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SiriusHardware · 3rd Aug 2021, 5:54 pm

Ah, right. Changing the value of that pullup resistance may have unintended consequences, as observed earlier. The value seems important, or to be more precise, based on earlier observation, it ideally needs to be no more than 4K7.

If you remember, the capacitors appear to fix some sort of timing relationship between the rate of change of the states of A8-A11 and NWDS but raising the value of the pullup resistor (thereby slowing the rate of change of NWDS) actually cancels out some of the effect of the capacitors.

3rd Aug 2021, 5:54 pm	#156
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,560	Re: Ortonview PCB Ah, right. Changing the value of that pullup resistance may have unintended consequences, as observed earlier. The value seems important, or to be more precise, based on earlier observation, it ideally needs to be no more than 4K7. If you remember, the capacitors appear to fix some sort of timing relationship between the rate of change of the states of A8-A11 and NWDS but raising the value of the pullup resistor (thereby slowing the rate of change of NWDS) actually cancels out some of the effect of the capacitors.