Were these currents measured by scope waveform?
There is a big difference between a 1mA current at 100% duty cycle and, for
example, 5mA pulses @ a 20% duty cycle, or 8mA pulses @ a 10% duty cycle. Any
of these examples will change the effective brightness. The 1mA example will
likely cause cathode poisoning. A typical multi meter doesn't give an accurate
picture of the actual voltage and current of pulsed waveforms.
If you run the clock (long term) at full brightness, do you experience any
poisoning on the seconds or minutes tubes? Those two tubes are the best to
judge because all cathodes are exercised equally.
Cathode poisoning prevention cycles require full brightness cycling to be
effective and in many clocks are disabled during dimmed operation. The
brightness would be an annoyance in a dark room.
Check to see if your voltage at the anode is within spec and that your power
supply is providing full rated power under all conditions. A faulty power
supply can also "under-drive" the tubes and that will prevent the "cleaning"
effect that occurs with normal operation.
What kind of clock are you running? In a good clock design, your tubes should
"heal" (after awhile) if run at full brightness.
Jeff
-------- Original message --------
From: Trumpeter <[email protected]>
Date: 5/13/17 11:53 PM (GMT-06:00)
To: neonixie-l <[email protected]>
Subject: Re: [neonixie-l] Re: In18 displaying cathode poisoning after 1000hrs
or less.
Hi folks,
I have had some time to troubleshoot my clock. I found that when running in
night mode the tubes are supplied with around 1 mA, and when in day mode are
supplied 5 mA. These readings are taken between the annode resistor (10k) and
annode. My understanding is the tubes should receive between 4-6 mA. Could
the lower night mode current be causing the problems with positioning? I did
confirm the tubes are suffering poisioning because I have been able to
rejuvenate them by running the offending digits at 10 mA for between 30 min to
3 hours. I'm thinking of running the clock on day mode continuously to see if
the tubes begin to heal themselves. Thoughts? Anything else I should be
looking at?
--
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/9a75cb3d-6e91-4fcc-9827-a275dda57385%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
--
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/codmsbu25ipm2pphtfacnm4n.1494740856171%40email.android.com.
For more options, visit https://groups.google.com/d/optout.
