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I'm making a Nixie Clock and I had to buy from ebay some old SN74141 (KM155ID1 equivalent). Is there some newer IC which does the same things as this one, or similar, that I could get from big suppliers like Mouser, LCSC or DigiKey?

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    \$\begingroup\$ Just have a look at what all the modern nixie tube equipment uses. \$\endgroup\$
    – PlasmaHH
    Jan 17, 2018 at 14:25
  • \$\begingroup\$ Every design I could find used the IC mentioned above, I will have a further look \$\endgroup\$
    – prenone
    Jan 17, 2018 at 14:27
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    \$\begingroup\$ @AchilleMerendino Plasma is making a joke. Nixies have not been designed into new equipment in perhaps 40 or 50 years. So there are no modern alternatives, and most of the designers who used them are retired or dead. \$\endgroup\$ Jan 17, 2018 at 14:32

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Use discrete transistors- MPSA42 is an old TO-92 part but easily available. Rated at 300V. Or MMBTA42 if you prefer SMT. For example, from this website:

enter image description here

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  • \$\begingroup\$ I'm not familiar with driving Nixie tubes, having never worked with them, but the circuit diagram given in the 74141's datasheet has a reverse-bias zener diode to ground for each pin, although I'm not quite sure I understand the purpose of it. Are these necessary? \$\endgroup\$
    – Jules
    Jan 17, 2018 at 14:42
  • \$\begingroup\$ @Jules they are not necessary if the transistors are rated for the full B+ (tube terminology) voltage (170V in the above example). The 74141 (and the even older 7441) were only rated for 60 or 70V so they depended on the gas discharge characteristics of the Nixie \$\endgroup\$ Jan 17, 2018 at 16:44
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The 74141's datasheet includes an equivalent circuit diagram for its output stage. You could always just replicate that output stage in discrete components and use a modern decoder IC (e.g. 74HC42) to provide the decoding logic.

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K155ID1 seem to be still manufactured in Russia, and there also seem to be some surplus of these components. If you make device for retro purposes (rather than functionality) you may look for partner in Russia sourcing and sending required components to you.

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  • \$\begingroup\$ Do they actually have 201x date codes? Are those packages the Russian DIP with 2.5mm pitch? \$\endgroup\$ Jan 17, 2018 at 16:20
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    \$\begingroup\$ See also here chipdip.ru/product/k155id1. Pic shows 1992. Does actual year matter? 14-pin packages (7 in a row) with 2.5 mm pitch fits well into 2.54 mm through-hole pads and sockets. \$\endgroup\$
    – Anonymous
    Jan 17, 2018 at 16:35
  • \$\begingroup\$ If they're 25-year-old parts they're NOS (New-old stock) not (necessarily) still manufactured. Thanks for the info! \$\endgroup\$ Jan 17, 2018 at 17:49
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    \$\begingroup\$ I had been sourcing various components for my projects some time ago, and they were of year 89, as well as of 2009-2015. The shop I linked to also says that component manufacture date is 2016-2017. But in general you will certainly know only asking the shop or when receive the components :) \$\endgroup\$
    – Anonymous
    Jan 17, 2018 at 17:59

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