable, but on the other hand maybe time for a new 
digital!

 

What do you guys suggest for general use and of course clock fixing?

 

 

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RE: [neonixie-l] Are numitron illegal in UK ???

[theoldphart2]

Customs people are dumb people. They hear one story, and simplify it to apply 
to everything. Take for instance the 866 rectifier tube popular in ham 
transmitters. It is a mercury rectifier, and it actually contains so much 
mercury that it visibly beads on the glass when cold. So, it is confirmed, 
tubes contain mercury. Are there tubes without mercury? Who knows, but I am a 
diligent government employee, so nothing dangerous gets past me! All tubes are 
now condemned, and the world is now safe thanks to me. Don’t like it? File a 
complaint!

 

Wat is even worse, they don’t seem to have a universally used specification 
book, or if indeed one exists, not all of them seem to have one or where to 
find it. I usually mark tubes as old radio tubes, and (knock on wood….) have 
not had a problem to date.

 

Sad, but true.

 

Bill v.

 

From: neonixie-l@googlegroups.com  On Behalf Of 
Nick Andrews
Sent: Thursday, April 13, 2023 6:54 PM
To: neonixie-l@googlegroups.com
Subject: Re: [neonixie-l] Are numitron illegal in UK ???

 

So, so dumb.  Likely not enough mercury in the entire history of nixie 
production to be concerned about in one package even!  Like the hysterical 
nonsense of closing down a school because someone broke a fluorescent light 
bulb or one of those insipid coiled compact flo ones, with what, 1/20th of a 
drop of mercury in it, maybe?  People are nuts.

 

On Thu, Apr 13, 2023 at 4:41 PM 'Mike Harrison' via neonixie-l 
mailto:neonixie-l@googlegroups.com> > wrote:

On Thu, 13 Apr 2023 12:57:38 -0700 (PDT), you wrote:

>I tried to buy some IV-16 in a foreign country, far over the channel.
>here is the message I just received from ebay:
>
>Hello Benoit,
>
>The purchase you recently made under the International Delivery Service 
>with  could not be completed.
>
>The object in question has been restricted. This may be due to import or 
>delivery restrictions, or International Delivery Service eligibility 
>requirements. The item will not be sent to you, nor will it be returned to 
>the seller.
>
>Don't worry. You will be fully refunded to the payment method used to 
>purchase the item within 72 hours. We will make two separate refunds: the 
>first for the price of the object and the second for the shipping and 
>import costs. No further action is required on your part.
>
>[image: Sans titre.jpg]

There have been many reported cases of the Ebay shipping program destroying 
nixies and all sorts of
other tubes because they think they contain mercury, and can't be shipped by 
air. 

Never,  ever use Ebay's shipping service for any kind of tube. 

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RE: [neonixie-l] Re: IV-9 numitron lifespan

[theoldphart2]

I just actually realized I was totally wrong with my earlier statement about 
the 4511. If you look at the truth table for this chip you see it has a 
blanking input (pin 4, ^BI). That would make it actually very easy to implement 
software dimming by simply tying all of them to a mpu pin coded with PWM. On my 
own clock this line is already connected to the PIC, so I should be all set to 
implement dimming. Just never thought of using it that way.

 

Amazing where a bit of discussion can lead you!

 

Bill v

 

From: neonixie-l@googlegroups.com  On Behalf Of 
Moses
Sent: Tuesday, March 07, 2023 3:52 PM
To: neonixie-l 
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

I agree with Bill. I like a low part count.. the lower the part count the 
greater the ultimate reliability.

 

The diode drop is a good idea and is what I used along with PWM of high power 
'595 shift registers. I thought about adding a separate DC-DC converter for 
just the tubes.. but that would have been another half dozen parts, and it's 
not 100% efficient, so it would not have saved too much power vs just a plain 
old diode burning off some voltage.

 

I'm going to definitely try to see if I can keep the segments warm in software, 
as everyone agrees the thermal shock of constantly changing segments is not 
ideal.

 

A side by side test of some overdriven tubes, one with warm segments and one 
without, may be an interesting test.

 

Regards,

-Moses

 

On Tuesday, March 7, 2023 at 8:09:08 AM UTC-8 theoldpha...@gmail.com 
  wrote:

Not as easy as that sounds. 

 

If you want to use software (I presume PWM) you cant use a 4511 anymore since 
their greatest advantage (besides the BCD to 7 segment decoding) is its latch 
function. No way to implement any software based dimming. This would require a 
very drastic hardware redesign.

 

Turning the 5V line down would work, but may cause issues with the rest of your 
circuit. A dedicated supply for the 4511’s could work, but depending on the 
final setting, there would be a discord in logic levels between the rest of the 
circuit and the 4511. Nasty, could result in unreliable communications. Level 
shifters could fix that, but wow, we are getting complicated again.

