r/nixie

When firing up the IN8-2 Six PCB it didn’t go well at all!

This is a classic problem, somehow the Anode and a Cathode connection were swapped.

My error started at reading the data sheet, which is written in Russian.

The pinout was viewed “on bottom” and in my world all components are viewed “on top”.

How to fix?

The six tubes had to come off the PCB. The PTH for all had to be cleared of solder. I found that manipulating the Anode wire and rotating the rest one space would work.

But… The Cathodes for Four and DP were now swapped, so clipping the DP wire (not used) and a bodge wire fixed the hardware.

It also required new mapping for the firmware table that directs which cathode should light.

Surely, I’m not the first to make this mistake?

1. RCh3-07-0001 (РЧ3-07-0001) Programmable 12-digit reciprocal frequency counter

2. Ch7-15 (Ч7-15) Synchronometer

3. Ch3-54 (Ч3-54) Frequency counter

4. Ch7-3 (Ч7-3) Lab clock

5. PSO2-08 (ПСО2-08) Dekatron decimal counter

6. G4-164 (Г4-164) High frequency generator

7. V7-22A (В7-22А) Multimeter

Just powered up a new build, and after some wrangling with it, the Nixies light up!

The six digits and drivers are on a PCB that I designed and fabbed last month.

To power it up I built a protoboard around an ESP32 module.

Still have work to do on the animated Colon neons.

The timekeeper for this one is a GPS module, which needs an external antenna when in my basement lab (not too surprising)

Still exploring how the GPS time signal will be incorporated, as there’s also a battery backed RTC on this one.

Comments and suggestions welcome!

What is this pin used, what does i.c. stands for?

Returning to issue of an optical filter to improve contrast, there are/were some factory supplied Red filtered Nixies.

This is an RFT Z573M type.

Again, trying to get a digital PIX to look like these do to the naked eye is a challenge.

I’ll do a side by side test, if I can locate two of the same type number and one with the red coating and one without.

Just found these Nixie tube clocks on Etsy and wow… probably the coolest clocks I’ve seen 😅

The wood and brass details look amazing.
It somehow feels both retro and futuristic at the same time.

Now I kinda want one for my desk setup.

Anyone here has one?

Finished up an IN-18 Nixie clock with weather display in a burl wood and 3D printed case with copper baseplate for a friend of mine.

IN-18 Nixie tubes from 1982, burl wood case, 3D printed chassis, live zip code based weather indicator back/below lights, copper baseplate.

The weather part is blue when cold, red when hot, green when 70 degrees, blue flashes when rainy, white flashes when snowy, etc.

Some progress PIX while building a Nixie display PCB using six NL5870 tubes.

The PCB was designed for B5855 tubes that are almost identical (the pinouts are slightly different, so one redundant Anode wire has to be snipped off)

The SMT parts are soldered first, using a “Pizza Oven” (not used for food)

Without a stencil the solder paste was applied by syringe, and is very hard to get the volume just right.

The cathode driver IC is a challenging 0.65mm pitch TSSOP28 package.

THT parts are hand soldered, and finally the glass tubes and neons. Aligning the Nixie pins is quite difficult!

The nice thing about birthday’s as adults is picking your own present!

Sure, you will loose the element of surprise, but let’s face it, isn’t a “non-surprise” gift, even to yourself, still worth a smile?

My big day is next week, or a week after that, who knows? Who cares?

So forgive me for opening this one a little early.

I’m thinking Nixie clock, right?

I ordered the clock board on AliExpress. The clock has such a gorgeous lamp; any lamp lover should have one!

When looking for tiny colon neon bulbs a few years ago I found these 3mm bulbs. They're incredibly tiny and ideal for use with IN-2, IN-16, IN-17 tubes. The picture shows an IN-17 tube, a common 5mm (5x13) bulb and the 3mm (3x10) bulb. It's amazing the can produce them this small.

Should you ever need them, search for 3mm neon bulb on eBay or Ali.

Another BAD day here, second IN-17 to fail. The first was several weeks ago, and these two were in completely different builds.

In each case one digit (cathode) fails to light, but the other nine work properly.

It’s a MUX drive scheme and three tubes are in parallel, but only one of the three fails.

It is not the solder or lead out wire, and on closer inspection under the microscope it is an internal short. In both dead tubes the same cathode (digit six) is the only failure.

The short is about 1K5 between the cathode and anode leads.

The root cause is an insulation break where the internal connection ribbon passes over a mica insulator and over the edge of the metal frame. The frame connects to the anode.

I have not cut (opened) the tubes, in fact one is still soldered to the PCB, and will take some effort to remove and install a replacement without further damage.

Anyone else have a Nixie horror story, or any insight into this problem?

I've recently setup a few clocks in my office at work. From left to right, IN-8 fine mesh, IN-12, IN-16 (nixiediy kit), and IN-14. In thinking about building an IN-18 next, but may go for an inixie clock instead.

I keep these on my bench as a reminder that Nixies are glass and fragile.

Turns out that the non-lighting IN-17, that might have had an internal short, was a red herring.

On closer inspection I found that all three Nixies on the same bus had a missing “six”.

There was an intermittent failed soldering on the driver IC. Hard to notice this without using a microscope!

I still have the original IN-17 with a “Six” short.

To check Nixie operation I can run a test that uses the rotary encoder to scan through digits and also select which Nixie to drive.

A couple of hours lost today, but a good learning experience.

Comments Welcome,

I’ve hunted down smaller neon bulbs, to improve the appearance of Colon markers between Nixie tubes (small IN-17 top view type)

The smallest ones look much better than the previous effort.

The generic name for all of these neon bulbs is “NE-2”, although they vary quite a bit in size of the glass and length of the electrodes.

There is probably variation in the gas fill pressure, and mixture (doubtful it is pure neon gas)

I didn’t keep very good records of when and where I got these, although at least one was in a Mouser labeled bag.

Stating the obvious, running any neon bulb from DC is allowed, but doing so only one electrode (the negative or cathode) will glow.

There’s a workaround for this, that lights both electrodes, which I’ll share later.

Do you like the new (small) or old type neon bulb colons in this application?