Stuck with a stuck dekatron

[Paolo Cravero]

Hello.
I am stuck with a stubborn WE-6167 dekatron (http://www.tube-tester.com/sites/nixie/dat_arch/6167.pdf seems to be the only document available).

The tube is NIB made in 1958. I understand it is a single guide dekatron, and the stepping cathodes are split in two groups 1-5 and 6-10.

I built the circuit as per Mike's diagram (http://www.tube-tester.com/sites/nixie/dat_arch/6167.pdf) and it span correctly. I let it run for few minutes and then it got stuck at K10. Through the glass I can see that it attempts to jump ahead, but the main glow stays on K10. Fiddling with wires I could get it have one round up to K10. The more it runs the more it gets stickier. The relaxation oscillator never stops.

I suspected some resistor overheating or changing value, but even after hours of power-off, it doesn't go beyond K10. Or it simply powers up at K10 and doesn't step over, while it does visually try to jump.

Voltages are 450V/225V (input at 12V is 220 mA). Anode current is 1 mA (I increased the anode resistor to 250k) while the current coming out of the active cathode(s) is 1.5 mA. Stepping goes from 200V down to 2V (green trace). Anode voltage (450 V) doesn't sag noticeably and inductor+IRF get barely warm. The yellow trace in the oscilloscope shot is  measured at the "+58V" point (yes, I did try to move that voltage up and down with no difference).


Then I opened a second new in box WE-6167. It ran correctly for a minute, perhaps 100 rounds, then it started hiccupping (I think between K5 and K6) and finally got stuck on K10 with the flicker towards the stepping cathode.

It must be something with these tubes. Does anyone remember a similar behaviour in never used dekatrons? I've read of deks needing a high current "preparation", but not of them failing after a good start. I would like to get out of the K10 position!

Thanks,

Paolo

[Dekatron42]

I see this a lot in some Dekatron types/brands that have been stored for a long time, some brands have fared better while being stored compared to others and some very´seldom experience this problem. I usually just increase the current either by raising the Anode voltage or decreasing the Anode resistor and then let them sit for a few hours up to a day or so and they usually start to run again past the sticky point. In those that you can reverse the rotation I sometimes switch the direction back and forth so I know that they run well in both directions.

/Martin

[Tidak Ada]

Hi all,

 

 

Unfortunately no further info here.

A guess is it a kind of cathode poisoning??

 

Did you already contact the TCA [ tubecollecto...@groups.io ]. They are based in the USA, so the chance is greater there is info to find.

 

I have the same problem with a rare Pressler N3 dekatron. Anybody her who can help me on data and applications?

The Pressler N3 is a WW-II tube with a 8 pin ‘German Stahlrohren’ base.

I have no data and therefore no clue how to drive the tube.

Trying to light up the tube with a blue-ray machine did not work

 

Cheers,

Eric

 

Van: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] Namens Dekatron42
Verzonden: woensdag 23 februari 2022 10:09
Aan: neonixie-l
Onderwerp: [neonixie-l] Re: Stuck with a stuck dekatron

 

[Dekatron42]

Regarding the Pressler N3, I hope you have seen the datasheet here: http://lampes-et-tubes.info/cd/N3.pdf

Out of the bunch that I own of these only a few are running (and maybe half are out-gassed and some have mechanical faults like loose welds and pins rumbling around inside the envelope) with the original circuit.

/Martin

[Tidak Ada]

Hi Martin,

 

No, I was not aware, despite Giorgio is a friend of me….

 

Thanks for your tip and  experience

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[gregebert]

When I had initial problems with my A101, I increased the steering voltage by using a larger cathode resistor and it's worked flawlessly ever since. I couldn't tell from posted scope trace what the measurement was. Also, you want to have overlapping waveforms, with no dead-time, to ensure the gas is always ionized. Again, with my A101 as an example, I have 3 driver transistors, A, B, and C where "A" is all 10 cathodes tied together, and B & C are the steering cathodes. The 6-stage sequence is A-> AB ->B ->BC -> C -> CA -> A (repeat). To reverse the direction, swap the sequencing of B &C.

[Jon]

The sticking on K10 specifically is a peculiarity of the 6167 in my experience. I believe it's distinct from the sleeping sickness effect that Martin describes as that is essentially random in which cathodes are affected (and as he says, working the tube, possibly at elevated current, in both directions where possible, is usually an effective cure).