 

The diode is still the best solution in my mind. Working with silicon and 
Schottky diodes you can obtain steps of 0.3V, 0.6V, 0.9V, 1.0V, 1.2V etc. Some 
diodes have slightly different forward voltage drops, so with a bit of 
searching you can obtain a lot of very simple options. Using jumpers of DIP 
switches you can even make it very simple to adjust. Why all the complicated 
solutions?

 

Bill v

 

From: neoni...@googlegroups.com  On Behalf Of 
Batareyka
Sent: Tuesday, March 07, 2023 10:19 AM
To: neonixie-l 
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

There are two ways to solve this problem.


1. Software, but as the author of the topic, there is no software and the 
possibility of editing it (I
  I think so), then method number 2 remains.
2. The 4511 chip has a wide power supply range from 3-16 volts. Put the power 
regulator and turn it up to 4 volts, which will change the output power of the 
lamp filaments accordingly.
Checked more than once.

вторник, 7 марта 2023 г. в 17:02:08 UTC+2, theold...@gmail.com: 

Martin,

 

How did you do that? (schematic)

 

Problem with a pot (or any resistor) is that you would need one for each 
element (7 per tube) since you cannot put one in the common line. Each filament 
draws about 22mA, so depending on the number displayed, the current would be 
anywhere between 44 and 154 mA. This would result in different voltage drops 
depending on the number displayed. It would result in uneven light output. Same 
reason why you could not use a single current regulator pre tube, but one per 
filament would be needed. A voltage regulator (such as a simple diode) does not 
have that disadvantage.

 

Bill v

 

From: neoni...@googlegroups.com  On Behalf Of martin 
martin
Sent: Tuesday, March 07, 2023 9:09 AM
To: neoni...@googlegroups.com
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

How about this clock I built in the early 80s? 5314  clock chip.  I used a 1k 
pot for dimming.  Has been running for  many moons now!

 

 

 

 

~

mcve...@gmail.com

 

 

On Tue, Mar 7, 2023 at 5:55 AM gregebert  wrote:

Under "normal" circumstances, I agree that individual current regulators add a 
lot of circuitry. The reality is that most tubes are no longer manufactured, so 
their numbers are dwindling as the price increases, essentially irreplaceable. 
You wouldn't believe the lengths I went towards protecting NIMO tubes in the 
clock I'm still working on.

 

I've debated about building a numitron clock, and the route I think I will go 
with uses LED 'filaments' that are used in retro light bulbs. Filaments scare 
the heck out of me because they will fail from thermal cycling, but there is no 
alternative for NIMO and VFD displays.

RE: [neonixie-l] Re: IV-9 numitron lifespan

[theoldphart2]

I just actually realized I was totally wrong with my earlier statement about 
the 4511. If you look at the truth table for this chip you see it has a 
blanking input (pin 4, ^BI). That would make it actually very easy to implement 
software dimming by simply tying all of them to a mpu pin coded with PWM. On my 
own clock this line is already connected to the PIC, so I should be all set to 
implement dimming. Just never thought of using it that way.

 

Amazing where a bit of discussion can lead you!

 

Bill v

 

From: neonixie-l@googlegroups.com  On Behalf Of 
Moses
Sent: Tuesday, March 07, 2023 3:52 PM
To: neonixie-l 
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

I agree with Bill. I like a low part count.. the lower the part count the 
greater the ultimate reliability.

 

The diode drop is a good idea and is what I used along with PWM of high power 
'595 shift registers. I thought about adding a separate DC-DC converter for 
just the tubes.. but that would have been another half dozen parts, and it's 
not 100% efficient, so it would not have saved too much power vs just a plain 
old diode burning off some voltage.

 

I'm going to definitely try to see if I can keep the segments warm in software, 
as everyone agrees the thermal shock of constantly changing segments is not 
ideal.

 

A side by side test of some overdriven tubes, one with warm segments and one 
without, may be an interesting test.

 

Regards,

-Moses

 

On Tuesday, March 7, 2023 at 8:09:08 AM UTC-8 theoldpha...@gmail.com 
  wrote:

Not as easy as that sounds. 

 

If you want to use software (I presume PWM) you cant use a 4511 anymore since 
their greatest advantage (besides the BCD to 7 segment decoding) is its latch 
function. No way to implement any software based dimming. This would require a 
very drastic hardware redesign.

 

Turning the 5V line down would work, but may cause issues with the rest of your 
circuit. A dedicated supply for the 4511’s could work, but depending on the 
final setting, there would be a discord in logic levels between the rest of the 
circuit and the 4511. Nasty, could result in unreliable communications. Level 
shifters could fix that, but wow, we are getting complicated again.

 

The diode is still the best solution in my mind. Working with silicon and 
Schottky diodes you can obtain steps of 0.3V, 0.6V, 0.9V, 1.0V, 1.2V etc. Some 
diodes have slightly different forward voltage drops, so with a bit of 
searching you can obtain a lot of very simple options. Using jumpers of DIP 
switches you can even make it very simple to adjust. Why all the complicated 
solutions?

