IN-18 gone bad.

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Terry S

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Jan 22, 2014, 8:19:07 AM1/22/14
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One of the IN-18s in my Nixichron has started to fail. I don't know if it's cathode poisoning or some other failure mode.
 
In the 10's hours position, several of the digits are not lighting completely, they are dark toward the bottom of the tube, probably the bottom 1/3 of the numeral.
 
This happened rather suddenly, or at least I only noticed it recently. The "1" digit is fine, and that's what is lit most of the time. The other digits only come into play during display of the GPS coordinates every 1/4 hour. As they scroll across the clock, I can see the bad digits.
 
Has anyone seen this particulat failure mode in an IN-18? Bottom of some digits failing to glow?
 
I do have a couple spare tubes, but they have no hours on them. I'll try one to be certain it's just the tube. But I'd actually like to find a used tube, something with several years worth of use on it, so the brightness will be a better match.
 
Terry

John Rehwinkel

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Jan 22, 2014, 8:36:58 AM1/22/14
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> One of the IN-18s in my Nixichron has started to fail. I don't know if it's cathode poisoning or some other failure mode.
>
> In the 10's hours position, several of the digits are not lighting completely, they are dark toward the bottom of the tube, probably the bottom 1/3 of the numeral.

Sounds like cathode poisoning.

> This happened rather suddenly, or at least I only noticed it recently. The "1" digit is fine, and that's what is lit most of the time. The other digits only come into play during display of the GPS coordinates every 1/4 hour. As they scroll across the clock, I can see the bad digits.

Yeah, cathode poisoning happens when not all the digits are used enough.

> I do have a couple spare tubes, but they have no hours on them. I'll try one to be certain it's just the tube. But I'd actually like to find a used tube, something with several years worth of use on it, so the brightness will be a better match.

It's worth trying to depoison that one. The easy way is to swap it with one of the other digits that gets used more evenly. The quick way is to run those other digits for a bit a higher-than-normal current until they light fully again.

- John

Adam Jacobs

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Jan 22, 2014, 10:27:13 AM1/22/14
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This is an issue that is most obvious on clocks with lots of
functionality. If there are different modes/menus that display numerals
on a tube that are not normally lit as part of the clock, then you'll
see this. Best advice is to take full advantage of automated
cathode-poisoning prevention routines.
Clocks that don't have any menus, i.e. they don't ever display a
numeral on a tube that wouldn't be displayed as part of the standard
clock, still have this problem but it's not anywhere near as obvious.
For example: If the 10-minutes tube only ever displays 0-5 in the course
of being a clock and I don't have any additional menus or modes that
might try to display something besides those values, then the critical
poisoning of 6-9 doesn't matter to me.

John is right. Try to repair the cathode poisoning if it is still fairly
mild. I've had great luck in the past doing this with IN-8-2's. [I
learned the hard way on some of my earliest clocks regarding current
limiting resistors. :S]

-Adam

Gene Mark Segal

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Jan 22, 2014, 10:30:40 AM1/22/14
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You're all wrong, it's leaking gas through the pins.

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Terry S

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Jan 22, 2014, 10:41:58 AM1/22/14
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Gene, please explain how you know this is the case.
 
Thanks
 
Terry

Gene Mark Segal

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Jan 22, 2014, 10:56:13 AM1/22/14
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When you have a sudden performance issue, it's gas. Especially when large sections of large-area cathodes go dim. Poisoning from sputtering affects small sections and is observed over longer periods of time. I'll bet that tube will start going pink soon. 

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Terry S

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Jan 22, 2014, 1:34:51 PM1/22/14
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Thanks Gene -- I'll keep an eye on it and let you know.
 
Terry
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Dan Hollis

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Jan 23, 2014, 1:39:41 AM1/23/14
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Yep, this exactly happened to me. A tube suddenly started having problems
lighting some digits. Then eventually it stopped working altogether.

I caused it because I was swapping the tubes too much. The repeated
removal/insertions caused the tube to leak at the pins.

I still want to rotate the tubes, but I need to come up with a surrogate
socket so I can swap the tubes without stressing the pins.

-Dan
> To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/DCC680D3-8D1C-458F-99E5-0BE23298FD8E%40earthlink.net.

John Rehwinkel

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Jan 23, 2014, 9:26:25 AM1/23/14
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> I caused it because I was swapping the tubes too much. The repeated removal/insertions caused the tube to leak at the pins.
>
> I still want to rotate the tubes, but I need to come up with a surrogate socket so I can swap the tubes without stressing the pins.

A ZIF nixie socket! Now that would be quite a thing! That would also dodge the usual problem in home-made sockets of having the grippers both float and exert proper tension, by moving the tensioning function elsewhere. Time to start scribbling and thinking about milling out some interesting shapes.

