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Force-feeding an 8087 to a PC

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  • Brian Heise
    I ve been doing some reading of the Sams Computerfacts schematics for the IBM 5150 and the PCjr in order to see how to build a daughtercard for the jr to add a
    Message 1 of 8 , Mar 2, 2006
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      I've been doing some reading of the Sams Computerfacts schematics for the IBM 5150 and the PCjr in order to see how to build a daughtercard for the jr to add a 8087 math coprocessor.  Now...beofre shooting at me...there was one made back in the day for just this purpose.  Because it was nearly $200 or so, it didnt sell well.  anyone else out here have experience with this modification?  Seems like a pretty easy solder job on a blank breadboard, but my reading of schematics can be juvenile at times...
       
      Brian


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    • B. Degnan
      No, but good luck. Bill
      Message 2 of 8 , Mar 2, 2006
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        No, but good luck.
        Bill

        At 12:59 PM 3/2/2006 -0800, Brian Heise wrote:
        >I've been doing some reading of the Sams Computerfacts schematics for the
        >IBM 5150 and the PCjr in order to see how to build a daughtercard for the
        >jr to add a 8087 math coprocessor. Now...beofre shooting at me...there
        >was one made back in the day for just this purpose. Because it was nearly
        >$200 or so, it didnt sell well. anyone else out here have experience with
        >this modification? Seems like a pretty easy solder job on a blank
        >breadboard, but my reading of schematics can be juvenile at times...
        >
        >Brian
      • Chris M
        Brian, why in heaven s name are you soldering anything! If it s as easy as wiring it up to a Peanut in a similar fashion as you see in the PC s schematic,
        Message 3 of 8 , Mar 2, 2006
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          Brian, why in heaven's name are you soldering
          anything! If it's as easy as "wiring it up" to a
          Peanut in a similar fashion as you see in the PC's
          schematic, then yes you do need a daughtercard, but
          it's going to plug into the the 8088's space (which
          granted will require some desoldering), and the 8087
          will plug into a socket (the 8088 too). Perhaps some
          jumpers possibly. Don't know if support is required in
          the BIOS. The 8087 works by having the 8088 offload
          certain instructions to it, but this requires special
          programming...it's not automatic. People used to think
          that having a math coprocessor automatically speeds up
          their computer. Not so. The software has to take
          advantage of the chip (it has it's own instruction
          set), stuph like Autocad and the like.
          My guess is this is a more complicated project then
          it at first seems. Proceed slowly. And for Pete's
          sake, put down that steaming soldering iron! LOL LOL
          And is the Peanut a minimum or maximum mode design?
          Try the question on classiccmp.org. Interesting, but
          proceed cautiously.
          There's also www.micro-zone.com for Peanut
          afficianados.

          --- Brian Heise <nampcjr@...> wrote:

          > I've been doing some reading of the Sams
          > Computerfacts schematics for the IBM 5150 and the
          > PCjr in order to see how to build a daughtercard for
          > the jr to add a 8087 math coprocessor. Now...beofre
          > shooting at me...there was one made back in the day
          > for just this purpose. Because it was nearly $200
          > or so, it didnt sell well. anyone else out here
          > have experience with this modification? Seems like
          > a pretty easy solder job on a blank breadboard, but
          > my reading of schematics can be juvenile at times...
          >
          > Brian
          >
          >
          > ---------------------------------
          > Yahoo! Mail
          > Bring photos to life! New PhotoMail makes sharing a
          > breeze.


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        • Brian Heise
          I was speaking with one of the members of micro-zone (Thats my site BTW) about doing this addition. The programming is not going to be found in any jr
          Message 4 of 8 , Mar 2, 2006
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            I was speaking with one of the members of micro-zone (Thats my site BTW) about doing this addition.  The programming is not going to be found in any jr specific programs, but is found in some general PC programs.  I wish to make a decent daughtercard with soldered-on solckets etc....Im not slinging the iron around TOO much ;)....As was told to me, the Racore PCID cartridge "should" be able to help the jr look for those calls to the 87. And my jr is pretty much maxed out...booting HDD, 1.4mb floppy, 5.25 (standard), blah blah blah...all the good stuff...
             
            Brian
             


            Chris M <chrism3667@...> wrote:
            Brian, why in heaven's name are you soldering
            anything! If it's as easy as "wiring it up" to a
            Peanut in a similar fashion as you see in the PC's
            schematic, then yes you do need a daughtercard, but
            it's going to plug into the the 8088's space (which
            granted will require some desoldering), and the 8087
            will plug into a socket (the 8088 too). Perhaps some
            jumpers possibly. Don't know if support is required in
            the BIOS. The 8087 works by having the 8088 offload
            certain instructions to it, but this requires special
            programming...it's not automatic. People used to think
            that having a math coprocessor automatically speeds up
            their computer. Not so. The software has to take
            advantage of the chip (it has it's own instruction
            set), stuph like Autocad and the like.
            My guess is this is a more complicated project then
            it at first seems. Proceed slowly. And for Pete's
            sake, put down that steaming soldering iron! LOL LOL
            And is the Peanut a minimum or maximum mode design?
            Try the question on classiccmp.org. Interesting, but
            proceed cautiously.
            There's also www.micro-zone.com for Peanut
            afficianados.