 

Bill v

 

From: neoni...@googlegroups.com  On Behalf Of 
Batareyka
Sent: Tuesday, March 07, 2023 10:19 AM
To: neonixie-l 
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

There are two ways to solve this problem.


1. Software, but as the author of the topic, there is no software and the 
possibility of editing it (I
  I think so), then method number 2 remains.
2. The 4511 chip has a wide power supply range from 3-16 volts. Put the power 
regulator and turn it up to 4 volts, which will change the output power of the 
lamp filaments accordingly.
Checked more than once.

вторник, 7 марта 2023 г. в 17:02:08 UTC+2, theold...@gmail.com: 

Martin,

 

How did you do that? (schematic)

 

Problem with a pot (or any resistor) is that you would need one for each 
element (7 per tube) since you cannot put one in the common line. Each filament 
draws about 22mA, so depending on the number displayed, the current would be 
anywhere between 44 and 154 mA. This would result in different voltage drops 
depending on the number displayed. It would result in uneven light output. Same 
reason why you could not use a single current regulator pre tube, but one per 
filament would be needed. A voltage regulator (such as a simple diode) does not 
have that disadvantage.

 

Bill v

 

From: neoni...@googlegroups.com  On Behalf Of martin 
martin
Sent: Tuesday, March 07, 2023 9:09 AM
To: neoni...@googlegroups.com
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

How about this clock I built in the early 80s? 5314  clock chip.  I used a 1k 
pot for dimming.  Has been running for  many moons now!

 

 

 

 

~

mcve...@gmail.com

 

 

On Tue, Mar 7, 2023 at 5:55 AM gregebert  wrote:

Under "normal" circumstances, I agree that individual current regulators add a 
lot of circuitry. The reality is that most tubes are no longer manufactured, so 
their numbers are dwindling as the price increases, essentially irreplaceable. 
You wouldn't believe the lengths I went towards protecting NIMO tubes in the 
clock I'm still working on.

 

I've debated about building a numitron clock, and the route I think I will go 
with uses LED 'filaments' that are used in retro light bulbs. Filaments scare 
the heck out of me because they will fail from thermal cycling, but there is no 
alternative for NIMO and VFD displays.

RE: [neonixie-l] Re: IV-9 numitron lifespan

[theoldphart2]

If you send me the schematic (with any modifications you may want) and 
preferred board size and shape, I can create board files for you.

 

Bill v

 

From: neonixie-l@googlegroups.com  On Behalf Of 
Nicholas Stock
Sent: Tuesday, March 07, 2023 10:57 AM
To: neonixie-l@googlegroups.com
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

That's the one. Thanks Martin. I've spoken to Richard about getting more PCBs 
made (I have some MM5314's that need a good home) but he can't locate the board 
files. 

 

On Tue, Mar 7, 2023 at 7:54 AM Dekatron42 mailto:martin.forsb...@gmail.com> > wrote:

A quick Googling of MM5314N and Numitron finds this webpage: 
http://www.tuberadios.com/numitron/ with schematic that is said to be 
compliments of Westdave.

 

/Martin

 

On Tuesday, 7 March 2023 at 16:41:24 UTC+1 Nicholas Stock wrote:

If I'm not mistaken, the clock kit that Martin is referring to is this one..

 

http://rrsignal.com/projects.htm

 

I have the schematic at home somewhere and will dig it out. There is a dimming 
mod using a transistor/pot that works quite nicely. Mine has been running for 
about 8 years now with no issues. it uses the MM5314 clock chip, so no 
software to be seen and is mains referenced, but keeps remarkably good time 
over long periods (it sits next to a few GPS disciplined clocks).

 

Cheers,

 

Nick

 

On Tue, Mar 7, 2023 at 7:18 AM Batareyka mailto:batar...@gmail.com> > wrote:

There are two ways to solve this problem.
1. Software, but as the author of the topic, there is no software and the 
possibility of editing it (I
  I think so), then method number 2 remains.
2. The 4511 chip has a wide power supply range from 3-16 volts. Put the power 
regulator and turn it up to 4 volts, which will change the output power of the 
lamp filaments accordingly.
Checked more than once.

вторник, 7 марта 2023 г. в 17:02:08 UTC+2, theold...@gmail.com 
 : 

Martin,

 

How did you do that? (schematic)

 

Problem with a pot (or any resistor) is that you would need one for each 
element (7 per tube) since you cannot put one in the common line. Each filament 
draws about 22mA, so depending on the number displayed, the current would be 
anywhere between 44 and 154 mA. This would result in different voltage drops 
depending on the number displayed. It would result in uneven light output. Same 
reason why you could not use a single current regulator pre tube, but one per 
filament would be needed. A voltage regulator (such as a simple diode) does not 
have that disadvantage.