- John

Ron Schuster

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Jan 23, 2014, 9:47:36 AM1/23/14
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 [I learned the hard way on some of my earliest clocks regarding current limiting resistors. :S]

 Could you please elaborate on what you were referring to here?

AntiqueSounds

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Jan 23, 2014, 11:05:06 AM1/23/14
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Zero Insertion Force (ZIF)  (http://en.wikipedia.org/wiki/Zero_insertion_force) sockets for nixies would be SWEET!  

Dan Hollis

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Jan 23, 2014, 2:22:59 PM1/23/14
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I would definitely pay for ZIF IN-18 sockets :)

-Dan
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Terry S

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Jan 24, 2014, 4:30:05 PM1/24/14
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I don't think ZIF sockets are necessary -- too much complexity -- but a LIF (low insertion force) socket would be cool.
 
Imagine a socket consisting of a solid round cylinder core, with spring tensioned contacts surrounding the core, that would press against the pins when the tube is placed over the core.
Similar, non conducting "dummy" tensioned contacts could be on the opposite side of the pins, held in place by an outer ring. All contacts would be stamped concave to help position the tube.
 
Some other mechanical retension method might be needed to secure the tube, perhaps a wire over the top like you've all seen in some equipment sockets.
 
Who's got a 3D printer?
 
Terry

Cqr

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Jan 24, 2014, 6:34:28 PM1/24/14
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How about this for a ZIF design:

The contacts take the form of tubes with slits cut axially all round leaving rings uncut top and bottom to form a sort of tubular cage with no roof or floor.

If the top ring is twisted while the bottom one is held the tube will collapse to a hyperboloid "cooling tower" shape which would grip a pin.

A suitable mechanism for the twisting would be an insulating collar (perhaps ceramic or hard resin) running round the top of the socket with gear teeth on the inner face that engage in either matching teeth in the top rings of the sockets or perhaps the top of the slits.

So you would drop the tube in then twist the top of the socket 90 degrees or so... Some form of latching would be needed of course.

Hope that makes some sort of sense... 
I'll try and knock up a diagram when I get to my computer as this needs getting out of my head properly now :)

Cheers,
         Robin.

Quixotic Nixotic

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Jan 25, 2014, 12:56:32 AM1/25/14
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Spencer W

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Jan 25, 2014, 1:07:44 AM1/25/14
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But it's all hand selected!

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Michel van der Meij

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Jan 25, 2014, 1:10:21 AM1/25/14
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I would feel a bit anxious to leave a wooden clock switched on for say 24 hrs/day, especially if it is not my own design. Just worried it would catch fire at a moment I am asleep or not there. Is that just me or do other people have that same worry?

I quite like the design though, not an immediate "wow" factor as some other clocks, but I wouldn't mind having a clock like this one.
 
Michel
 
 

Quixotic Nixotic

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Jan 25, 2014, 1:21:25 AM1/25/14
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On 25 Jan 2014, at 06:10, Michel van der Meij wrote:

> I would feel a bit anxious to leave a wooden clock switched on for say 24 hrs/day, especially if it is not my own design. Just worried it would catch fire at a moment I am asleep or not there. Is that just me or do other people have that same worry?

He does say "I have a working model of the clock which I have fired up, run for days, and has had no issues."

John S

Michel van der Meij

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Jan 25, 2014, 1:29:07 AM1/25/14
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yes, but how about after 5 or 10 years and say 100 clocks. It's still wood and as we all know, electronic parts that fail can get very hot.

Michel
 
on Jan 25, 2014, Quixotic Nixotic <nixc...@jsdesign.co.uk> wrote:
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Spencer

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Jan 25, 2014, 1:29:34 AM1/25/14
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All of my wooden clocks have ran for years with no issues.


From: Quixotic Nixotic <nixc...@jsdesign.co.uk>
To: neoni...@googlegroups.com
Sent: Saturday, January 25, 2014 12:21 AM
Subject: Re: [neonixie-l] Steampunk
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jb-electronics

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Jan 26, 2014, 12:53:50 PM1/26/14
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Hi guys,

well, looks a little bit weird (in my opinion); the chrome and copper
parts do not match that well, and the Nixie tubes are not that
incorporated in the overall design...

Anyway, I built something in Steampunk look myself, see the pictures
attached. I was fortunate since a lot of fitting parts have 18mm
dimensions which works almost perfectly with IN-14 Nixie tubes. An
article on the project is still in the writing, I will share the link
with you, in case anyone is interested.

Best wishes
Jens
distograph_1.jpg
distograph_2.jpg

threeneurons

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Jan 26, 2014, 1:33:34 PM1/26/14
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Not the prettiest clock I've seen. A lot of member's, here, have done a lot better. And many of those clocks could be considered "steampunk" too, style-wise. He's got some "brass" ones, submitting it to Kickstarter. If there's a viewer comment section, maybe we should add a link to better looking nixie clocks.

