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OBSOLETE CMOS NEEDED

Greetings, I've been using Google with less than desired results. I have two CNC machine controls built by Fanuc about 27 years ago. They use CMOS memory. I believe these are 1K devices. Anyway, the number on the package is MD8401N. This number is in the middle of the package. They might be made by Fuji. If anyone can help locate 10 or so of these I'd really appreciate it. Thanks, Eric R Snow

Reply to
Eric R Snow
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Hi, Mr. Snow. That number really sounds like a date code (1st week of

1984).

Are there any other numbers or letters on the IC?

Chris

Reply to
Chris

Thanks for the reply Chris. There are the numbers 7825 or 7827 in the upper right corner of the chip when the chip is horizontal. Then stamped in the middle is stamped MB8401N. In my first posting I wrote that it was mD8401n, but looking again all the chips are marked MB8401N. The chips marked 7825 in the upper right have the numbers 608 stamped in the lower right. The chips marked 7827 are marked H00 in the lower right. In the upper left corner of all the chips is a symbol that is comprised of a circle with the letter S in the center and a wavy line running vertically through the S. What I know for sure is that these are CMOS devices and that they are used for memory and they are interchangeable, position wise, with any of the other 27 chips on that portion of the circuit board. The only thing they all have in common is the brand symbol and the MB8401N marking. ERS

Reply to
Eric R Snow

MB8401 is listed in this cross reference table:

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Looks like it could be a memory chip.

When looking up chip numbers cut away the N or P at the end, they are not really a part of the part number.

--
 Roger J.
Reply to
Roger Johansson

At first I thought Signetics, but they have just a bold S. (see

formatting link
)

See:

for a list of chip makers.

IIRC MB was used by Mitsubishi for RAM / ROM.

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John Bokma

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