 

Bill v

 

From: neoni...@googlegroups.com   
mailto:neoni...@googlegroups.com> > On Behalf Of 
martin martin
Sent: Tuesday, March 07, 2023 9:09 AM
To: neoni...@googlegroups.com  
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

How about this clock I built in the early 80s? 5314  clock chip.  I used a 1k 
pot for dimming.  Has been running for  many moons now!

 

 

 

 

~

mcve...@gmail.com  

 

 

On Tue, Mar 7, 2023 at 5:55 AM gregebert mailto:greg...@hotmail.com> > wrote:

Under "normal" circumstances, I agree that individual current regulators add a 
lot of circuitry. The reality is that most tubes are no longer manufactured, so 
their numbers are dwindling as the price increases, essentially irreplaceable. 
You wouldn't believe the lengths I went towards protecting NIMO tubes in the 
clock I'm still working on.

 

I've debated about building a numitron clock, and the route I think I will go 
with uses LED 'filaments' that are used in retro light bulbs. Filaments scare 
the heck out of me because they will fail from thermal cycling, but there is no 
alternative for NIMO and VFD displays.

On Monday, March 6, 2023 at 11:35:22 AM UTC-3 theold...@gmail.com 
  wrote:

Using a current limiter sounds like a LOT of circuitry, 7 times the number of 
tubes? I simply use a forward biased diode to drop the voltage, about 0.7 for a 
standard silicon diode, and about 0.3 for a Schottky. That requires only one or 
perhaps two diodes for the whole set of tubes. Perhaps not as accurate, but 
definitely a whole lot simpler.

 

  

 

 

 

 

From: neoni...@googlegroups.com   
mailto:neoni...@googlegroups.com> > On Behalf Of 
gregebert
Sent: Monday, March 06, 2023 8:13 AM
To: neonixie-l mailto:neoni...@googlegroups.com> >
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

Very good info, Moses.

 

>From that, I would target the  operating current well-below 20mA to prolong 
>the life of the display. You could use an NPN current-limiter (driver) driven 
>from 5V TTL logic. Let me know if you need circuit details, but it's a very 
>simple design (1 NPN + 1 emitter resistor). As a starting point, a 270 ohm 
>emitter resistor will limit 

RE: [neonixie-l] Re: IV-9 numitron lifespan

[theoldphart2]

Not as easy as that sounds. 

 

If you want to use software (I presume PWM) you cant use a 4511 anymore since 
their greatest advantage (besides the BCD to 7 segment decoding) is its latch 
function. No way to implement any software based dimming. This would require a 
very drastic hardware redesign.

 

Turning the 5V line down would work, but may cause issues with the rest of your 
circuit. A dedicated supply for the 4511’s could work, but depending on the 
final setting, there would be a discord in logic levels between the rest of the 
circuit and the 4511. Nasty, could result in unreliable communications. Level 
shifters could fix that, but wow, we are getting complicated again.

 

The diode is still the best solution in my mind. Working with silicon and 
Schottky diodes you can obtain steps of 0.3V, 0.6V, 0.9V, 1.0V, 1.2V etc. Some 
diodes have slightly different forward voltage drops, so with a bit of 
searching you can obtain a lot of very simple options. Using jumpers of DIP 
switches you can even make it very simple to adjust. Why all the complicated 
solutions?

 

Bill v

 

From: neonixie-l@googlegroups.com  On Behalf Of 
Batareyka
Sent: Tuesday, March 07, 2023 10:19 AM
To: neonixie-l 
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

There are two ways to solve this problem.
1. Software, but as the author of the topic, there is no software and the 
possibility of editing it (I
  I think so), then method number 2 remains.
2. The 4511 chip has a wide power supply range from 3-16 volts. Put the power 
regulator and turn it up to 4 volts, which will change the output power of the 
lamp filaments accordingly.
Checked more than once.

вторник, 7 марта 2023 г. в 17:02:08 UTC+2, theoldpha...@gmail.com 
 : 

Martin,

 

How did you do that? (schematic)

 

Problem with a pot (or any resistor) is that you would need one for each 
element (7 per tube) since you cannot put one in the common line. Each filament 
draws about 22mA, so depending on the number displayed, the current would be 
anywhere between 44 and 154 mA. This would result in different voltage drops 
depending on the number displayed. It would result in uneven light output. Same 
reason why you could not use a single current regulator pre tube, but one per 
filament would be needed. A voltage regulator (such as a simple diode) does not 
have that disadvantage.

 

Bill v

 

From: neoni...@googlegroups.com   
mailto:neoni...@googlegroups.com> > On Behalf Of 
martin martin
Sent: Tuesday, March 07, 2023 9:09 AM
To: neoni...@googlegroups.com  
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

How about this clock I built in the early 80s? 5314  clock chip.  I used a 1k 
pot for dimming.  Has been running for  many moons now!

