Testing Nixies

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John Snow

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Jan 30, 2020, 1:23:39 PM1/30/20
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I have some not-NOS nixies arriving, and they have flying leads instead of pins - what's the best way to test them prior to soldering them into place?

I've heard of using a plasma ball to ionise the gas to see if it's still sealed, but is there a gadget I can buy that clips onto the leads?

I'd like to check the digits all display before permanently soldering them into place

jb-electronics

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Jan 30, 2020, 1:27:41 PM1/30/20
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I like to use "clamp type test probes" for that purpose, they work quite well and are easier to deal with than alligator connectors.

Jens
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David Forbes

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Jan 30, 2020, 3:06:44 PM1/30/20
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My Nixie watches use B5870 tubes with flexible wire leads. I use tweezers to form them to the arrangement of the socket and plug them in. 
I recommend that you solder socket pins into one digit of your clock, and plug each tube into that socket before soldering it in. Better yet, build the clock with sockets of some sort. 
I could recommend ways of socketing the tubes if I knew the arrangement of the connection, i.e., OC board, perf board or what.


John Snow

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Jan 30, 2020, 3:33:11 PM1/30/20
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Ahh, this is for testing them as they arrive, then shelving them for future projects.

I saw Marcin Saj has a few testers, but they seem more for socket-pin tubes.

The knobs also don't have settings I can set it to for different tubes, or a display for the current voltage or current.

Nicholas Stock

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Jan 30, 2020, 3:49:26 PM1/30/20
to 'Greg P' via neonixie-l
John, 

Marcin used to sell (many years ago) a simple tester with flying leads that you could just attach to each cathode (and one for the anode) and it would automagically cycle around the digits or you could manually advance. 

All you really need is a 170V DC supply, suitable resistor (8K2 or thereabouts should do for testing purposes) and some leads with alligator clips....

Marcin still sells the 'pro' nixie tester...


However, I've had issues with the potentiometers failing on these (as have others), unless this problem has been solved.

A quick eBay search came up with..


(not my listing etc...).

Removing wired tubes is doable, but a PITA, so testing them beforehand is a good idea as you want to do. I've tested used IN14's and have yet to find a dud one, they're very very reliable tubes as far as I can tell. IN16's not so much, they're very troublesome tubes and fail a lot in my experience (as do IN2's...).

Wish you luck.

Cheers,

Nick



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alb.001 alb.001

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Jan 30, 2020, 7:41:06 PM1/30/20
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Cheap HV power supply method :

I built my own HV power supply for testing nixies.  Look around at second hand or thrift type stores for a single use camera with flash and manual film advance with a single or two AA batteries    Ones with a neon ready light are best  These have a 330 volt DC power supply for the flash.   You just cut off paper cover and pry the shell open  you will see the HV module and a large HV capacitor.  I replace the battery and turn on the flash - either a push button or slide switch.  If the neon glows in less than 30 second the HV works.  Turn off the flash and short the HV capacitor with am insulated screwdriver to prevent shocks  Remove the battery, and HV module and HV capacitor together.   Make a note of where the switch was attached and polarity of where the battery was attached.   I put these in a plastic box with battery holder, toggle switch and HV leads that go to red/black alligator clips  thru a 25 K resistor for current control   That's it, cost me about 5 dollars and is pocketable   I take it to all the hamfests and flea markets I go to and check any nixies before I buy.

Phamacy Phil 

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Richard Scales

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Jan 31, 2020, 12:08:54 AM1/31/20
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If you already have any nixie clock then I would pinch the 170V from there.
Make sure you run the anode via a suitable series resistor. Use the specifications for the device to calculate the appropriate value R = (supply volts-maintaining volts)/Cathode Current so a tube with maintaining volts of 140 and a cathode current of 2mA on a 170V supply needs a resistor of (170-140)/0.002 = 15K.
I then use a lead that has a female 'socket' which is actually used for breadboard/arduino type experiments to 'clip' on to the anode and another lead to which I have soldered a suitable thick piece of wire that acts as a probe.
I probe all other pins to test each digit.
All the usual warnings regarding 170V apply (I have had the occasional tingle in the fingers)
.. but if you don't already have a clock then as others have suggested,  A source of 170V must be found. There are plenty on eBay and AliExpress. I would recommend the NCH6100HV or NCH8200HV supplies from nixieclock.org (go for the genuine ones, there are dozens of fakes/clones). Tayloredge.com has a good range of HV modules at https://www.shop-tes.com/power-supply/ 
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