IN18 nixies

[exurbia]

I'm not sure whether this should come under the tube heading or not.
I've recently purchased a Nixie clock, the Nixies are IN18 they are russian and have 40mm high digits. They look rather impressive especially at night.
However i have a problem, some of the digits don't light properly.
Is this likely to be due to not enough drive or is it likely to be faulty tubes ?
Any help or suggestions would be much appreciated.
Cheers,
Peter.

 

[Sal Brisindi]

Well, it can be either problem you mentioned. Keep the clock plugged in for a while. Many times the partial lighting up of the cathodes will light up after a while.

Is this clock multiplexed or direct drive? I have built a bunch of nixie clocks and sometimes if I unplug them for a while the cathodes will take a while to work properly.

BTW, the IN-18's are nice tubes, I have about 30 of them.

Sal

 

[exurbia]

Hi Sal,
Thanks for the info, i have tried swapping the positions. The problem persists though and i now have a blue glow when the 1 lights up in two of the tubes. The clock has only been running for a couple of hours. I will use a bit of patience and not condemn the tubes out of hand. The clock is multiplexed, i have read on another site that direct drive is the best way to do it.
Peter.

 

[Colt45]

if it lights, but is.. kind of.. flickery, you can try bumping up the current a bit.

 

[quadtech]

Oh Oh! Take a deep breath, get a hold of yourself.
You may have a case of the Big C ....

http://www.tube-tester.com/sites/nixie/different/cathode poisoning/cathode-poisoning.htm

 

[exurbia]

Please Dr nixie, it can't be the big C mine are NOS , well the russians said they were.
I will have to build a Nixie tester like Dieters and try and cook them.
Thanks for all the glum tidings chaps

 

[quadtech]

BTW, the blue glow on IN18s is not unusual.
These tubes have a little bit of mercury in them, supposedly to prevent
cathode poisoning.

 

[h00hbt]

Hi

in worst place it could be cathode poisoning....

http://www.tube-tester.com/sites/nixie/different/cathode poisoning/cathode-poisoning.htm

cheers

/H

 

[fooeywuffle]

IN-18 tubes need good drivers like MPSA42 or any transistor that can handle at least 200 volts. Driving them with Russian 74141 ICs (K155ID1) can cause problems like those blue dots.