seeking info on obsolete IC's

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Richard Nicewonger

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Jun 26, 2023, 3:46:39 PM6/26/23
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Hello everyone,

In my obsession with Nixie calculators, I recently acquired a Dietzgen ESR-1 which is a rebranded Casio FX-1.
It required the usual replacement of the power supply HV caps and a pass transistor and cap in another regulator circuit.
After all that, it is still 95% DOA. This is an early calc using “stone age” JMOS logic where a “1” is @ -24V and “0” is GND.
These IC’s are now more than 50 years old and mostly unobtainable. In order to troubleshoot anything, I would love to get
any data sheets that could identify IC functions. I have seen some of the more common ones online, but there are a few
from NEC such as uPD129C, uPD173D, uPD312C, uPD358C, and from Toshiba HD3113P that seem to be elusive.
Could there be any members that have knowledge of these IC’s or the calculator itself? Any help would be appreciated.

Thank you,

Rich N.


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