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.
