8087 6mhz Math Coprocessors like for IBM 5162 $10 Free S&H

[luvit]

These are not mine. I picked one up for my 5162 for $10
http://www.ebay.com/itm/111053821663
EDIT: Correction on the title.. these are for 80287 Math Co-processors

 

[Stone]

I've got an Intel D80287-10 if anybody's interested.

 

[SpidersWeb]

Don't need a maths co-pro right now, but it's awesome you have a 5162 :thumbsup:

 

[offensive_Jerk]

Are the Co-processor speeds supposed to match the CPU speed, or how does that work?

 

[per]

Are the Co-processor speeds supposed to match the CPU speed, or how does that work?

As log as it match or is faster than the CPU speed it should be OK.

 

[Stone]

Most 80286-12 processors are run with 6, 8 or 10 MhZ FPUs.

 

[per]

Ah, I forgot! The 287 core clock can be, and often is, separate from the CPU clock. It has an on-chip clock divider that can optionally be used.

The regular AT runs the FPU core at 2/3 the speed of the CPU using the internal clock divider, while the XT286 runs it directly with a separate 4.77MHz clock.

 

[Krille]

Most 80286-12 processors are run with 6, 8 or 10 MhZ FPUs.

287 FPU:s can run asynchronously which means they run at 2/3 of the CPU frequency. So that excludes the 6 MHz FPU unless it would actually be capable of running overclocked at 8 MHz.

I'd recommend reading "EVERYTHING YOU ALWAYS WANTED TO KNOW ABOUT MATH COPROCESSORS" by Norbert Juffa. It's a bit of a read but well worth the effort if you're interested in these things.

EDIT: Per was faster than me.

 

[offensive_Jerk]

So would this work on a 8mhz AT then?

 

[per]

So would this work on a 8mhz AT then?

Yes. The core NPU speed in an 8MHz AT is 5.3MHz.

 

[cr1901]

Good find... my 286 has been lonely and wanting a companion 287 for some time :D. I once tried using an 8087 in it before I learned that the pinouts are completely incompatible. The power supply not running the hard drive was a good hint :D!