A nice OKI

[CPUShack]

OKI MSM3758AS

Really nice die on this one

Think its 1979 production, but Japanese date codes can be a bit tricky

[amstrad84]

uf, japan oki 9951 is not 1999 but 1979? Can you explain it or post here convert table? Thanks.
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[Vegeta]

3-digit "Japan Integrated Circuit" date code
Most integrated circuits (IC‘s) manufactured by Hitachi and some other Japanese companies use a three digit/letter/digit code to define the year, month and week of manufacturing.
A-M --> January-December
Example: 3B4 reads as 4th week within February of the year 1973
http://www.datamath.org/Datecodes.htm

4-digit "Japan Integrated Circuit" date code
NEC, OKI etc.
The second character of the code is the last digit of the year of manufacture, the third character of the code is the 1-9 month production of January-September, the X - October, Y - November and Z - December.
Example: 9951 reads as May of the year 1979
http://calculatorlaboratory.blog119.fc2.com/blog-entry-85.htm (link no longer available)

[CPUShack]

yup that sounds right

and some use years according to the emperor lol

[amstrad84]

Ok, thanks for informations about OKI etc. I am satisfied now.
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