 

 

 

 

~

mcve...@gmail.com  

 

 

On Tue, Mar 7, 2023 at 5:55 AM gregebert mailto:greg...@hotmail.com> > wrote:

Under "normal" circumstances, I agree that individual current regulators add a 
lot of circuitry. The reality is that most tubes are no longer manufactured, so 
their numbers are dwindling as the price increases, essentially irreplaceable. 
You wouldn't believe the lengths I went towards protecting NIMO tubes in the 
clock I'm still working on.

 

I've debated about building a numitron clock, and the route I think I will go 
with uses LED 'filaments' that are used in retro light bulbs. Filaments scare 
the heck out of me because they will fail from thermal cycling, but there is no 
alternative for NIMO and VFD displays.

On Monday, March 6, 2023 at 11:35:22 AM UTC-3 theold...@gmail.com 
  wrote:

Using a current limiter sounds like a LOT of circuitry, 7 times the number of 
tubes? I simply use a forward biased diode to drop the voltage, about 0.7 for a 
standard silicon diode, and about 0.3 for a Schottky. That requires only one or 
perhaps two diodes for the whole set of tubes. Perhaps not as accurate, but 
definitely a whole lot simpler.

 

  

 

 

 

 

From: neoni...@googlegroups.com   
mailto:neoni...@googlegroups.com> > On Behalf Of 
gregebert
Sent: Monday, March 06, 2023 8:13 AM
To: neonixie-l mailto:neoni...@googlegroups.com> >
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

Very good info, Moses.

 

>From that, I would target the  operating current well-below 20mA to prolong 
>the life of the display. You could use an NPN current-limiter (driver) driven 
>from 5V TTL logic. Let me know if you need circuit details, but it's a very 
>simple design (1 NPN + 1 emitter resistor). As a starting point, a 270 ohm 
>emitter resistor will limit current to 16mA.

 

Do you hear any noise with your PWM running at 1600Hz ?  If not, I would stick 
with PWM and not use the NPN driver, as it's not necessary. As 

RE: [neonixie-l] Re: IV-9 numitron lifespan

[theoldphart2]

Martin,

 

How did you do that? (schematic)

 

Problem with a pot (or any resistor) is that you would need one for each 
element (7 per tube) since you cannot put one in the common line. Each filament 
draws about 22mA, so depending on the number displayed, the current would be 
anywhere between 44 and 154 mA. This would result in different voltage drops 
depending on the number displayed. It would result in uneven light output. Same 
reason why you could not use a single current regulator pre tube, but one per 
filament would be needed. A voltage regulator (such as a simple diode) does not 
have that disadvantage.

 

Bill v

 

From: neonixie-l@googlegroups.com  On Behalf Of 
martin martin
Sent: Tuesday, March 07, 2023 9:09 AM
To: neonixie-l@googlegroups.com
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

How about this clock I built in the early 80s? 5314  clock chip.  I used a 1k 
pot for dimming.  Has been running for  many moons now!

 

 

 

 

~

  mcvei...@gmail.com

 

 

On Tue, Mar 7, 2023 at 5:55 AM gregebert mailto:gregeb...@hotmail.com> > wrote:

Under "normal" circumstances, I agree that individual current regulators add a 
lot of circuitry. The reality is that most tubes are no longer manufactured, so 
their numbers are dwindling as the price increases, essentially irreplaceable. 
You wouldn't believe the lengths I went towards protecting NIMO tubes in the 
clock I'm still working on.

 

I've debated about building a numitron clock, and the route I think I will go 
with uses LED 'filaments' that are used in retro light bulbs. Filaments scare 
the heck out of me because they will fail from thermal cycling, but there is no 
alternative for NIMO and VFD displays.

On Monday, March 6, 2023 at 11:35:22 AM UTC-3 theoldpha...@gmail.com 
  wrote:

Using a current limiter sounds like a LOT of circuitry, 7 times the number of 
tubes? I simply use a forward biased diode to drop the voltage, about 0.7 for a 
standard silicon diode, and about 0.3 for a Schottky. That requires only one or 
perhaps two diodes for the whole set of tubes. Perhaps not as accurate, but 
definitely a whole lot simpler.

 

  

 

 

 

 

From: neoni...@googlegroups.com   
mailto:neoni...@googlegroups.com> > On Behalf Of 
gregebert
Sent: Monday, March 06, 2023 8:13 AM
To: neonixie-l mailto:neoni...@googlegroups.com> >
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

Very good info, Moses.

 

>From that, I would target the  operating current well-below 20mA to prolong 
>the life of the display. You could use an NPN current-limiter (driver) driven 
>from 5V TTL logic. Let me know if you need circuit details, but it's a very 
>simple design (1 NPN + 1 emitter resistor). As a starting point, a 270 ohm 
>emitter resistor will limit current to 16mA.