            --- Brian Heise <nampcjr@...> wrote:

            > I've been doing some reading of the Sams
            > Computerfacts schematics for the IBM 5150 and the
            > PCjr in order to see how to build a daughtercard for
            > the jr to add a 8087 math coprocessor.  Now...beofre
            > shooting at me...there was one made back in the day
            > for just this purpose.  Because it was nearly $200
            > or so, it didnt sell well.  anyone else out here
            > have experience with this modification?  Seems like
            > a pretty easy solder job on a blank breadboard, but
            > my reading of schematics can be juvenile at times...
            >   
            >   Brian
            >
            >            
            > ---------------------------------
            > Yahoo! Mail
            > Bring photos to life! New PhotoMail  makes sharing a
            > breeze.


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          • Chris M
            please to make your acquaintance Brian. What is the PCID cart anyway? Not familiar with that one. Jim Scheef who s on this list is a fan of the jr also. While
            Message 5 of 8 , Mar 2, 2006
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              please to make your acquaintance Brian.
              What is the PCID cart anyway? Not familiar with that
              one. Jim Scheef who's on this list is a fan of the jr
              also.
              While on the topic, I remember seeing an add with an
              IBM 5151 mono monitor sitting atop the jr. Was there
              an actual 3rd party add that made this possible?

              --- Brian Heise <nampcjr@...> wrote:

              > I was speaking with one of the members of micro-zone
              > (Thats my site BTW) about doing this addition. The
              > programming is not going to be found in any jr
              > specific programs, but is found in some general PC
              > programs. I wish to make a decent daughtercard with
              > soldered-on solckets etc....Im not slinging the iron
              > around TOO much ;)....As was told to me, the Racore
              > PCID cartridge "should" be able to help the jr look
              > for those calls to the 87. And my jr is pretty much
              > maxed out...booting HDD, 1.4mb floppy, 5.25
              > (standard), blah blah blah...all the good stuff...
              >
              > Brian
              >
              >
              >
              > Chris M <chrism3667@...> wrote:
              > Brian, why in heaven's name are you soldering
              > anything! If it's as easy as "wiring it up" to a
              > Peanut in a similar fashion as you see in the PC's
              > schematic, then yes you do need a daughtercard, but
              > it's going to plug into the the 8088's space (which
              > granted will require some desoldering), and the 8087
              > will plug into a socket (the 8088 too). Perhaps some
              > jumpers possibly. Don't know if support is required
              > in
              > the BIOS. The 8087 works by having the 8088 offload
              > certain instructions to it, but this requires
              > special
              > programming...it's not automatic. People used to
              > think
              > that having a math coprocessor automatically speeds
              > up
              > their computer. Not so. The software has to take
              > advantage of the chip (it has it's own instruction
              > set), stuph like Autocad and the like.
              > My guess is this is a more complicated project then
              > it at first seems. Proceed slowly. And for Pete's
              > sake, put down that steaming soldering iron! LOL LOL
              > And is the Peanut a minimum or maximum mode design?
              > Try the question on classiccmp.org. Interesting, but
              > proceed cautiously.
              > There's also www.micro-zone.com for Peanut
              > afficianados.
              >
              > --- Brian Heise <nampcjr@...> wrote:
              >
              > > I've been doing some reading of the Sams
              > > Computerfacts schematics for the IBM 5150 and the
              > > PCjr in order to see how to build a daughtercard
              > for
              > > the jr to add a 8087 math coprocessor.
              > Now...beofre
              > > shooting at me...there was one made back in the
              > day
              > > for just this purpose. Because it was nearly $200
              > > or so, it didnt sell well. anyone else out here
              > > have experience with this modification? Seems
              > like
              > > a pretty easy solder job on a blank breadboard,
              > but
              > > my reading of schematics can be juvenile at
              > times...
              > >
              > > Brian
              > >
              > >
              > > ---------------------------------
              > > Yahoo! Mail
              > > Bring photos to life! New PhotoMail makes sharing
              > a
              > > breeze.
              >
              >
              > __________________________________________________
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              >
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              >
              >
              > ---------------------------------
              >
              >
              >
              >
              >
              > ---------------------------------
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              > Bring photos to life! New PhotoMail makes sharing a
              > breeze.


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            • Brian Heise
              The PCID cartridge does one thing, it changes the Identification byte that tells the software, what kind of computer it is dealing with. Nothing more. With
              Message 6 of 8 , Mar 2, 2006
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                The PCID cartridge does one thing, it changes the Identification byte that tells the software, what kind of computer it is dealing with.  Nothing more.  With this being the case, a program might have instructions for a 5150 running an 8087 on it, but would bypass those instructions if it knew a jr was running the software in order to alleviate issues with the running of the program.
                 
