u/EmotionalEnd1575

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?

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!

If I had a drawing for the Burroughs version I have misplaced it, but I did find one from ITT.

This would have been useful when I made a Kicad library package recently. The dims I read with a digital caliper have two errors, both in the location of the DP wires.

My first attempt was “off” a small amount, not a show stopper, but annoying nevertheless.

Dim ‘P’ is not equal to Dim ‘Q’, and

Dim ‘N’ I completely missed!

I’ll correct my library, and “spin” the PCB files.

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.

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!

My baseline range, when the eTon was new 204miles.

AUDI did a firmware update to release more usable battery capacity, and we got about 220miles (+7.8%)

A charging session after winter “storage” (not indoors) was a disappointing 187mi.

Was this the expectation after five years? Did we not use the best method, by leaving the battery at about 60% full for four months and no driving at all?

**What are other owners finding out?**

Today I drove about 80mi and immediately jumped on a public L3 (EA) charger.

The range at the end of charging was an amazing **226miles!!**

By the time I got home (2miles away) it settled at 216miles (with A/C on green)

*I’m delighted to have 200+ But will it hold?*

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 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,

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 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?

This orange plastic filter was part of a 1960s vintage Burroughs Nixie Display.

I took a PIX with and without it laying on top of an IN17 Six tube display.

Did it help? Looking for a way to make these little Nixies easier to read.

Comments welcome.

This build has twin neons for digit separators.

I’m wondering if these neons are bit too big to be next to the tiny IN17 top reading Nixies?

Should I look for smaller neons for this one?

Let me know your thoughts.

Probably need a “blue cut” optical filter here to knock down the UV from the mercury glow?

Any suggestions on what filter material to use?

I’ve seen red or orange tinted material used in some of the earlier Nixie display frames.

The iOS camera (most phone cameras?) pick up that bluish tint from raw glass Nixies.

To test the completed PCBs here’s a hand wired prototype circuit board.

The Nixie tubes are attached to their PCB, which is in turn plugged into this “motherboard” for testing.

There are support circuits on the motherboard including the three discrete high voltage switches that drive the Anodes for MUX, an RTC module for time data, a rotary encoder for manual digit selection, and a status LED bar graph. High voltages come from the HVPSU module shown in another post.

A Microchip/Atmel Atmega 328 MCU provides timing and control, and has the minimalistic hardware for uploading firmware during development and testing.

What do you think of this set up?

Continuing my experiments to compare different Nixie tube’s appearance I created some PCBs.

For the small tubes I set the tube spacing for a six digit array, with neon spacers between HH, MM, and SS pairs.

The three Nixe types that have been installed are:

Burroughs B5885 (side view)

Gazotron IN-16 (side view)

Gazotron IN-17 (top view)

The single driver IC and anode resistors are on the backside, due to limited PCB space.

Six tubes are MUX’d with three Anode high-side switches, on the mother board (not shown in this post)

Another PCB has been fabbed for six medium tubes, Gazotron IN8-2, and is being assembled.

This uses direct drive with three cathode driver ICs, on the PCB, each connected to a pair of tubes.

What do you think of these?

To power my various Nixie projects I created a HVPSU module.

Running from 12V DC it delivers a 180V Rail for the Anodes, a 60V Rail for the Nixie driver ICs, 5V for the RTC module and the MCU.

The build uses a mix of THT and SMT parts.

This is a hand assembly, using a Pizza oven for the mass soldering of SMT parts, which requires two passes starting with the parts on the backside.

For the first batch I used a syringe to “dot” solder paste and tweezers for pick and place.

What do you think?

Just completed a six digit Nixie clock tube testing fixture on a protoboard.

The goal is to have a way to power up and test different nixie tube types by swapping the plug-in PCB module that carries the tubes.

Although the idea was to just run through all numbers (cathodes) for testing, and possibly for “burn in” to repair any failed digit glow, adding an RTC made it into a functional clock.

These are Burroughs B5885 Nixies salvaged from a 1970s calculator (I think, I just got the hacked up PCB with the tubes still attached)

I made a similar PCB for Russian Nixies, one for IN-16 side view and another for IN-17 top view types.

What do you think?

I can post more PIX or details if there’s interest.

Twice a year our EV club hosts a public EV event.

Manufacturers, dealers, club members, are welcome to show off their EVs.

We let visitors test drive dealer vehicles, take a ride in an EV Tractor-Trailer or an antique (1920s) vintage battery electric vehicle.

This year we also had a lot of eBikes open for test rides.

My AUDI eTron drew a lots of admirers, too.

Thanks again to Daimler for letting us use their campus parking area.