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4C87DLC-40 --> type of NPU? + installation in socket

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First post, by MaTi

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Hi all,

Two quick questions. I bought an IIT 4C87DLC-40 coprocessor for my new 386 build.
On my board I need to jumper it for either an '80387' or '3167' type of NPU. Which of the both should I set and what is the difference?

Also, the socket ofn my board looks like this:
236747d8-e701-4af1-b04c-ef001363545e.jpg

Do I put pin1 of the chip in position 'a1' on the board, or do I center the chip in the socket, meaning pin1 would end up in 'b2'?
Also, how do I see what pin 1 on the co-proc is? I see a small bulge on one of the four corners.. I asume thats where pin1 is.. Is that correct?

I googled for the chip to show what I mean (not my own chip):
s-l400.jpg

Thanks!

Still relatively new, but spending too much time on retro already.. 😀

Reply 2 of 4, by MaTi

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Great, thanks! Now, to be sure.. The socket is bigger than the chip. I believe I should center it in the socket, right? Leaving the rows of holes on the egdes unpopulated, correct? thanks 😀

..and it is a 3167 or 80387, if you happen to know please?
(and as I like to learn: whats the difference between both?)

thanks 😁

Still relatively new, but spending too much time on retro already.. 😀

Reply 3 of 4, by Anonymous Coward

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80387.
3167 is a different IC made by Weitek that is physically larger than an 80387.
Your chip has a confusing name.. The older ones were called '3C87' (C for CMOS). IIT renamed their later ones to '4C87' to match the Cyrix 486DLC CPU (a 386 type CPU). As far as we know a 3C87 and 4C87DLc are 100% the same.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

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