 

Do you hear any noise with your PWM running at 1600Hz ?  If not, I would stick 
with PWM and not use the NPN driver, as it's not necessary. As long as the PWM 
cycle-time is shorter than the thermal time-constant of the filament (probably 
a few milliseconds), you should be fine. I think you can measure the thermal 
time-constant of the filament with a phototransistor and a scope. Starting at a 
low PWM frequency, the phototransistor will show fluctuations in the bulb's 
intensity. As the frequency is increased, you should see the amplitude decrease 
towards zero. I've never actually done this but I'm pretty sure it will work. 
You have to use a phototransistor (or photodiode); a CdS photosensor will have 
too-slow of a response time.

On Monday, March 6, 2023 at 2:37:45 AM UTC-3 Moses wrote:

The TI CD4511B datasheet lists the lists the *minimum* high level output (at 5v 
VDD) of 4.1v but typical is 4.55v, maybe others are different?

 

https://www.ti.com/lit/ds/symlink/cd4511b.pdf

At 4.55v the segment current on the IV-9 is going to be about 25ma. Typical 
IV-9 segment current is about 20ma I believe, so that would be a 25% overdrive.

 

I've put up a drive voltage vs segment current table on my site, maybe it's 
useful to someone: http://www.neonixie.com/IV-9-6D-RR/#tech

 

I settled with powering the tubes in my designs in one of two ways.. 5.0v 
direct with a recommended PWM of about 65% (the 165 (out of 255) value in the 
table) OR 5v through a regular silicon diode, dropping the voltage to about 
4.2v at the tube and PWM that to 76%. Both result in a segment current of 20ma. 
Don't know if one or the other is better in regards to lifetime, I was not able 
to find any official sources of information. I experimented with driving them 
using a 3.3v regulator.. but at that voltage they were a bit dim.

 

NOTE: The IV-9 datasheet does mention to avoid running the tubes at a frequency 
between 105 and 1000 Hz, presumably to avoid mechanical resonance. I elected to 
run them at 

RE: [neonixie-l] Re: IV-9 numitron lifespan

[theoldphart2]

Using a current limiter sounds like a LOT of circuitry, 7 times the number of 
tubes? I simply use a forward biased diode to drop the voltage, about 0.7 for a 
standard silicon diode, and about 0.3 for a Schottky. That requires only one or 
perhaps two diodes for the whole set of tubes. Perhaps not as accurate, but 
definitely a whole lot simpler.

 



 

 

 

From: neonixie-l@googlegroups.com  On Behalf Of 
gregebert
Sent: Monday, March 06, 2023 8:13 AM
To: neonixie-l 
Subject: Re: [neonixie-l] Re: IV-9 numitron lifespan

 

Very good info, Moses.

 

>From that, I would target the  operating current well-below 20mA to prolong 
>the life of the display. You could use an NPN current-limiter (driver) driven 
>from 5V TTL logic. Let me know if you need circuit details, but it's a very 
>simple design (1 NPN + 1 emitter resistor). As a starting point, a 270 ohm 
>emitter resistor will limit current to 16mA.

 

Do you hear any noise with your PWM running at 1600Hz ?  If not, I would stick 
with PWM and not use the NPN driver, as it's not necessary. As long as the PWM 
cycle-time is shorter than the thermal time-constant of the filament (probably 
a few milliseconds), you should be fine. I think you can measure the thermal 
time-constant of the filament with a phototransistor and a scope. Starting at a 
low PWM frequency, the phototransistor will show fluctuations in the bulb's 
intensity. As the frequency is increased, you should see the amplitude decrease 
towards zero. I've never actually done this but I'm pretty sure it will work. 
You have to use a phototransistor (or photodiode); a CdS photosensor will have 
too-slow of a response time.

On Monday, March 6, 2023 at 2:37:45 AM UTC-3 Moses wrote:

The TI CD4511B datasheet lists the lists the *minimum* high level output (at 5v 
VDD) of 4.1v but typical is 4.55v, maybe others are different?

 

https://www.ti.com/lit/ds/symlink/cd4511b.pdf

At 4.55v the segment current on the IV-9 is going to be about 25ma. Typical 
IV-9 segment current is about 20ma I believe, so that would be a 25% overdrive.

 

I've put up a drive voltage vs segment current table on my site, maybe it's 
useful to someone: http://www.neonixie.com/IV-9-6D-RR/#tech

 

I settled with powering the tubes in my designs in one of two ways.. 5.0v 
direct with a recommended PWM of about 65% (the 165 (out of 255) value in the 
table) OR 5v through a regular silicon diode, dropping the voltage to about 
4.2v at the tube and PWM that to 76%. Both result in a segment current of 20ma. 
Don't know if one or the other is better in regards to lifetime, I was not able 
to find any official sources of information. I experimented with driving them 
using a 3.3v regulator.. but at that voltage they were a bit dim.

