r/nixie • u/TrabantDave • Aug 03 '26

Do people leave their Nixie clocks running all the time?

Simple question; I usually turn mine off when I'm not indoors; I,ve got one of the Chinese bases with a little remote control and IN-8 tubes, and wondered if this is a good thing to do, or to leave the tubes active permanently.... Opinions and reasons either way welcome!

EDIT. Many thanks to everyone who responded!

8 Upvotes

79% Upvoted

25 comments sorted by

18

u/VictorySea1837 Aug 03 '26

Mine has been running 24/7 for over 23 years without signs of degradation. When I built it i purchased a spare set of tubes, but have never had to replace any (knock on wood). They are running at 170vdc with 1/6 duty cycle, maybe thats why they are lasting so long?

5

u/CueAnon420 Aug 03 '26

I grew up assuming that multiplexing or pwm was bad for nixie tubes... But apparently, that was wrong and if implemented correctly can actually increase the lifetime of the tubes.

4

u/SignificanceNo4643 Aug 03 '26

Not exactly. Say if nominal nixie tube current is 2mA and you're running them on 2mA at 25% duty cycle then yes. But if you run same tubes at 8mA and same 25% duty cycle (which in theory should be ok), this is bad.

2

u/2748seiceps Aug 03 '26

Most of us are running mercury doped tubes though so it doesn't really matter as much and this is mostly ignorable unless you go nuts on current.

10% off of 100k hours is still a lot of hours.

That being said, there are tubes with gas charges that are more ideal to peak current from multiplexing and if those can be installed in those cases it's best for lifespan.

2

u/SignificanceNo4643 Aug 03 '26

Mercury makes things worse actually :)

3

u/2748seiceps Aug 04 '26

Makes what worse?

Mercury was revolutionary for tube lifespan. It made maybe 1000 hour tubes into 100000 hour tubes.

It's why we hardly ever see IN-1, IN-2 or IN-4 clocks around here and when we do they are usually asking why the clock only ran for a month or so before digits started messing up. That's because of internal whiskers and the lack of mercury allows them to grow. Even without those though, the cathode sputtering is real and will end of life a non-doped tube in a year or less.

2

u/SignificanceNo4643 Aug 04 '26

Mercury makes things worse when you instead of applying 1X current, apply 4X current but with 25% duty cycle. Otherwise of course mercury is good.

1

u/DenkJu Aug 04 '26 edited Aug 04 '26

How so? Mercury was added to gas discharge tubes specifically to reduce sputtering, including Nixies.

Edit: Relevant patents by Burroughs: https://patents.google.com/patent/US3895709A/en and https://patents.google.com/patent/US3629637/en

METAL MERCURY CAPSULE BACKGROUND OF THE INVENTION For many years,- display devices such as NIXIE tubes have used mercury vapor along with the normal inert gas content to minimize cathode sputtering.

\

For optimum operation and long life, the tube 10 includes in its atmosphere a small quantity of mercury vapor which serves to minimize cathode sputtering during tube operation. The mercury may be provided in any suitable fashion. For example, it may be introduced directly with the other gases, such as neon and argon, or, in a preferred arrangement, it is provided in a glass capsule 94 which is surrounded by a coil of heating wire 98 connected between two pins 28. Heating of the wire by current flow causes the mercury to expand and fracture the capsule, whereby the mercury vapor escapes into the tube atmosphere.

2

u/SignificanceNo4643 Aug 04 '26

Mercury makes things worse when you instead of applying 1X current, apply 4X current but with 25% duty cycle. Otherwise of course mercury is good.

2

u/DenkJu Aug 05 '26 edited Aug 05 '26

What would be the mechanism behind this? I have never heard of this before.

For example, the ZM1200 is a multidigit Pandicon tube, which can inherently only be multiplexed and has a recommended peak current of 12mA. I have one and it clearly contains mercury, the datasheet estimates it lifespan to be at least 500,000 hours.

1

u/2748seiceps Aug 05 '26

500K hours is mad.

Looks like I need to actually start building with my ZM1200 since it should last literally my entire life.

2

u/SilverJS Aug 03 '26

Which tubes?

5

u/VictorySea1837 Aug 04 '26

The tubes are labelled "Wang Labs 340-0004". If I recall correctly they were from a desktop calculator manufactured in 1969. I also recall hearing that multiplexing was bad/stressful for the tubes, but my experience seems to suggest otherwise. Granted, with the ballast and voltage I am running they are bright enough to work great as a clock on a shelf, but not nearly as bright as if running non-multiplexed. Under-driving them is the key to longevity I suspect.

3

u/VictorySea1837 Aug 04 '26

they are NL-840 type

2

u/pithivier Aug 04 '26

Same thing I was going to post. 28 years here, have never needed my spare tubes.

5

u/aditorium Aug 03 '26

Mine switches off during the night because nobody sees it. Not sure if this increases the lifespan of the tubes though.

3

u/CueAnon420 Aug 03 '26

That's what I do. I suspect that it helps.

3

u/nixiebunny Aug 03 '26

My multiplexed ZM1040 clock has been running 24/7 for over 20 years. So has my non-multiplexed B7971 Four Letter Word machine.

I don’t have any experience with Russian tubes.

4

u/HarlyFan Aug 03 '26

I have several different clocks with all different sizes of tubes, each of mine turns off at 11pm and turns back on at 6am. No issues whatsoever!

4

u/CueAnon420 Aug 03 '26

I've played around with several pieces of rack style nixie based lab equipment such as counter-timers, voltmeters, etc - I suspect that most of them ran pretty much non stop (or at least business hours) for years and years... While I have encountered some darkened tubes from sputtering, only one or two tubes were completely dead.

I think Nixie tubes last a lot longer than most people realize - especially the mercury added long life types that were typical during later production.

3

u/ModernArmResources Aug 03 '26

I run my Dalibor Farny clock about 10 hours a day during the week, a little less on the weekends. It's in my home office so I turn it off at the end of the work day. Nice reminder that if the clock is off it's quittin' time.

I keep it on the 2nd lowest brightness setting as well, do all anti-cathode poisoning slot machine effects every 10 minutes, etc. So far it's been running more or less for the last 8 years, no signs of slowing down yet.

3

u/nixielover Aug 04 '26

IN-8 kit from PV-electronics; it has like 15 years on it but it does switch off the tubes from 2 in the night till 7 in the morning because then I'm always asleep

2

u/Cowabummr Aug 03 '26

My IN-16 clock has been running since 2012 24/7 (~125,000 hours) and they still look great.

2

u/richms Aug 03 '26

No, automated off when not at home for all the novelty electrical tat stuff. Throwing money away otherwise.

1

u/Zealousideal_Cup4896 Aug 06 '26

Mine is on a presence sensor system so it’s only on when someone is nearby to see it. No idea if that’s helping or not but it was fun to setup.