I mostly saw K10 sticking when I was exploring a circuit that makes use of the unique auxiliary anode connection (pin 5) which of course lies adjacent to K10. What seems to be happening was that when the glow gets to K10 there is current flow from both the main anode and auxiliary anode. The next transfer pulse moves the glow onto the transfer electrode, but when it terminates the auxiliary anode-K10 gap is still sufficiently primed so that the glow mostly steps back to K10 rather than forward to K1. I was able to mitigate this by reducing the auxiliary anode potential below what I'd originally understood it needed to be from the datasheet (the datasheet is really opaque on this point), and also by lengthening the transfer pulse to allow more deionisation time.

However, if I understand Paolo's post, he's using Mike Moorrees's circuit (https://threeneurons.files.wordpress.com/2011/09/we6167ckt.gif) which leaves the auxiliary anode disconnected. When I ran 6167s in this configuration they were generally much more reliable in not sticking on K10, though I was using rather different circuit conditions:

• Va = +400V with respect to main cathodes
• Transfer pulses 60V amplitude from a resting bias +30V with respect to main cathodes
• Anode current 1.3mA

Paolo, can you confirm you have indeed left pin 5 unconnected? If so, given that the sticking effect seems to be increasing with tube use, I wonder if we're seeing the floating auxiliary anode gradually charging up and eventually reaching a potential which is disrupting the stepping operation. Maybe use a potentiometer or potential divider to pin the auxiliary anode at some moderate voltage positive to the main cathodes (say +100V as a starting point) and see if that helps?

They're funky tubes...

Jon.

[Jon]

To Eric's question on the N3...

These are also rather tricky tubes. My experience is similar to Martin's - unfortunately many examples of N3 are non-functional in that they won't even strike a glow - outgassed or similar. I fear that if you can't raise a glow with a violet ray unit or plasma globe then yours may be dead :(

But if you do find a working N3 or N4, then the conditions below work for me:

• Va = +350V with respect to main cathodes
• Transfer pulses 30V amplitude from a resting bias +15V with respect to main cathodes
• Anode current 1.6mA (82K anode resistor, 8K2 cathode resistors)

It's quite an unusual design with relatively low anode and transfer electrode voltages. If the anode voltage or current is too high, it's easy to get multiple cathodes glowing instead of just one which can mess up the stepping.

Jon.

[Tidak Ada]

Thanks John, that is useful information!

Yes, you confirm my fear. Fortunately I bought the tube as am collecting item,

         Eric

Verstuurd vanaf mijn iPhone

Op 23 feb. 2022 om 23:21 heeft Jon <deka...@nomotron.com> het volgende geschreven:

To Eric's question on the N3...

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[Dekatron42]

I forgot to mention that when I am "un-sticking" a Dekatron I just connect all cathodes together so they don't have differing potentials, with or without one common cathode resistor for all cathodes.

/Martin

[Paolo Cravero]

On Wed, Feb 23, 2022 at 11:04 PM Jon <deka...@nomotron.com> wrote:

Thanks to Martin, Eric and Jon for their answers.

However, if I understand Paolo's post, he's using Mike Moorrees's circuit (https://threeneurons.files.wordpress.com/2011/09/we6167ckt.gif) which leaves the auxiliary anode disconnected. When I ran 6167s in this configuration they were generally much more reliable in not sticking on K10, though I was using rather different circuit conditions:

• Va = +400V with respect to main cathodes
• Transfer pulses 60V amplitude from a resting bias +30V with respect to main cathodes
• Anode current 1.3mA

Paolo, can you confirm you have indeed left pin 5 unconnected?

Yes, I confirm I used that circuit from A to Z. Then I varied the bias voltage and/or anode current (up to 1.5 mA), but both auxiliary anode and reset were floating.

I will rebuild the test setup with an external power supply that can provide more current, as the LM393 booster is struggling with 2 mA at 400+ V, and use zeners to derive the bias. According to Jon's list, a starting point for voltages should be:

• main cathodes +30V,
• transfer pulses from +60V to 0V,
• main anode at +430V;
• K10 current at 2mA which brings
  
• auxiliary anode at +115V (datasheet PDF, 4th page)
  

I wish we knew which device used W.E. 6167 dekatrons so that we could have a look at the diagram...

Paolo

[mjrippe]

>I wish we knew which device used W.E. 6167 dekatrons so that we could have a look at the diagram...

Hi Paolo,

I did some research on these tubes about a decade ago.  There was not much info available, perhaps more to be found now.  Here is the one use case I did find - good luck finding out more!

