So is it an issue towards tube life or nothing to worry about? Craig
On Wednesday, 1 November 2023 at 05:51:23 UTC gregebert wrote: > I'm speculating that in order to get the higher current for multiplexed > operation, the increased voltage was enough to coax a bondwire into > glowing. I have a few 5031 nixies that are so worn-out that only the > bondwires glow. > > On Monday, October 30, 2023 at 1:43:57 PM UTC-7 Greg P wrote: > >> Interesting. >> >> On Monday, October 30, 2023 at 2:27:50 PM UTC-4 Craig Garnett wrote: >> >>> The directly driven tube is just 2mA and that doesn't light the pins. >>> If I swap the tubes then it stays with the multiplexed tube. >>> >>> On Monday, 30 October 2023 at 14:58:31 UTC Greg P wrote: >>> >>>> 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. 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