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                INTEL MATH COPROCESSOR HARDWARE TROUBLESHOOTING             
                                                                            
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   386 XENIX/UNIX AND THE 387DX
   

       When 386(TM) versions of Xenix or Unix run on a computer containing an
       Intel 387DX math coprocessor, the computer can lockup intermittently.
       Read FaxBack document #3054 for more detailed information on this
       problem.


   387DX & WEITEK SOCKETS
   

       Many computers contain with a square socket for a Weitek math
       coprocessor.  This  socket has three rows of holes on all four sides.
       In many computers, such as the Compaq 386, the inner two rows of pins
       are compatible with the Intel 387DX.  This  gives you the option of
       using an 387DX or the Weitek math coprocessor.

       However, if you want to install an 387DX in the Weitek socket, you must
       use EXTREME CAUTION to orient the chip correctly; otherwise you could
       damage the computer and the 387DX.  Read your computer's User Guide to
       determine the correct procedure for installing the 387DX in your
       computer.  The Installation Guide for the 387DX contains general
       information which may be useful also.  If you have trouble figuring out
       how to correctly install the chip, have your dealer perform the
       installation for you.  Intel can't replace a part which has been
       destroyed by incorrect installation.

       Some computers use the Weitek socket but DO NOT support the 387DX, such
       as the TANDY 4000.  Contact your computer manufacturer or dealer for
       more specific information.


   387DX/MATH UNIT AND IBM ADVANCED DIAGNOSTICS
   

       The 387DX and Inboard 80287 Math Module will fail the IBM  Advanced
       Diagnostics.  This happens because the diagnostics  reinitialize the
       387DX or Math Module after the Inboard 386 has already initialized it.
       Use the CHKCOP program on the Inboard 386 diskette to test an 387DX or
       Inboard math module.








   

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   BURNED PIN ON 387DX
   

       The most common cause for burned pins on the 387DX is incorrect
       installation.  In many computers, the 387DX is oriented differently
       from the other large chips.  Carefully follow the manufacturer's
       installation instructions to avoid damaging the 387DX.  The Intel
       warranty doesn't cover chips which were installed incorrectly.


   COMPAQ COMPUTER PROBLEMS
   

       If, after adding an Intel product (such as INBOARD, ABOVE BOARD or Math
       Coprocessor), your COMPAQ 286 computer begins to reboot itself
       automatically, it is usually a symptom of one of two problems:

         The connection between the power supply and the system board could
          be defective.  The computer will continue to operate until either an
          additional burden is placed on the power supply, or enough oxide
          builds up to cause the failure.  The cure for this is to vigorously
          reseat the connection.  Be careful to not apply excessive force and
          break the connector or system board.

          The power supply could be taxed beyond it's capabilities.  The only
           solution for this problem is to replace the power supply with a
           bigger one.


   REMOVING 80287 FROM IBM PC AT
   


   After removing a math coprocessor from an IBM PC AT computer, you must
   rerun your computer's  SETUP program.  If you still receive an error
   message because the computer can't find the chip, you may have to
   temporarily unplug the battery from the system board.  All SETUP
   information will be lost, so be sure to write down the hard drive type,
   floppy drive type, memory and video configurations before unplugging the
   battery.  This information is critical in correctly reconfiguring your
   computer.










   

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                INTEL MATH COPROCESSOR HARDWARE TROUBLESHOOTING             
                                                                            
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   REPLACEMENT 8088
   

       If you have an 8087 and a 4.77-MHz 8088 dated '78, you can get a free
       replacement 8088.  Contact Intel Customer Support for the replacement.

       NOTE:  Only 4.77-MHz 8088 chips need to upgraded.  The 8088-2 and 8088-
              1 do not require replacement.


   IBM PS/2 MODEL 80, 387DX & NOISE FROM SPEAKER
   

       Some of the 8580 Models 111 and 311 with math coprocessors installed
       may experience trouble with the speaker.  You may hear crackling or
       beeping noises while the computer is running.  the 387DX doesn't cause
       this problem.  The  following computers may have the problem:

         8580 Model 111, with serial numbers below 6019000
         8850 Model 311, with serial numbers below 6502022































   

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