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 <[email protected]> het volgende
> geschreven:
>
> 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.
>
>
>> On Wednesday, February 23, 2022 at 10:04:53 PM UTC Jon wrote:
>> 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.
>>
>>
>>> On Wednesday, February 23, 2022 at 8:37:58 AM UTC Paolo Cravero wrote:
>>> 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
>>>
>
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