Nothing wrong with wood. As long as the maximum amount of power that can come into the case (if dead shorted), is not enough to ignite any flammable parts. Usually, old style wallcubes can't deliver that kind of power. Straight 120VAC (or 220VAC) coming in, can easily deliver enough juice. That's why its been pretty standard to have low voltage entering the case, and boosting it with a switcher, to run the nixies. One of my old job functions was to ensure, the companies products, was compliant to FCC and UL standards. If it was powered from a wallcube, it was easy. Just buy UL approved wallcubes, and I was done. At least for the UL safety part.

Tidak Ada

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Jan 26, 2014, 3:47:19 PM1/26/14
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Old radio and TV cabinets where also made of wood, but I never heard they did frequently (if ever) burst in fire... And Mains power came inside directly from the wall pug.
 
eric

From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On Behalf Of threeneurons
Sent: zondag 26 januari 2014 19:34
To: neoni...@googlegroups.com
Subject: [neonixie-l] Re: Steampunk

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Charles MacDonald

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Jan 26, 2014, 8:50:37 PM1/26/14
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On 14-01-26 03:47 PM, Tidak Ada wrote:
> Old radio and TV cabinets where also made of wood, but I never heard
> they did frequently (if ever) burst in fire... And Mains power came
> inside directly from the wall pug.

It is all in the design. Most wood cabinet radios have a metal chassis
inside which would trap flames. It was not unusual to have a piece of
Asbestos Paper under the chassis (try doing that these days!)

Fuses and fusible links can take the risk way down. Consumer units with
power transformers often have the fusible link inside the transformer -
over draw current and the transformer pops open from a link buried
somewhere in the primary winding.

--
Charles MacDonald Stittsville Ontario
cm...@zeusprune.ca Just Beyond the Fringe
http://Charles.MacDonald.org/tubes
No Microsoft Products were used in sending this e-mail.

threeneurons

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Jan 27, 2014, 1:19:24 PM1/27/14
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Yes, in the old days, with old radios and TVs, there was a metal chassis, housing the electronics. Then that chassis was inside the wooden case. Also a few had asbestos liners. About 20 years ago, I was corresponding with UL, about a several different safety standards, applicable to consumer electronics. UL replied that any could be used, and that they were just chronological refinements of the prior standard. The older ones would eventually be phased out. The point being, that what was considered safe for an old tube radio, won't pass by today's standard.

I'm also a second hand witness to a piece of relatively modern electronics (90's vintage stereo) catching fire, and burning down the house, of one of my friend's girlfriend. It had a plastic case. A short is a rare occurrence, but it does happen, and there can be enough energy to ignite stuff. Safety features, such as fuses, and decent connectors, can greatly reduce the probability, but nothing in this world is absolute. I also have been a first hand witness to power cords igniting after a short occurred. Fortunately, they, in turn, did not ignite anything else.

A wallcube, if shorted, will heat up, but don't usually pass enough power to cause ignition. They usually, just die quietly, by opening up.

petehand

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Mar 30, 2014, 6:46:16 PM3/30/14
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LOL, there's no accounting for taste. He raised nearly $20k, and he was only asking for $6k. What I want to know is, who the hell are these people with the money to throw in $600 or more? Two backers over $1800? Ye gods. Clearly, putting something on Kickstarter gets the attention of a whole new set of people we don't normally reach. I WANT TO KNOW WHO THESE PEOPLE ARE. Heck, for $800 (total pledges divided by the number of clocks he has to deliver) I'll put some old wood and brass tat on my stuff, and I'll even use nixies with actual real 5s.

Terry S

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Dec 26, 2014, 5:02:04 PM12/26/14
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The subject IN-18 in my Nixichron has degraded now to where only the top 1/4 of the digits are lighting.

Does anyone have a well-weathered IN-18 for sale? I prefer not to install a new tube.

Terry


On Wednesday, January 22, 2014 7:19:07 AM UTC-6, Terry S wrote:
One of the IN-18s in my Nixichron has started to fail. I don't know if it's cathode poisoning or some other failure mode.
 
In the 10's hours position, several of the digits are not lighting completely, they are dark toward the bottom of the tube, probably the bottom 1/3 of the numeral.
 
This happened rather suddenly, or at least I only noticed it recently. The "1" digit is fine, and that's what is lit most of the time. The other digits only come into play during display of the GPS coordinates every 1/4 hour. As they scroll across the clock, I can see the bad digits.
 
Has anyone seen this particulat failure mode in an IN-18? Bottom of some digits failing to glow?
 
I do have a couple spare tubes, but they have no hours on them. I'll try one to be certain it's just the tube. But I'd actually like to find a used tube, something with several years worth of use on it, so the brightness will be a better match.
 
