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Any interest in a PCjr CPU upgrade board?

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    #16
    I’d definitely be interested.

    - Alex

    Comment


      #17
      Originally posted by mbbrutman View Post
      Hi Ted,

      ... A super fast PCjr is kind of silly. ;-0
      Yep. Kind of silly. But silly mods make these old machines a blast to play with. I have three 5155s. Only one is stock. Other two have a bunch of "Really Silly MODS". I play with all three but the modded ones tend to get used more.

      Greg

      Comment


        #18
        Originally posted by ibmapc View Post
        Yep. Kind of silly. But silly mods make these old machines a blast to play with. I have three 5155s. Only one is stock. Other two have a bunch of "Really Silly MODS". I play with all three but the modded ones tend to get used more.

        Greg
        Care to share what your silly 5155 mods are and do Greg?

        Comment


          #19
          Originally posted by brain View Post
          You can buy those headers from Digikey/Mouser. I sell a machine pin version in my store:

          http://store.go4retro.com/ic-header/

          The pins on these are very narrow, and do not affect cheap wiper sockets. But, you can also buy the flat pin versions (they cost more):

          https://www.digikey.com/products/en/...=1&pageSize=25

          Aries sells them (looks like they only have forked pin option at Digikey, but they sell the simple post version as well. I used to buy them, and they work fine.
          On your site you specify the pin diameter is 0.060" - is that a mistake? That's larger than a standard PTH for a .100" pin header

          Comment


            #20
            Originally posted by VERAULT View Post
            Care to share what your silly 5155 mods are and do Greg?
            I'd be glad to. But, I'll start a new thread later today for it so as not to hi-jack this one.

            Comment


              #21
              https://microcorelabs.wordpress.com/...jr-on-the-way/

              It's on the way...

              Comment


                #22
                Aries makes a series of coined (flat stamped) pin headers in a variety of sizes. I also recently purchased a full reel (50,000 pins) of Batten & Allen pins (the same ones Alan linked, I'd originally gotten my smaller quantity for Matt D'Asaro ). Henry Courbis (ReActive Micro also recently bought a reel of Batten & Allen pins, though his are bare copper with no plated finish, last time I talked to him he was potentially interested in supporting other hobbyist open source projects with his stock of them, too.
                Check out The Glitch Works | My Retro Projects | Vintage Computer Services | Glitch Works Tindie Store -- Vintage Computer Kits and More

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                  #23
                  if you can make this work in others 8088 computers i could go for it any day of the week .
                  I suppose if it works on the JR it should work on a tandy ?.

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                    #24
                    A 8086 version of this would be AMAZING.

                    Comment


                      #25
                      > A 8086 version of this would be AMAZING.

                      The MCL86 core's Execution Unit (EU) actually is an 8086; just like the real Intel device. It is only the Bus Interface Unit (BIU) that makes it an 8088 or 8086. So it can easily be ported to an 8086 design.

                      What system did you have in mind?

                      Comment


                        #26
                        The PS/2 model 25. Other model 25 and 30 owners would probably really like this also. It would have to be like your dirst design probably to clear everything though: http://ibmmuseum.com/Planars/Model25...aYWeytO9TT2Gnk

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                          #27
                          Originally posted by soviet9922 View Post
                          if you can make this work in others 8088 computers i could go for it any day of the week .
                          I suppose if it works on the JR it should work on a tandy ?.
                          A Tandy 1000 runs its 8088 in max mode, not min mode, and the memory map is different, so presumably it would need some modifications.
                          My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs Also: Blogspot

                          Comment


                            #28
                            Originally posted by Trixter View Post
                            As someone who thinks this project is cool, I cheer you on from the sidelines. However, I'm not sure I could pony up $200+ for a board.

                            Is there anything that limits it to the PCjr? Asking because it might be interesting to see if your replacement could be made generic enough to replace any 4.77 MHz 8088 in any system.

                            My sentiments exactly. And I don't even have a PCjr (yet).
                            I feel cpu upgrades for old systems are AWESOME, but as my collection has grown to fill a 4-car garage, the ROI just isn't there for me. If I want to run something that benefits from a 286, I pull out my model 60 or 5170. And I own a good number of accelerator cards for these machines. (my model 80 is a 486/25 right now).

                            I just feel 2020 hardware in a 1984(ish) machine just defeats the spirit of the machine. If I wanted to play pcjr games at 100fps, i'd just fire up an emulator. Its the reason I have the huge PEB box for my ti-99/4a and not that little credit card that does everything.

                            That said, I want you to continue. I want to see this a finished project. I will be sad if this doesn't pan out.
                            It is a mistake to think you can solve any major problems just with potatoes.

                            Comment


                              #29
                              PS/2 model 25 owners like me have to wait long periods of time for very rare CPU upgrades. I got a 33Mhz 386SX upgrade for my model 25/286 after two years of waiting for one to pop up - and it wasn't cheap. I think due to other bottlenecks in the system it will still feel "vintage", but for people with certain computers they really like this kind of thing is really cool.

                              Comment


                                #30
                                How about an Olivetti M24 or an AT&T 6300?

                                Originally posted by Simplethings View Post
                                Originally posted by MicroCoreLabs View Post
                                > A 8086 version of this would be AMAZING.

                                The MCL86 core's Execution Unit (EU) actually is an 8086; just like the real Intel device. It is only the Bus Interface Unit (BIU) that makes it an 8088 or 8086. So it can easily be ported to an 8086 design.

                                What system did you have in mind?
                                The PS/2 model 25. Other model 25 and 30 owners would probably really like this also. It would have to be like your dirst design probably to clear everything though: http://ibmmuseum.com/Planars/Model25...aYWeytO9TT2Gnk
                                I would be very interested in trying such an upgrade on an Olivetti M24. Really curious to see what performance that old beast would be capable of with any CPU bottlenecks removed.

                                Does this FPGA core also support the additional V20/V30 instructions, by the way?

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