Looking at the data sheet and the last graph: Maybe the problem is my resistor is too low and should be 12k or higher. I will try it. used 8.2k because that is what they suggested..
On Fri, Feb 12, 2021 at 9:06 AM Dekatron42 <martin.forsb...@gmail.com> wrote: > Which datasheet do you use? I only have information with the full wave > rectifier. > > What happens if you use a 470nF or 1uF capacitor with the half wave > rectifier? I made some quick LTSpice simulations which shows that a higher > capacitor might work as the voltage seems to fall low enough between each > period, but only real tests can show if that works properly. > > /Martin > > On Friday, 12 February 2021 at 14:13:47 UTC+1 bung...@gmail.com wrote: > >> Hi Martin, I changed the circuit back to halfwave using a single diode >> from the bridge rectifier and changing the capacitor. This was absolute >> minimum change without moving anything else. Back came the >> erratic flashing. So it's not the diode. It just does not like half wave. >> My circuits are direct copies from the data sheet. >> Peter >> >> On Thu, Feb 11, 2021 at 5:21 PM Dekatron42 <martin....@gmail.com> wrote: >> >>> Nice that it works! >>> >>> My understanding is that they need rectified AC, with just a little >>> smoothing so as not to make it a pure DC voltage, as they extinguish during >>> the portion of the voltage when it is to low to maintain the glow, and they >>> are re-ignited when the voltage rise again as long as a trigger electrode >>> has the correct voltage to initiate a glow, much like a thyratron. >>> >>> Maybe you can find the reason for it working now compared to earlier >>> failures if you check the voltage across the Anode-Cathode-Ignition >>> electrode with an oscilloscope? >>> >>> I've also had some problems with CMOS ic's when I have had poor, or no, >>> connection to VCC/GND on the power pins - the circuit worked quite well >>> until I touched some pins. >>> >>> /Martin >>> >>> On Thursday, 11 February 2021 at 21:50:49 UTC+1 bung...@gmail.com wrote: >>> >>>> I have solved the problem but I don't understand why. >>>> Having tried all the suggestions except this, I went to a full wave >>>> rectifier. It is not quite the same as the data sheet but does the same >>>> thing. >>>> It also has the capacitor connected per the data sheet, the same as my >>>> half wave circuit that did not work. >>>> This is rock solid with no indication of any other flickering. I am >>>> using the first (worst) tube. Touching the glass has no effect. >>>> Apparently the tube does not like half wave. Perhaps it was my 1N4007 >>>> diode? They can switch too fast and maybe it needed a snubber. >>>> I also tried DC from a variable regulated power supply (HP 6448B up to 600 >>>> volt@1.5 amp, and no, I did not go that far). That locked the display >>>> on one digit. The data sheet says it needs rectified line, not DC. >>>> I am running my tests from an HP supply for the 5v and an isolation >>>> transformer driven by a Variac for the AC so I have full control of all >>>> voltages. >>>> This is my final schematic. It is driven by a PIC with parallel >>>> connectors for each display. I used a PIC to generate the BCD because CMOS >>>> would not drive the three 74141 for the Nixies. The PIC counts up and down >>>> at varying speeds which would have been more difficult with CMOS. >>>> [image: 8453 Circuit.jpg] >>>> >>>> >>>> >>>> On Thu, Feb 11, 2021 at 10:33 AM Dekatron42 <martin....@gmail.com> >>>> wrote: >>>> >>>>> Touching the glass means that you get a capacitive coupling which will >>>>> upset them somewhat, there was a special socket made for this by Philips >>>>> which has a partial metal screen surrounding the tube. The socket is >>>>> nicknamed "der Kuss" , "The kiss", due to its form. I couldn't find a >>>>> photo >>>>> on the Internet now but I know it exists as I have some in my storage and >>>>> in an instrument that uses them. That instrument is called PW4261 Timer, >>>>> some photos of the externals can be found on the Internet. On this socket >>>>> all of the resistors are mounted flush to the pins to minimize the >>>>> distance, but the capacitors and power supply is mounted some 40cm from >>>>> the >>>>> tubes themselves, likewise there are long wires to the drivers. >>>>> >>>>> You can also have a look at the manual for the PW4231 which I scanned >>>>> that can be downloaded from here: >>>>> https://frank.pocnet.net/other/sos/Philips_PW4232.pdf if that can >>>>> help you with the voltages for the drivers. >>>>> >>>>> /Martin >>>>> >>>>> >>>>> >>>>> On Thursday, 11 February 2021 at 15:50:55 UTC+1 bung...