Ghosting is usually caused by changing the cathode value too soon after turning off the anode at the end of the display time for that digit. Try waiting a millisecond with all anodes off before writing the next cathode value.
On Fri, Jul 17, 2020, 7:40 AM Paul Andrews <[email protected]> wrote: > > I have had a Canon X61884803 calculator display board for some time and I > am in the process of trying to use this directly rather than pull the tubes > from it. I figured out the basic circuit for it and put together a lash-up > to drive it. Naturally it is multiplexed and LTSpice shows that 120Hz is a > likely frequency. > > I subsequently found an actual circuit diagram, for a calculator that uses > this, here: http://madrona.ca/e/eec/calcs/Monroe650.html and it was > interesting to see the voltages being used. I haven't tried to reproduce > those voltages, instead driving it with a fairly standard set of 0V GND, > 200V for VH-1, 100V for VH-2 (cathode pullup) and 12V 'logic level' input > to the cathode transistor base resistor, though I have tried 8V through 20V > for this. > > I have only wired up a few of the connections to show I am on the right > path with this, but now I am trying to figure out the ghosting. With that > in mind, does anyone have the specs for the TMC1764 shown in the circuit > diagram? Or, if anyone has access to a calculator that uses this display > board, I would be interested to know the voltages on the outputs of this > chip and perhaps even the timings? > > It could also be that I need to actually wire all the connections up and > see how it looks... > > Thanks. > > -- > 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/22e8eedc-f5f6-4f5e-bba4-e4dccc0115fao%40googlegroups.com > <https://groups.google.com/d/msgid/neonixie-l/22e8eedc-f5f6-4f5e-bba4-e4dccc0115fao%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/CAPbqtver8r7AzaK4iHf6zmxH-d3VTcppuBL9-jaP_0nyZ6Em5g%40mail.gmail.com.