                There were 3rd party as well as IBM original adapters to run monitors other than the 4863.  If I remember correctly, the 4863 came out right before the 4860 was released.  Very few pre-dating release pictures of the jr have the 4863 monitor in them.  I could be rememebring wrong of course.
                 
                Brian

                Chris M <chrism3667@...> wrote:
                please to make your acquaintance Brian.
                What is the PCID cart anyway? Not familiar with that
                one. Jim Scheef who's on this list is a fan of the jr
                also.
                While on the topic, I remember seeing an add with an
                IBM 5151 mono monitor sitting atop the jr. Was there
                an actual 3rd party add that made this possible?

                --- Brian Heise <nampcjr@...> wrote:

                > I was speaking with one of the members of micro-zone
                > (Thats my site BTW) about doing this addition.  The
                > programming is not going to be found in any jr
                > specific programs, but is found in some general PC
                > programs.  I wish to make a decent daughtercard with
                > soldered-on solckets etc....Im not slinging the iron
                > around TOO much ;)....As was told to me, the Racore
                > PCID cartridge "should" be able to help the jr look
                > for those calls to the 87. And my jr is pretty much
                > maxed out...booting HDD, 1.4mb floppy, 5.25
                > (standard), blah blah blah...all the good stuff...
                >   
                >   Brian
                >   
                >  
                >
                > Chris M <chrism3667@...> wrote:
                >   Brian, why in heaven's name are you soldering
                > anything! If it's as easy as "wiring it up" to a
                > Peanut in a similar fashion as you see in the PC's
                > schematic, then yes you do need a daughtercard, but
                > it's going to plug into the the 8088's space (which
                > granted will require some desoldering), and the 8087
                > will plug into a socket (the 8088 too). Perhaps some
                > jumpers possibly. Don't know if support is required
                > in
                > the BIOS. The 8087 works by having the 8088 offload
                > certain instructions to it, but this requires
                > special
                > programming...it's not automatic. People used to
                > think
                > that having a math coprocessor automatically speeds
                > up
                > their computer. Not so. The software has to take
                > advantage of the chip (it has it's own instruction
                > set), stuph like Autocad and the like.
                > My guess is this is a more complicated project then
                > it at first seems. Proceed slowly. And for Pete's
                > sake, put down that steaming soldering iron! LOL LOL
                > And is the Peanut a minimum or maximum mode design?
                > Try the question on classiccmp.org. Interesting, but
                > proceed cautiously.
                > There's also www.micro-zone.com for Peanut
                > afficianados.
                >
                > --- Brian Heise <nampcjr@...> wrote:
                >
                > > I've been doing some reading of the Sams
                > > Computerfacts schematics for the IBM 5150 and the
                > > PCjr in order to see how to build a daughtercard
                > for
                > > the jr to add a 8087 math coprocessor.
                > Now...beofre
                > > shooting at me...there was one made back in the
                > day
                > > for just this purpose.  Because it was nearly $200
                > > or so, it didnt sell well.  anyone else out here
                > > have experience with this modification?  Seems
                > like
                > > a pretty easy solder job on a blank breadboard,
                > but
                > > my reading of schematics can be juvenile at
                > times...
                > >   
                > >   Brian
                > >
                > >            
                > > ---------------------------------
                > > Yahoo! Mail
                > > Bring photos to life! New PhotoMail  makes sharing
                > a
                > > breeze.
                >
                >
                > __________________________________________________
                > Do You Yahoo!?
                > Tired of spam?  Yahoo! Mail has the best spam
                > protection around
                > http://mail.yahoo.com
                >
                >
                >   SPONSORED LINKS
                >         Vintage computer   Computer security 
                > Computer training     Field trip
                >    
                > ---------------------------------
                >   YAHOO! GROUPS LINKS
                >
                >    
                >     Visit your group "midatlanticretro" on the web.
                >    
                >     To unsubscribe from this group, send an email
                > to:
                >  midatlanticretro-unsubscribe@yahoogroups.com
                >    
                >     Your use of Yahoo! Groups is subject to the
                > Yahoo! Terms of Service.
                >
                >    
                > ---------------------------------
                >  
                >
                >
                >
                >            
                > ---------------------------------
                > Yahoo! Mail
                > Bring photos to life! New PhotoMail  makes sharing a
                > breeze.


                __________________________________________________
                Do You Yahoo!?
                Tired of spam?  Yahoo! Mail has the best spam protection around
                http://mail.yahoo.com


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              • Chris M
                dude, what s a 4863? Is the 4860 the standard color unit for the jr? __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo!
                Message 7 of 8 , Mar 2, 2006
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                  dude, what's a 4863? Is the 4860 the standard color
                  unit for the jr?

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                • Brian Heise
                  The 4863 is the IBM PCjr Color Display Chris M wrote: dude, what s a 4863? Is the 4860 the standard color unit for the jr?
                  Message 8 of 8 , Mar 2, 2006
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                    The 4863 is the IBM PCjr Color Display

                    Chris M <chrism3667@...> wrote:
                    dude, what's a 4863? Is the 4860 the standard color
                    unit for the jr?

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