From AAFM Vol. 6, No. 1  March, 1998  (Association of Air Force Missileers)

Origin of the Ground Guidance System The Titan I
guidance system was developed by Bell Telephone Laboratories
(BTL). It started as a WW II shipboard radar,
built by Western Electric Company, and grew to include
an analog guidance computer for guiding early experimental
rockets and the Nike-series missiles. The analog
computer used two large motor-driven oil-filled sinecosine
potentiometers and lots of op amps to generate
the guidance equation. A bank of ten turn
potentiometers provided variables to the guidance
equation, so that roll-over and changes in acceleration
could be programmed. The whole thing was sequenced
by some little Western Electric 6167 ten-step pixie tubes.
It used electron tubes, for this was before the proliferation
of the transistor, and mean time between failures was
acceptable for that era, but short.

Yours,

Mike

[Dekatron42]

There's another nice datasheet with a lot of information here: https://static1.squarespace.com/static/5f0983034219c6086e8100ac/t/5f4566168ede3e5edceb395e/1598383652854/439A.pdf

@mjrippe: If my mind doesn't play tricks on me I think I got some Telephone related patents from you after you mentioned them in this thread where I asked for help to get my 6167/WE439A to run: https://groups.google.com/g/neonixie-l/c/xn7QcomQZSg

/Martin

[mjrippe]

Wow, Martin!  Your memory is much better than mine ;)  I just had another look through my old files and the patents were in my Nixie folder, not the Dekatron one.  I have uploaded a small collection to my DropBox:  https://www.dropbox.com/s/gtxboyvkna7j8dt/6167%20Docs.zip?dl=0

Yours,

Mike

[Paolo Cravero]

Thank you Mike for the Analog Guidance Computer hint. It seems someone has been documenting it/them online: that's a route to follow to locate a schematic diagram.

And Martin's 439A datasheet is very helpful too. At least it is complete.

I haven't made much progress, except that I even got the glow to stop in the "pick-up tabs". Also I have observed that the spinner stopped as room temperature decreased. Guides control voltage swings between +106V and -30V with respect to K1-K9 output cathodes, but even +106/-70V doesn't get a reliable spin. Next I will try to reduce the positive bias and to put a radiation source close to the tube, just in case it was doped with Kr-85 that would have very little activity left by now. I think that kind of doping was more important on tubes that needed a fast switch-on time while 439A/6167 was a slow dekatron.

Paolo

[Paolo Cravero]

Hello.

I still cannot get these WE6167 spin uniformly. I might have stray capacitances on the breadboard, but I won't invest in a spinner PCB with this huge doubt. I do have some findings and thoughts to share.

The 10 output cathodes can be used to control the glow of each dot since they do illuminate like a Nixie with a 200-230V anode voltage at 1-3 mA. Actually there are eleven cathodes as there is a normal - zero - control. It is cheating, I know, but it will then be able to visually spin counter-clockwise too! Also I will not need 400+ V and the same circuit can control a symbol Nixie. The drawback is that it will need a microcontroller.

While trying all sorts of modifications to the spinner circuit, I noticed that the most stubborn 6167 was made in 1955 (its K10 needs at least 225V to light up in "Nixie mode"!) while the rest were assembled in 1958. In the attached picture you can see how the 1955 tube in the middle has a shorter rounder dome. The dirt on the glass is a sticky leftover of a wax paper(?) that wrapped the tubes.

I might look through the glass for construction differences but I stored the 1955's 6167 away since .... it is mildly radioactive. On my Geiger-Muller counter sensitive to hard-beta and gamma the 1955's 6167 produces a 3x increase in CPM vs background while those from 1958 don't make a difference. Note that neither the glass bulb nor the box mention the content of radioactive material (nor the datasheet). Citing myself (Wed, Nov 4, 2020, 1:12 PM to neonixie-l) "Same goes for other 6140 except for one, much older from 12/52 marked 423A. Neither the box nor the glass carry any warning sign, but this tube hits >600 CPM vs 40 CPM background". Looks like that up to at least 1955 it was not required to declare the content of radioactive material inside vacuum tubes (and that W.E. was pretty generous on the amount used ;) IMVHO ).

Last but not least I forgot I had inserted in my eBay watchlist item #202784117971, a Western Electric burst timer. That's another device that might have been documented online.