Terry

Jeff Walton

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Feb 21, 2015, 9:54:54 PM2/21/15
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Regarding your concern about the wooden housing:

I had an old nixie design that I did in college in the 1970 timeframe.  It used voltage doubler circuitry for the nixies and housed a filament transformer for the main power supply, which were all mounted inside the housing.  My old design with point to point wiring and discrete devices is dark ages compared to current designs.  That clock ran perfectly for over thirty years with a wooden and plexiglass case and was no problem - until 2005 when the voltage doubler shorted and caught fire.  It had far more power available inside the housing when things went wrong.

I think that the designs from present day with the external power supply (and limited energy) are quite safe to run with wooden enclosures.  The power supplies are quite safe and if there was a problem with something, it would most likely not be with the clock itself.  

Charles MacDonald

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Feb 21, 2015, 11:01:03 PM2/21/15
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On 15-02-21 09:54 PM, Jeff Walton wrote:
> Regarding your concern about the wooden housing:
>
> That clock ran perfectly for
> over thirty years with a wooden and plexiglass case and was no problem -
> until 2005 when the voltage doubler shorted and caught fire. It had far
> more power available inside the housing when things went wrong.

Back in that time period I worked in a computer store and we sold the
"North Star Horizon" computer. It came in an optional wooden case. in
order to sell it here in Ontario Canada we had to get the local power
authority to approve it. The inspector would not let us sell it until
we lined the inside of the case with aluminum auto-body tape in the
vicinity of the transformer and main capacitors (brute force 8V & 16V
DC supply for an S-100 Style computer) The unit was otherwise
conservatively designed and well fused.

Jeff Walton

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Feb 21, 2015, 11:21:24 PM2/21/15
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In hindsight, if I had fused the voltage doubler separately from the main transformer, I might have escaped without much damage.  I'm guessing that my high voltage caps failed (after 30+ years of operation) and when they shorted, it produced enough heat to ignite the plexiglass.  Too bad there was no current limiting...   Fortunately, the clock was sitting on a stone countertop and prevented the damage from spreading.  The wood was so dry after 20 years that it was totally consumed and we just ended up with smoke damage and a mass of melted parts.  The nixies all shattered with the heat.  

I'm not sure that aluminum tape would withstand the kind of failure that I had.  :(     I do feel quite secure with the current wall block power supplies and the HV modules for driving the nixies that are seen in modern designs.

We learn from our mistakes!

Matt

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Feb 22, 2015, 12:03:44 AM2/22/15
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True. A *good* (and I stress good) switched mode power supply will become a constant current power supply when you exceed its
capacity. So if you short a 12 volt, 2 amp power supply, you will get no more than 2ish amps. If the UL or CE listing is accurate,
the power supply may get warm, but that should not be a problem. So to be safe, buy a switched mode power supply that can deliver
no more than the amperage that you need. That way, if something shorts in the clock, that is all the power it is going to get, which
is hopefully not enough to start a fire. To be sure, you may want to test this.

Unfortunately, there are many power supplies on the market that are unsafe for various reasons. Make sure to get one from a
reputable source, or have the power supply properly examined. Here are some articles and videos about unsafe power supplies:

http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html

https://www.youtube.com/watch?v=wi-b9k-0KfE

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

http://hackaday.com/2012/10/10/raspberry-pi-foundation-looks-a-counterfeit-apple-power-supplies/

https://www.youtube.com/watch?v=q9wKjZXDPWI&t=9m39s (USB power supply begins 9:39 in, ends at 17:52)

Also, poorly designed power supplies can add noise to your A/C line or RF interference for nearby devices. Here is one power supply
that mostly works, but poor power filtering prevents a specific device from working (while other devices work fine):
https://www.youtube.com/watch?v=8wkoxZw53Sk

This video explains how a simple switched mode power supply works:
https://www.youtube.com/watch?v=bmtW_oA1fRo

Jan Rychter

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Feb 23, 2015, 4:42:27 AM2/23/15
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I will second what others have already said here: I have a clock in a wooden (laser-cut plywood) enclosure, but:

* my HV PSU (http://jan.rychter.com/high-voltage-power-supply-for-nixie-tube-projects) has current limiting, so most faults in the HV section are handled gracefully,
* the whole unit is powered from a 12V/500mA brick.

I considered the safety issues, but then determined that it is *really* difficult to start a fire with 6W of power. And with most supplies having overcurrent protection you’d have to draw exactly 6W, a short would just trigger the protection and all you’d get would be the power supply turning on and off periodically.

So, assuming that your wall brick is reasonably safe (hint: if it’s very cheap, it likely isn’t safe), a wooden enclosure should be perfectly fine.

—J.
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