I suspect the differential voltage between lit vs non-lit numerals is too low. The CMOS device is basically driving grids to determine which cathode will be illuminated. I've seen similar behavior with an A-101 dekatron. What voltage are you using for VDD ? Is it 8V as indicated on the schematic, or a more-conventional 5V ?
On Wednesday, February 10, 2021 at 7:22:25 PM UTC-8 [email protected] wrote: > I think you are wrong. The literature explains this tube is designed to be > driven by 5v logic and it does work. The steering electrodes are close to > the Anode voltage which is grounded and only 5v pulses (square waves) are > needed. Note all the cathodes are connected together internally. > I got to thinking about the C1 position. The data sheet shows it per my > schematic and I can't believe they made that mistake several times > including the hand drawn notes of the designer. I think maybe I needed to > have C1 directly on the socket pins and will try that tomorrow. > Thanks for your interest though but you are thinking Nixie Tubes, this is > a special tube with steering electrodes.. > > > On Wed, Feb 10, 2021 at 9:42 PM chuckrr <[email protected]> wrote: > >> That schematic is so wrong in so many ways. You need high voltage >> transistors operating the tube cathodes. >> >> You need high resistance drving the transistor bases. You need a buffer >> such as 4049 or 4050 driving the >> >> resistor, which in turn drives the transistor base. Only then would I >> dare to use the 4028....to operate the buffer, which in turn operates the >> >> transistor base via appropriate high resistance. That is the only sure >> fire way I know of to attain noise-free performance from CMOS logic >> >> driving cold cathode tubes. That schematic there is a noisy deal. >> >> >> >> >> >> ---- Original Message ---- >> From: "peter bunge" <[email protected]> >> Sent: 2/10/2021 8:15:21 PM >> To: "neonixie-l" <[email protected]> >> Subject: [neonixie-l] 8453/Z550M erratic >> >> Using the schematic from the data sheet >> [image: 8453 Circuit.jpg] >> This works with the count moving around but other numbers flash >> erratically, especially close to the number that is supposed to be lit. >> *When I moved the bottom of C1 to the other side of R1 it works >> perfectly. It is rock steady and does not care about line voltage or the >> 5v supply (shown above as 8v but used at 5v)* >> If this is an error it is continued through all the documentation and is >> consistent. Changing the value of C1 up and down by 10 had little effect >> but a smaller C1 helps a bit. My Rst are all directly on the socket pins >> and the wires are all about 5 inches long. >> I have varied the line voltage with little effect. >> Any suggestions??? >> >> -- >> 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/b996ef0b-edbb-4c77-8ec1-57255dd58a82n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/neonixie-l/b996ef0b-edbb-4c77-8ec1-57255dd58a82n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> >> -- >> 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/202102101842701.SM05295%40ADT-IM1 >> >> <https://groups.google.com/d/msgid/neonixie-l/202102101842701.SM05295%40ADT-IM1?utm_medium=email&utm_source=footer> >> . >> > -- 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/9543e23e-ebb0-46e7-8624-ddcf4a843667n%40googlegroups.com.