@gmail.com >>>>> wrote: >>>>> >>>>>> I meant dekatron in my last reply to gregebert. >>>>>> I have 3 of these tubes, all apparently new (NOS). >>>>>> Per your suggestion I tried the other two. One is almost perfect but >>>>>> flashes the 2 a bit when 8 is selected. The third is perfect unless I >>>>>> hold >>>>>> the tube in my fingers by the glass where I get lots of random flashing. >>>>>> Remember that the really bad one works perfectly with the capacitor >>>>>> moved as I mentioned. I don't know if touching the glass affects it. >>>>>> More later, I will be away this morning. >>>>>> Peter. >>>>>> >>>>>> On Thu, Feb 11, 2021 at 2:10 AM Dekatron42 <martin....@gmail.com> >>>>>> wrote: >>>>>> >>>>>>> Have you tried the circuit in the J.B Dance book below? Here they >>>>>>> use a center tapped transformer and also a much lower value capacitor, >>>>>>> only >>>>>>> 33nF versus 250nF in your circuit - I've only evere seen 33nF used in >>>>>>> real >>>>>>> instruments using these indicators. >>>>>>> >>>>>>> Quite a few of the Z550M/ZM1050 are broken internally, I have a box >>>>>>> of them, and that seems to be due to the welding of the internal parts >>>>>>> coming loose when shaken or hit hard (the same problem exists with the >>>>>>> B9012/NL9012 tubes - I have a few broken ones of those too with internal >>>>>>> pieces that have come loose) - sometimes you can hear these loose >>>>>>> pieces if >>>>>>> you shake the tube very carefully close to your ear. What usually >>>>>>> happens >>>>>>> is that a rather large round center piece comes loose and in the worst >>>>>>> case >>>>>>> shortens some of the electrodes but usually only makes it hard or >>>>>>> impossible to get all digits to light up poperly and some of them >>>>>>> trigger >>>>>>> easier than others due to the distances between electrodes are >>>>>>> differing, >>>>>>> shaking the tube a little moves that effect around so other digits will >>>>>>> start to work and vice versa. >>>>>>> >>>>>>> /Martin >>>>>>> >>>>>>> [image: JBDance-Z550M.JPG] >>>>>>> >>>>>>> On Thursday, 11 February 2021 at 06:02:24 UTC+1 gregebert wrote: >>>>>>> >>>>>>>> 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 >>>>>>>> bung...@gmail.com 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 <greg...@hotmail.com> >>>>>>>>> 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 >>>>>>>>>> bung...@gmail.com 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 <chu...@all2easy.net> >>>>>>>>>>> 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" <bung...@gmail.com> >>>>>>>>>>>> Sent: 2/10/2021 8:15:21 PM >>>>>>>>>>>> To: "neonixie-l" <neoni...@googlegroups.com> >>>>>>>>>>>> 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 neonixie-l+...@googlegroups.com. >>>>>>>>>>>> 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 neonixie-l+...@googlegroups.com. >>>>>>>>>>>> >>>>>>>>>>> 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 neonixie-l+...@googlegroups.com. >>>>>>>>>> >>>>>>>>> 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. >>>>>>> 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/7085da7d-27dd-46f3-9bba-9e2d369dcc4fn%40googlegroups.com >>>>>>> <https://groups.google.com/d/msgid/neonixie-l/7085da7d-27dd-46f3-9bba-9e2d369dcc4fn%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 neonixie-l+...@googlegroups.com. >>>>> >>>> To view this discussion on the web, visit >>>>> https://groups.google.com/d/msgid/neonixie-l/ad3deb14-52ce-4b11-b048-dd6dea83bdban%40googlegroups.com >>>>> <https://groups.google.com/d/msgid/neonixie-l/ad3deb14-52ce-4b11-b048-dd6dea83bdban%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 neonixie-l+...@googlegroups.com. >>> >> To view this discussion on the web, visit >>> https://groups.google.com/d/msgid/neonixie-l/dcd99e19-3b9c-406c-8057-d69f1547ce03n%40googlegroups.com >>> <https://groups.google.com/d/msgid/neonixie-l/dcd99e19-3b9c-406c-8057-d69f1547ce03n%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 neonixie-l+unsubscr...@googlegroups.com. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/93f9a715-47dd-4f8b-8fd4-89e03e0bb06bn%40googlegroups.com > <https://groups.google.com/d/msgid/neonixie-l/93f9a715-47dd-4f8b-8fd4-89e03e0bb06bn%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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