 

NOTE: The IV-9 datasheet does mention to avoid running the tubes at a frequency 
between 105 and 1000 Hz, presumably to avoid mechanical resonance. I elected to 
run them at 1600 Hz.

 

I looked through some of my testing data.. at a segment current of 3mA the 
segments are visible, 2mA they are "barely visible" and at 1mA I noted them as 
not visible. Keeping the unlit segments warm with a slight current seems to 
make the most sense to me. It's all software on my clock so maybe an option for 
the next revision.

 

That's all I know so far.

 

Regards,

-Moses

On Saturday, March 4, 2023 at 5:52:05 AM UTC-8 theold...@gmail.com 
  wrote:

Hi Chris,

 

The numitrons are driven by a 4511 decoder, and according to their data sheets 
the max. output at that voltage is 4.1 V, so that is well within specification 
for the tube. Yes, I agree, lowering the voltage even further should increase 
lifespan.

 

Bill v

 

From: neoni...@googlegroups.com   
mailto:neoni...@googlegroups.com> > On Behalf Of 
Chris
Sent: Saturday, March 04, 2023 8:19 AM
To: neonixie-l mailto:neoni...@googlegroups.com> >
Subject: [neonixie-l] Re: IV-9 numitron lifespan

 

Hi,

While i am not sure for the IV9 numitrons have a look at the DA2300 lifetime 
expectancy,

  

 



Basically reducing the voltage increases the life expectancy exponentially. 

So i usually run my numitrons at 4.5V or lower and have had no issues so far.

On Friday, March 3, 2023 at 8:05:48 PM UTC+1 theold...@gmail.com 
  wrote:

I seem to recall there was some discussion on the life expectancy of IV-9 
numitrons some time ago. 

 

In 2015 I built a number of clocks with these tubes, and they started failing 
last year. The clock in the picture is on my bench now, the three good tubes 
were replaced in November last year. So today all 6 tubes will be replaced. I 
have replaced all 6 tubes on a few other clocks also. One or more segments will 
no longer light up, and I do not 

RE: [neonixie-l] Re: IV-9 numitron lifespan

[theoldphart2]

Hi Chris,

 

The numitrons are driven by a 4511 decoder, and according to their data sheets 
the max. output at that voltage is 4.1 V, so that is well within specification 
for the tube. Yes, I agree, lowering the voltage even further should increase 
lifespan.

 

Bill v

 

From: neonixie-l@googlegroups.com  On Behalf Of 
Chris
Sent: Saturday, March 04, 2023 8:19 AM
To: neonixie-l 
Subject: [neonixie-l] Re: IV-9 numitron lifespan

 

Hi,

While i am not sure for the IV9 numitrons have a look at the DA2300 lifetime 
expectancy,

   

Basically reducing the voltage increases the life expectancy exponentially. 

So i usually run my numitrons at 4.5V or lower and have had no issues so far.

On Friday, March 3, 2023 at 8:05:48 PM UTC+1 theoldpha...@gmail.com 
  wrote:

I seem to recall there was some discussion on the life expectancy of IV-9 
numitrons some time ago. 

 

In 2015 I built a number of clocks with these tubes, and they started failing 
last year. The clock in the picture is on my bench now, the three good tubes 
were replaced in November last year. So today all 6 tubes will be replaced. I 
have replaced all 6 tubes on a few other clocks also. One or more segments will 
no longer light up, and I do not see any blackening of the glass tube (The 
black you see in the picture is my permanent marker, s I will not replace the 
wrong tube when I disconnect the power).

 

The tubes are driven directly from a 4511 chip on a 5V power line.

 

There does not seem to be any order in which they fail, so I do not have the 
feeling that any of the tubes are significantly impacted by thermal stresses 
from flashing on and off. I would say based on my experience with them, the 
expected lifespan is about 7 years of continues use.

 

Bill v

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RE: [neonixie-l] flicker-flame lamps

[theoldphart2]

I was told (as the guy in the video also discusses) it is the same effect as 
what is called a “Jacob’s Ladder”, the effect introduced by local gas pressure 
changes due to the heat produces by the arc. The flicker lamp is designed to 
let it happen, rather than preventing it.

 

Bill v

 

From: neonixie-l@googlegroups.com  On Behalf Of 
Adrian Godwin
Sent: Monday, December 12, 2022 5:28 PM
To: neonixie-l 
Subject: [neonixie-l] flicker-flame lamps

 

https://www.youtube.com/watch?v=nyYjnV99wfM

 

Anyone able to answer how these lamps work and why they're so unstable ? The 
answer by 'Butanik' sounds plausible but IANAP (I am not a physicist). 

