Great summary!
When you do the ionization tests, could you do those in light and dark conditions? If not, at least document lighting condition under test, i.e. natural light, incandescent light, fluorescent light etc. I am curious if that has a significant effect. From: [email protected] [mailto:[email protected]] On Behalf Of gregebert Sent: Friday, June 07, 2019 1:31 PM To: neonixie-l <[email protected]> Subject: [neonixie-l] RZ568m learnings I recently bought my first 3 RZ568m (Dalibor's replacement for the expensive and rare z568m) and wanted to share what I've found out, and see if others have additional info to contribute. 1. Construction. The most significant things I noticed are * Pins are not mounted thru the glass. Instead, there is an actual PCB in the base of the tube with pins that connect to bondwires into the tube. The big advantage here is that inserting/removing the RZ568m tube will not put any stress onto the critical glass-metal seal at the base of the tube. I think the best way to insert/remove the tube is to grasp the base, NOT the glass. * The crimp-style seal should reduce gas leakage and increase the tube lifetime because it's a longer barrier thru glass compared to other tubes/nixies. * Fill nib at the top of the tube. None of my other nixies have this; common for VFD and traditional amplifier tubes. Just be careful not to bump it. * Big !! Even though the symbol-height of 50mm seems like a small increase above a 40mm IN-18, the width is also substantially wider and visually it's much bigger tube than you would expect just by a mental extrapolation. I have a clock with fourteen IN-18's and I thought that was a big-enough tube. * Consistency. I have 1 tube from a much earlier batch than the other 2, and the internal design is the same as far as I can tell and except for the serial numbers the tubes look identical. Even spot welds are the same number and location. * Mercury pellet / getter. I see 2 places where a small plate of material is located; I'm assuming it's getter material that absorbs hostile impurities from the tube.. * I strongly suggest you watch the video of how the tubes are built * In my own opinion, this is a high-quality and solidly built tube. I saw no hint of workmanship or quality issues. It literally looks like it came from the assembly line at Burroughs or Valvo, etc. * Each tube is shipped in a "collector's edition" style box with excellent foam padding, and then enclosed inside another shipping box. You probably could drop and kick it many times without breaking the glass. 2. Electrical. I plotted I-V curves for 2 tubes and see expected behavior. I will post my plots in a later update. * Current always increases when voltage is increased; this is important to ensure stable operation. * Once ionized, the voltage drop varies minimally over the specified operating current (5-6.5mA in datasheet, 5-7mA on website). Both tubes were within a few volts of eachother. Around 130V for normal operation. Thus, it's probably not necessary to use a circuit based current-limiter; a simple anode resistor should be fine as long as you plan for tolerance, tube-aging, tube-to-tube variations, and power-supply variation. * I did not measure the ionization voltage accurately, but it's below the datasheet spec of 170V. Stated another way, make sure your anode supply voltage is an absolute minimum of 170V under worst-case conditions. When I have more time, I will measure this for each numeral. I'll try to measure it and post the findings. What I expect is that the ionization voltage will not vary significantly across cathodes due to the anode mesh construction. * Numerals are fully illuminated at a small-fraction of the operating current. At very low currents (less than 1mA), numerals are only partially glowing. In my opinion this is important to ensure uniform "wear" on the cathodes. * The anode mesh fully surrounds all of the digits. I think this will prevent any sort of metal-whisker growth between cathodes, such as what I have documented on IN-1 tubes. * I did not notice a large variation in brightness when the current was varied from 5-7 mA (the recommended operating range). Based on this, I will operate my tubes at 6.0mA, using direct-drive. * You can buy a set of 3 PC boards for socketing this tube from oshpark.com for about 15USD total, including shipping. I made a small nixie tester using this and a thumbwheel switch. 3. Next steps * I'll measure the ionization voltages, then post along with the IV curves. * I will design my own set of PC boards for a RasPi-based clock in the future, but I dont have a timeframe due to so many other projects in the queue. It's more than a year from now. * Over the next few months I'll acquire the additional 4 tubes I need for a clock, and collect data on them. -- 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] <mailto:[email protected]> . To post to this group, send email to [email protected] <mailto:[email protected]> . To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/4e8e9183-a463-4137-a4a7-99ea812b5453%40googlegroups.com <https://groups.google.com/d/msgid/neonixie-l/4e8e9183-a463-4137-a4a7-99ea812b5453%40googlegroups.com?utm_medium=email&utm_source=footer> . 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/008101d51dff%24b5580c10%2420082430%24%40gmail.com. For more options, visit https://groups.google.com/d/optout.
