How much current are you using in a directly driven tube? I’ve had the same issue with the pins lighting up with as little as 1mA on the Z570M tubes.
On Monday, October 30, 2023 at 10:31:57 AM UTC-4 Craig Garnett wrote: > Increasing the HT gave me 10mA and looks pretty good but is this an issue > in the photo? > It only occurs in the multiplexed tube. > > Thanks > Craig > > On Friday, 27 October 2023 at 18:13:19 UTC+1 Craig Garnett wrote: > >> Thanks gregebert, >> I'll have a play with the HT voltage and report back. >> >> Craig >> >> On Friday, 27 October 2023 at 16:33:12 UTC+1 gregebert wrote: >> >>> You can run nixie tubes at much higher voltages if you wish, it does no >>> harm as long as you increase the series resistor to keep the current within >>> spec. For example, my first nixie clock runs the B5092 tubes from a +340V >>> supply, and I used a larger resistor (75K I think) to get the optimal 2.2mA >>> current. Running at higher voltage gives you more design margin, but it >>> does waste more energy as heat. Generally my HV supplies run between +200 >>> and +220VDC; seems like every clock I make ends-up with a different power >>> supply design. So far, I've designed and built nixie clocks with B5092, >>> B6091, B7971, IN-18, and RZ568m tubes. >>> >>> I would bump your supply up to +200V, and adjust the resistor to get 8mA >>> of peak current (6:1 multiplexing). That will give plenty of voltage margin >>> as the tubes age. From the photo, 8mA looks nice. I recommend that you >>> view your tube as you vary the supply voltage to get currents between 5mA >>> and 12mA just so you can see the effect of current on brightness. You >>> should see that once the tube is lit "normally", increasing the current >>> doesn't make as much of a change visually. >>> >>> I dont run my tubes multiplexed for a variety of reasons. >>> >>> On Friday, October 27, 2023 at 1:38:06 AM UTC-7 Craig Garnett wrote: >>> >>>> Thanks gregebert >>>> >>>> My HT is a 12V module and is adjustable but the tube spec says 170V so >>>> I left it at that. >>>> Are you saying that it's safe to increase the HT to get maybe 10mA? >>>> >>>> Craig >>>> >>>> On Friday, 27 October 2023 at 05:06:34 UTC+1 gregebert wrote: >>>> >>>>> My concern is that over time as the tubes age your HV supply voltage >>>>> might be too low to ensure proper ionization. If it's not adjustable, you >>>>> can boost it with a series DC supply such as a wall-wart transformer or a >>>>> small isolated DCDC converter. Anything from +12 to +24 should work fine, >>>>> and the current is pretty low (12mA). >>>>> >>>>> Once you get the HV supply resolved, you will be able to get more >>>>> current thru the tubes. BUT......you may want to stay with 8mA. From the >>>>> photo, the tubes glow nicely. Tube wearout is an exponential function of >>>>> current, so staying at the lower currents is better for longer lifetime. >>>>> At >>>>> some point, the current could be too low and you might see cathode >>>>> poisoning, but that's reversible. My gut feeling is that 8mA of pulsed >>>>> current should be fine. >>>>> >>>>> So, are you using rectified AC-mains as your DC supply ? No worries, >>>>> I've done that on several clocks and it can be done safely with proper >>>>> circuit design. >>>>> >>>>> On Thursday, October 26, 2023 at 7:28:18 AM UTC-7 Craig Garnett wrote: >>>>> >>>>>> The ongoing project of mine is coming on nicely but I need some >>>>>> reassurance with the way I'm driving the Z570s. >>>>>> >>>>>> There are two banks of 6 multiplexed tubes, from what I see from the >>>>>> datasheet these should run at 2ma static or up to 12ma as a 1 in 6 >>>>>> multiplex but that is using google to translate from the datasheet's >>>>>> German. >>>>>> >>>>>> The problem is that even with a 1K anode resistor I can't quite get >>>>>> 8mA from a 170V supply. >>>>>> The photo shows two tubes, the left is static at 2mA and the right is >>>>>> multiplexed at just under 8mA with a 1mS on time from a 170V supply and >>>>>> 1K >>>>>> anode resistor.. >>>>>> >>>>>> Is this ok or could I do it a better way? >>>>>> >>>>>> Thanks >>>>>> Craig >>>>>> >>>>> -- 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 view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/8872e9ce-ca83-46c4-80cc-4251c2de71ffn%40googlegroups.com.
