There is no "economical" model of a true oscilloscope. You might use some 
sort of audio card oscilloscope, but with such voltages you have to be very 
careful not to burn your PC - for example, use a voltage divider made of 
330k and 1k resistors (1k between GND and audio card input and 330k from 
audio card input to HV). This + some software (there are many audio card 
oscilloscope programs) should do the work for frequencies from audio range 
(20Hz-20kHz). I would also place two standard diodes in series, anode to 
audio input and cathode to ground - cheap and rather reliable way to 
produce a ~1,4V voltage limit.

Datasheet of IN-18 is hard to understand for me - I can read cyrillic, but 
barely understand language alone, so I make alot of assumptions from my 
native, also slavic language - but as far as I can read, allowed continous 
current is 4-7mA and average current for pulsed operation should be 2-4mA 
(specified for 50Hz pulses). If the current you have measured in your clock 
is a true average value of 5mA, then it is out of specs.

Can you check clock PSU voltage, anode resistor value, anode voltage drop 
(avg) and number of tubes used in clock? I bet doubling anode resistor 
value would fix the problem, as this starts looking like it isn't a problem 
with pulsed vs direct operation, but a design which is out of datasheet 
values for the tube. This will of course change the brightness, so you 
might want to use some other resistor - 30% bigger value than the original 
should be also okay.
Normally pulsed operation doesn't do anything bad to the tube, unless it is 
out of specs (too high or too low current*). Many smaller tubes in later 
designs were multiplexed, for example calculators - I've seen displays of 
one east german and one russian calculators and they both were multiplexed 
(Z574M and IN-14 tubes).

*I am not sure if too low current can hurt a nixie, but I believe it might 
increase sputtering - I have no data to back it up, it is just my strong 
feeling.

W dniu wtorek, 30 maja 2017 16:15:18 UTC+2 użytkownik Trumpeter napisał:
>
> Slot machine effect every 10min. Tubes were NOS but I wonder if I got a 
> bad batch. I guess I should buy a scope, any reccomendations for an 
> economical model that will get the job done?

-- 
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 [email protected].
To post to this group, send an email to [email protected].
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/0e39db9b-b7f3-4370-8f70-0c22c72d5981%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Reply via email to