 

-adrian

 

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RE: [neonixie-l] Nixie clock sighting

[theoldphart2]

Netflix

 

From: neonixie-l@googlegroups.com  On Behalf Of 
blkadder
Sent: Saturday, December 03, 2022 11:09 PM
To: neonixie-l 
Subject: Re: [neonixie-l] Nixie clock sighting

 

What series is this?  I always like seeing Nixies on TV.

On Saturday, December 3, 2022 at 10:40:56 PM UTC-5 Richard Scales wrote:

Similar sightings over on the FB group - popular with us nixie fans this series 
is!

- Richard

 

On Sunday, 4 December 2022 at 03:16:23 UTC OrangeGlow wrote:

Also at the end of the first episode.

On 12/3/2022 4:12 PM, 'Grahame' via neonixie-l wrote:

  

 

"Wednesday" Episode 6 about 27 minutes.

 

 

 

 

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RE: [neonixie-l] Any interest in IV-9 numitron clock kit?

[theoldphart2]

 

I made an IV-9 based clock some years ago which was featured in the Nuts & 
Volts magazine September 2016. I used 4511 BCD to seven segment decoders with 
latch function to drive the tubes directly. An HC164 shift register is clocked 
by a mpu to make sure the data gets to the correct tube. The tubes therefore 
are not multiplexed, and the whole thing can drive as many tubes as you want 
with only one 8 bit port. There are a few hundred of this clock in circulation, 
and after 6 years I am starting to see the odd tube failure aside from a couple 
of “infant mortalities”. Below is an excerpt from the schematic showing the 
part related to the tubes. JP1 is simply a way to lower the voltage of the 
tubes by 0.7V if so desired. 

 



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Re: [neonixie-l] Scope clock recommendations

[theoldphart2]

You're probably correct on that, I read further down that any analog scope 
would do. Since it is currently not available I will keep it on my short list.
Thanks again, Bill


Sent from my Samsung Galaxy Tab® S

 Original message 
From: "H. Carl Ott"  
Date: 2018-09-14  1:48 PM  (GMT-05:00) 
To: neonixie-l@googlegroups.com 
Subject: Re: [neonixie-l] Scope clock recommendations 

Oh, I think you would be ok with an analog scope. Slow DSOs can have problems 
with analog signals like this. 
 He does not mentions any minimum bandwidth requirements, but the DACs he uses 
are not that fast.
Just to sidetrack the conversation a bit. There is a fascinating thread over on 
eevblog about a scope clock build,  Really nifty and compact implementation. A 
link for the interested: 
https://www.eevblog.com/forum/projects/maybe-risk-a-guess-what-thats-gonna-be/


carl

Henry Carl Ott   N2RVQ    hcarl...@gmail.com

On Fri, Sep 14, 2018 at 1:29 PM Bill van Dijk  wrote:
Hi Carl, Thanks for the suggestion. I’m not sure if this one would work though, 
in the web site it mentions the kit does not work well with low end (digital) 
scopes. Mine is not digital, but surely low end. Perhaps I’ll PM the author. 
Thanks again, Bill From: neonixie-l@googlegroups.com 
[mailto:neonixie-l@googlegroups.com] On Behalf Of H. Carl Ott
Sent: Friday, September 14, 2018 12:58 PM
To: neonixie-l@googlegroups.com
Subject: Re: [neonixie-l] Scope clock recommendations Could wait for a 
Dutchtronix. http://www.dutchtronix.com/ScopeClockH3-1-Enhanced.htm 
 I have a kit on the shelf, but never got around to assembling it, so can't 
directly recommend it.  carl

Henry Carl Ott   N2RVQ    hcarl...@gmail.com  On Fri, Sep 14, 2018 at 12:32 PM 
Bill van Dijk  wrote:Hi Nick, Nice kit. This is a 
complete kit though, not a conversion. I would like to use as much as the 
original hardware as possible, at least the HV, and X-Y amplifiers. Thanks, 
Bill From: neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On 
Behalf Of Nicholas Stock
Sent: Friday, September 14, 2018 10:38 AM
To: neonixie-l@googlegroups.com
Subject: Re: [neonixie-l] Scope clock recommendations 
http://www.sgitheach.org.uk/scope3.html Built many of themstill need to 
make some casesI am a little biased though...;-) (Pharma) Nick On Fri, Sep 
14, 2018 at 7:07 AM Bill van Dijk  wrote:I was lucky 
enough to pick up a complete, unbuilt, 5MHz Heathkit oscilloscope kit at a 
local ham flea market last weekend. It has no value as a test instrument 
anymore, so it begs to become a scope clock. Does someone have a recommendation 
for a conversion kit? Ideally I would be able to build the kit inside the scope 
enclosure, possibly by omitting boards that are not essential to the clock? 
These kits are fairly “roomy” inside.Any recommendations and advise would be 
greatly appreciated. Thanks, Bill -- 
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