Hi Greg, The LEDs were 385nM, not 885nM. Clearly the LEDs were UV. I initially thought the 365nM would be more effective but they were not. The 365nM parts might have also been less desirable from a safety standpoint and were also quite a bit more expensive. The 405nM UV LEDs are less expensive and more plentiful but seem to have more visible light spill. I wish that I could edit the original post, but no such luck!Jeff -------- Original message --------From: gregebert <gregeb...@hotmail.com> Date: 2/19/24 10:56 PM (GMT-06:00) To: neonixie-l <neonixie-l@googlegroups.com> Subject: Re: [neonixie-l] Helping Nixie Tubes Fire in a Darkened Room 885-890nm ? That's infrared. If the LEDs are always-on, then I'm glad you're using IR instead of UV because it's much less harmful (perhaps harmless ?) to materials and humans/pets, etc.BTW, those are really interesting tubes. I dont think I've ever seen tubes with a solid/opaque anode.On Monday, February 19, 2024 at 5:19:12 PM UTC-8 Jeff Walton wrote:I posted this a couple months ago regarding the MG-17G display tubes that wouldn’t fire reliably in the dark. The final resolution for it was to mount some 885-890nM UV LED’s under the tubes. A completely updated display board with LEDs driven from a fixed supply and a transistor on an LDR so that they LEDs only turn on in a darkened room. This 885nM wavelength seemed to work better than the 865mM and was less visible than the 905nM LEDs. I wasn’t trying for a visible underlighting effect on the tubes, so they are being driven at about 2mA so that there is sufficient light without excessive glow. The clock is a Richard Scales design and this is the only one (so far) with the “keep alive” LEDs. The tubes do not have a keep alive cathode, so this method works. Otherwise, any single segment or decimal point would not fire reliably. Now the tubes light dependably. Thanks to Richard for the new board and a lot of back and forth to get this working right! The original PCB: The new PCB: The display in operation: The case in Place with LEDs on: The finished clock: Once we got past the issues with dark operation, the clock performs very well! Regards, Jeff Walton jwalt...@gmail.comjwalt...@msn.com (952) 943-2064 Home (612) 865-5560 Cell From: neoni...@googlegroups.com <neoni...@googlegroups.com> On Behalf Of Jeff WaltonSent: Wednesday, November 29, 2023 8:44 PMTo: neonixie-l <neoni...@googlegroups.com>Subject: [neonixie-l] Helping Nixie Tubes Fire in a Darkened Room I've recently come across a situation where I have some tubes in a clock that are being directly driven and are having trouble starting when the room is darkened but light right up when a room light is turned on. These particular tubes were probably intended for use in a calculator. They are seven segment neon MG-17G tubes. Once the tubes have any of the segments lit, there is really no issue with the performance. It's when the tubes go completely dark if a space is used while scrolling a message or lighting a dash on and off to emulate a colon. I'm wondering if others have found any particular tricks to help convince tubes to light up. There is no "baselighting" and the HV is ~172v. I'm considering increasing the HV by 10-15v but don't want to over drive the tubes. Short of putting a radioactive source in the vicinity, are there other things that anyone has had any luck with? Jeff-- 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 neonixie-l+...@googlegroups.com.to view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/d5713f02-ec1d-493d-b12f-644fb080ee71n%40googlegroups.com.
-- 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 neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/bb3b4ba6-8597-48c9-af56-c0a9e3de97c7n%40googlegroups.com. -- 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 neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/65d43e4a.6b0a0220.2598d.2887%40mx.google.com.
