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8087 Upgrade Fail; Fake chip?

mcsew2k

Member
Joined
Apr 11, 2012
Messages
34
Location
California
My first ever 8087. I received it sealed in an anti-static envelope; seller insists it is new old stock. I don the proper anti-static strap and proceed to plug in the chip. I set the DIP to OFF (Block 1, Switch 2) and my system won't even POST. Does anyone know how I can check if this chip is a fake (without tearing it apart)?
 
Doesn't sound as if you've got a good chip there. I assume that you did the usual checks; making certain that there are no bent pins and that the DIP is oriented correctly in the socket (i.e. not plugged in backwards or offset by a row).
 
Yea, no bent pins and in the right way. I just pulled out my XT and the same thing, no POST. I used Buy-it-now on eBAY and didn't notice I was buying from Hong Kong until I was paying. Not worth sending back, but I want to see if I can figure out if it is an intentional fraud, or simply a bad chip.
 
The HK sellers are variable. Some are outright frauds, selling relabeled chips (I suspect that your 8087 isn't even one under the ceramic--it is a cerdip, not a plastic chip).

On the other hand, I've had some great experiences with HK sellers.

You have to be careful.
 
I now have a 8087 that lets the system boot. Is there a program I can download that will test and/or exercise the 8087 chip?
 
Is there a program I can download that will test and/or exercise the 8087 chip?
CheckIt Diagnostics will check/test the 8087 maths co-processor.
The particular check/test is done during the 'System Board' test within CheckIt.
CheckIt refers to the maths co-processor as the "NPU" (numeric processor unit).
 
I remember fitting an 8087, and needed it for rendering. You could try a raytracing test with POV Persistance Of Vision, although I don't know if this software is still around. It knocked the rendering time of a picture of fractal generated islands in the sea from 12 hours without the co-processor to about 20mins with it. I remember being bowled over by that!
 
although I don't know if this software is still around. It knocked the rendering time of a picture of fractal generated islands in the sea from 12 hours without the co-processor to about 20mins with it. I remember being bowled over by that!
POV-RAY is still around, though it's been a while since they provided 16 bit binaries.

http://www.povray.org/

3.1g was the last version to have official DOS builds.
ftp://ftp.povray.org/pub/povray/Old-Versions/Official-3.1g/MS-Dos/

3.5/later they dropped 16 bit OS support -- but it's matured into a real 3d suite when paired with modeling software like Moray, which is now free as the folks at Pov-Ray put together the means to acquire control of it.

Still fun to play with -- especially with 3.5/later supporting multiprocessing so that 20 minutes is down to a few seconds on a i7... though you can still crank the quality and scene complexity up to where some scenes take hours or even days on a modern system -- stuff that would have taken years at 8087 speeds.
 
CheckIt Diagnostics will check/test the 8087 maths co-processor.
The particular check/test is done during the 'System Board' test within CheckIt.
CheckIt refers to the maths co-processor as the "NPU" (numeric processor unit).

I had an issue getting CheckIt onto a floppy that would work in the PC. To make a long story short, I was able to put in on a native 720 KB floppy using a DTK controller and it ran and passed my 8087 chip. Thank you for the help.

I only have Lotus 123 on catridges for the PCjr, but I know I have Borland QuattroPro. I will do some benchmark testing in the near future.
 
they also made a huge difference with cad drawing manipulation/renderings!
 
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