Paolo

[Dekatron42]

Have you tried the last circuit in the datasheet above (https://static1.squarespace.com/static/5f0983034219c6086e8100ac/t/5f4566168ede3e5edceb395e/1598383652854/439A.pdf) which uses an RC-network on each cathode?

I've not tried this on a 6167 but on some other older types it is necessary to get them to run properly and I've also tested it on other types when I've had problem (or no data) getting them to run and in some cases I have succeeded to get them to run well enough that they later started to run in a normal circuit.

/Martin

[mjrippe]

Hi Paolo,

There are two envelope sizes for the 6167/439A.  I have not analyzed whether they are date-related or otherwise different.  There are also some tubes clearly Kr-85 marked, as you mentioned.  I don't recall what readings I had on my Geiger counter back when I tested them, but other tubes I own were more active.

I have made another DropBox file with photos of both 6167 and 439A tubes of all the types I had at the time.  There is even one specifically marked as NON-JAN.  Link is here: https://www.dropbox.com/s/1nl36d0y87k6qsg/WE%20Pix%20Archive.zip?dl=0   Be sure to turn down the volume on the .MOV file of a 439A spinning, unless you like heavy metal ;)

Yours,

Mike

[Ⓙⓞⓗⓝ Ⓢⓜⓞⓤⓣ]

A huge thank you to all those who have offered to send letters to my wife for me. I shall be writing to you all in due course. I shall see my son, who has procured the stationery for me, on Sunday. I can then start to organise things.

If there is anyone in the Middle East, or Far East. China, Japan etc. who could send out some letters for me, then that would be superb.

Now I have to sort out my clocks, nixies and VFDs and get those dispersed.

John S

[peter bunge]

John; hang onto those treasures.

Maybe reward a good friend by setting something aside that your son can deliver. Your family may like to keep a few items to remember you. After all this is part of you.

I have a friend in long term care who knows his collection of vacuum tubes are safe with his brother. It makes him happy.

I will help the brother sell them when the time is right. I would not like to take anything now.

I am 82 and this is the story of my life since Monday. It is great to have friends and people who care for you.

On Monday I was at Pembroke hospital (50km from here) to have skin cancer cut out of my head, it was a minor surgery that took 20 minutes. 

Tuesday morning was my wife Jan's turn to go in for an operation to remove a kidney stone, and I was to drive her to Pembroke for 8:15. 

About 3 am Tuesday I woke up with a pain in my lower gut and by 5 am the pain was so severe that Jan called the ambulance. I told her to call one of our friends to take her in (she was thinking of cancelling her surgery), The Deep River (where we live) hospital diagnosed me as having either a twisted bowel or appendicitis. I was rapidly put in another ambulance and sent to Pembroke for a Ct Scan.

By 10 am, after having the scan, I was diagnosed with appendicitis. The doctor offered two choices; treat with antibiotics and see if it worked over a few days, or removal. I said that while I was healthy it would be best to operate. If it returned when I was older I might not be as able to recover as fast. The doctor agreed and said that is what she recommended. She said she would shuffle her schedule and do it the same day.

Jan had been driven in by our friends Mike and Joyce, and the nurses kept each of us informed of the other's progress and updated Mike. By 4 pm Jan and I were on gurneys beside each other outside the operating room, her on her way out and me on the way in. The nurses had arranged to hold Jan there in recovery knowing we were concerned for each other. The nurses took great care of me and came by often through the night. and chatted if I was awake.

The doctor came by in the morning and, after some questions, said she could release me by noon if I felt OK. The nurses arranged for Mike and Jan to come up and wheel me down to the exit where I waited a few minutes while Mike brought the car around and we all, including Joyce who had to wait in the car, drove back to Deep River.

Our friend Brian had come by to get the keys Jan had left in our mailbox, and to clear the driveway of snow. But he found someone had cleared it already. We have nice neighbours.

It snowed again last night and Brian came by this morning (Thursday) and cleared the driveway with our blower. I think he just wanted to try it because his is not easy to use but I think Jan could use ours. 

So there is my story of great friends and neighbours and an excellent ambulance and hospital service in our area.

I am up walking about this morning and healing fast. It is still a bit painful to stand and sit but I'm not taking any of the pain meds prescribed, just a Naproxen every 12 hours to reduce inflammation.

John I am lucky and appreciate it and my friends, and all the ambulance staff, nurses and doctors that helped. I just wish you were so lucky. Stay cheerful and don't dwell on the bad things, Peter

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