Just a thought, maybe the diodes originally used had a much different reverse leakage which, in half wave rectified setup, caused the polarity in the tube to flip slightly - at low leakage current levels - and thus extinguish it more cleanly between ripples. Modern(!) silicon (verses germanium) may be too sharp for it? I think your full wave design is probably best anyhow, the half wave was likely a cost compremise! - Alex
On Friday, 12 February 2021 at 20:08:35 UTC bung...@gmail.com wrote: > I tried Rk at 12k and 22k and it is still erratic. > Next I went back to full wave and connected it to my display chassis that > runs from a PIC that counts at various speeds. I see the circuit only > counts slowly but at 10/sec it fails. No flickering, it just does not count. > I changed the capacitor to the other side of Rk and it works perfectly. > I can't believe it is a typo carried through three documents but companies > have been known to intentionally place errors to cause grief to anyone > trying to steal their designs. > This circuit works. > [image: 8453 Circuit.jpg] > > On Friday, February 12, 2021 at 12:47:29 PM UTC-5 Dekatron42 wrote: > >> Thanks, I've never looked at that particular datasheet previously, only >> the Philips ones even though I have a few Amperex stamped Z550M's. >> >> In this document: https://www.dos4ever.com/Z550M/Z550M2.pdf (a somewhat >> clearer PDF can be downloaded here: >> http://www.tube-tester.com/sites/nixie/dat_arch/Z550M_2.pdf) there is a >> paragraph on "Supply voltage" on page 120 where they mention a minimum >> repetition frequency of 80 pulses per second as a minmum for proper >> operation - perhaps that is the reason why it doesn't work as well on just >> half wave rectification. Maybe Amperex had some specially made to be able >> to drive them at 117 VAC @ 60Hz? >> >> /Martin >> >> On Friday, 12 February 2021 at 17:56:07 UTC+1 bung...@gmail.com wrote: >> >>> Martin; See attached for data sheet. I have tried different capacitors. >>> They make no difference for either full wave or half wave - full wave >>> always works with no indication of problems and half wave flickers all over >>> the place and never works (unless I move the capacitor connection). >>> >>> Bill van Dijk: I am in Canada, 60 Hz. Control grid?? See data sheet >>> attached. >>> >>> I was hoping someone else would have tried these circuits. I have used a >>> 'scope to check the various signals and they look fine. >>> >>> On Fri, Feb 12, 2021 at 9:06 AM Dekatron42 <martin....@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+...@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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