Simplified circuit for driving a Russian A-201 Polyatron!

[Dekatron42]

Hi All,

I have now put considerable time into searching for more information on the Russian A-201 Polyatron made by Plasma Labs. I found a few books with the help of friends and also put several hundreds of hours into googling and visiting libraries to try to find more information, buying books and also communicating in Russian with the help of Google Translate. I also found some information on the Russian Radiokot.ru forum which helped me piece things together - but the trickiest thing to overcome was my little knowledge in electronics! I've studied electronics 20 or so years ago but not much stuck, my mind is like a teflon pan, some things just doesn't stick. But since my mind works beatifully when it comes to pictures I could stitch it all together by using all of the photos and images that I saw. And by being stubborn in trying to learn electronics all over again I managed to put it all together into a working circuit. I got very good help from collegues at work and also from LTSpice which has been used extensively. Some of you will probably say that it is easy to fit it all together, and I am happy for you, but I am even more happy that I conquered this and got it to work.

I found a Russian patent that descirbed a simplified way of driving the A-201 by using just one PNP transistor and an integrating R-C network much like ordinary dekatrons are driven with just one pulse. The patent is included here, with an English translation made by Google Translate. The patent number is: SU609215.

The circuit is made simpler by changing the polarity so that the anode of the nixie is connected to the common ground and the cathode of the Polyatron is connected to the negative connection of the 450V power supply, the positive electrode of the 450V power supply is connected to the common ground. The circuit shown over at Radiokot.ru was missing some parts as the PCB it was reverse engineered from was cut of by a saw so part of the PCB was missing. However with the help of the russian books I found and the patent I could piece it all together and get a working circuit. There is a need for a -160V power line in the circuit which the Russian design simply took from a zener diode connected to the negative electrode of the 450V power supply. This -160V signal is used both for biasing the PNP transistor and also for feeding the SET/RESET circuit used when setting/resetting the Polyatron into any position. This -160V signal is applied to the auxilliary anodes via a current limiting resistor and the ignites that auxilliary anode, moving the glow to this auxilliary anode.

With the circuit shown I could get the Polyatron to run up to some 4.5KHz with a Nixie connected and without the nixie it ran up to 10KHz. I made a movie of it running at some different speeds up to full speed where it failed and I then turned down the frequency some to get it started again: http://youtu.be/J4mH9b4SoJU

Cheers,

Martin

[Jon]

This is serious historical detective work - amazing stuff Martin!

Cheers,

Jon.

[Dekatron42]

Thanks Jon!

I'm actually quite proud of myself (which I guess could be read between the lines above, without much effort from the reader!). I couldn't have made it at all without help from you and other friends and people who published tidbits here and there, like "Myxomop" over at Radiokot.ru who showed his sawn off PCB! His reverse engineered circuit diagram contained at least one error which took me some time to realise, I didn't spot it until I made a try at reverse engineering the PCB myself, fortunately he had shown the reverse side of the PCB too!

Cheers,

Martin

[threeneurons]

Nice work !

I gotta get my hands on one of those, one of these days !

[Dekatron42]

Thanks!

You just have to sell two of your DK23's to buy one at the current going price on Ebay! ;)

/Martin

[Jon]

Just mad pricing on both of those types at the moment. Crazy!

Jon.

[Spencer W]

It was working correctly, the back shield was lit up but now the light is only on the legs. 

I was applying the positive voltage to the left leg (the u shaped part inside) and ground to the back shield. 

Sorry , I have no idea the proper names on those parts ;)

Sent from my iPhone

On Mar 1, 2014, at 2:25 PM, Jon <deka...@nomotron.com> wrote:

Just mad pricing on both of those types at the moment. Crazy!

Jon.

--
You received this message because you are subscribed to the Google Groups "neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+...@googlegroups.com.
To post to this group, send an email to neoni...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/b4b20e9d-35db-48d2-8fb4-6f73dd6083ac%40googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.