OBSOLETE CMOS NEEDED

[Eric R Snow]

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

 

[Eric R Snow]

On 1 Jul 2005 12:33:54 -0700, "Chris" <cfoley1064@yahoo.com> wrote:

Eric R Snow wrote:
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

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
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

 

[John Bokma]

Eric R Snow <etpm@whidbey.com> wrote:

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.

At first I thought Signetics, but they have just a bold S.
(see http://www.zianet.com/kromeke/pastcomp/misc/2650_lg.jpg )

See:
<http://www.chipdocs.com/manufacturers/list.html?okwd=M37516&partid=273986
&ReR=GG>

for a list of chip makers.

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.

IIRC MB was used by Mitsubishi for RAM / ROM.

--
John MexIT: http://johnbokma.com/mexit/
personal page: http://johnbokma.com/
Experienced programmer available: http://castleamber.com/
Happy Customers: http://castleamber.com/testimonials.html

 

[Roger Johansson]

Eric R Snow wrote:

common is the brand symbol and the MB8401N marking.

MB8401 is listed in this cross reference table:
http://matthieu.benoit.free.fr/cross/mb.htm

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.

 

[Chris]

Eric R Snow wrote:

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

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