If you have an isolation transformer, can you put a scope on the cathode line to verify the ripple is not excessive ? Rk and Ck create an RC filter around 77Hz, and the line is 50-60Hz, so there could be some ripple.
On Wednesday, February 10, 2021 at 8:26:51 PM UTC-8 [email protected] wrote: > I tried varying it with absolutely no effect. It runs perfectly at 5v with > the capacitor moved to the other side of the resistor. However I was > clocking slowly. It may not run at spec speed. I seem to remember reading > of using 5 to 8 volts for the logic. > The data sheet shows the following which I'm inclined to believe. I will > try Ck directly on the pins tomorrow. Someone must have tried this circuit. > [image: 8453 Cct.JPG] > > On Wed, Feb 10, 2021 at 11:12 PM gregebert <[email protected]> wrote: > >> 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 >> >> <https://groups.google.com/d/msgid/neonixie-l/9543e23e-ebb0-46e7-8624-ddcf4a843667n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. 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