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This forum is part of our mission to promote the preservation of vintage computers through education and outreach. (In real life we also run events and have a museum.) We encourage you to join us, participate, share your knowledge, and enjoy.

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Powertran Cortex

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    Hi Stuart,
    This is where i bought the additional chips from.
    No comments on the prices please !, i didn't pay quite that much for the TMS9911.

    TMX9909 http://www.electricstuff.co.uk/forsale.html (none left).
    TMS9902 http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=220821398049
    TMS9911 http://www.ebay.co.uk/itm/ws/eBayISA...m=150583219031
    74LS612 http://www.ebay.co.uk/itm/ws/eBayISA...m=330538234440

    No joy at all on the 72LS2001 but there seems doubt that they even existed.

    I looked at the keyboard switchs and there is no identification on them at all.
    I had a quick look through RS and Farnell to see if i could spot anything that looks the same but i couldn't see any.
    I will take some close up pictures of them later if it will help.

    Jim

    Comment


      5 bidders pushed the price up to 41.00, maybe someone could make a batch of ten boards to sell on ebay, updated to use 512KB static ram and other (comparatively) easy to obtain parts, and using a pic to convert the data from a standard PC keyboard to whatever data the cortex rom expects.

      @Ksarul, I have only seen the TMS9995 in an ebay ad for 140, is it available for significantly less from the sources you use?

      Comment


        Originally posted by mnbvcxz View Post
        5 bidders pushed the price up to 41.00, maybe someone could make a batch of ten boards to sell on ebay, updated to use 512KB static ram and other (comparatively) easy to obtain parts, and using a pic to convert the data from a standard PC keyboard to whatever data the cortex rom expects.
        Makes me feel a bit better about the price i paid for the first set bought off ebay (before i found out he had more than one set).
        Has anybody managed to find out how he got all the Cortex bits, i did ask but got no reply.

        Jim

        Comment


          Originally posted by mnbvcxz View Post
          5 bidders pushed the price up to 41.00, maybe someone could make a batch of ten boards to sell on ebay, updated to use 512KB static ram and other (comparatively) easy to obtain parts, and using a pic to convert the data from a standard PC keyboard to whatever data the cortex rom expects.
          This has been suggested with most rare computer forums i'm on.
          But, at what point would you stop upgrading it ?
          You could put a complete Cortex into a logic array chip nowadays (has been done with BBC's etc).

          There are projects to use a Pic to convert a PS/2 keyboard to a parallel interface using a PIC (or other micros) on the net, i've been meaning to build one for my Microtan 65.
          The parallel keyboard interface was quite common on early computers.

          Jim

          Comment


            @mnbvcxz, I got the last 8 TMS9995 chips I bought for $7 each about a year ago. The source shows up on eBay every once in a while with various TMS99XX parts that he gets from other industrial sources as overstock. He had some TMS9995s up a couple of months ago for $5 each and a single buyer nabbed them all (5 of them, IIRC). Patience is key here, as he comes up with stuff pretty regularly. He goes by RJJLROS, and I've never had a problem with his product.

            @Jim Hearne, I'll try and get a PDF of the video fix file up where you can grab it sometime this week.

            The Cortex seller was somewhat surprised at the level of interest in them, due to the relative obscurity of the Cortex in general. There aren't a lot of us out there with systems, but it is definitely good to see that it is still alive! I'm just glad they ended up in the hands of folks who would build them and increase the population of surviving Cortices, instead of off in a rubbish bin somewhere.
            Enter My Mind At Your Own Risk!

            Comment


              Hi All,
              I've updated my revamped parts list here:
              http://www.quantums.info/cortex/Cortex Parts list.xls
              I've now added the rest of the keyboard parts and added extra columns to show the differences between the original ETI articles parts and the later kits.
              There are a lot of changes, especially on the rev B motherboard.
              Still work in progress.

              Thanks,

              Jim

              Comment


                Originally posted by Jim Hearne View Post
                Has anybody managed to find out how he got all the Cortex bits, i did ask but got no reply.
                Pure conjecture but ... from the return address on the package, the company he works for does non-destructive testing, and has been around since 1985. I wonder if they were bought to be used with instrumentation, but got pushed to the back of a cupboard and have been there ever since?

                Stuart.

                Comment


                  I've put on my web site a PDF of the cortex schematics which i've separated from the copies of the Powertran build manual (anotated ETI articles) that were on the FTP site.
                  These seem to tie up with my rev B mainboard but not the power supply board.
                  I added R74 and R75 names to the cpu schematic but apart from that they are the same, just in a easier to reference format. (IMO)

                  http://www.quantums.info/cortex/Cort...cs-updated.pdf

                  Fitted the first components to my PCB's today, 80 odd ceramic decoupling capacitors.

                  I hopefully have a decent scan of the Issue of PCN that had the Cortex 2 review in it coming in the next day or 2.

                  Jim

                  Comment


                    I've dug out my collection of ETI's and started scanning them onto the PC.
                    About 20 mins per issue if you have a scanner with a sheet feeder and a Guillotine.
                    I've found my copy of the ETI Electronics digest that had reprints of the Cortex build in it.
                    It seems to have the updated Schematics and parts lists.
                    I've put just the Cortex pages here:
                    http://www.quantums.info/cortex/Cort...st version.pdf
                    If you want the whole magazine let me know.

                    I've almost 2 complete sets of ETI's from around 1982 to 1992, the full set i'm cutting in half and scanning.
                    Does anybody want the other set ?
                    Unfortunatly only one copy of the original Cortex issue.

                    Jim

                    Comment


                      I've now got a copy of some more Cortex 2 build documents, these include the new smaller power supply board layout and parts list.
                      Will scan and upload tonight.

                      Jim

                      Comment


                        Cortex 2 power supply and some general assembly instructions.
                        http://www.quantums.info/cortex/Cort...structions.pdf

                        Jim

                        Comment


                          Originally posted by Jim Hearne View Post
                          Cortex 2 power supply and some general assembly instructions.
                          http://www.quantums.info/cortex/Cort...structions.pdf
                          Excellent, thanks Jim.

                          I did enjoy a little typo I saw in the instructions: "A mistake at this pint can be very time consuming to rectify." A lesson to us all not to drink and solder I guess.

                          Stuart.

                          Comment


                            Cortex video fix.

                            Thanks to Ksarul pointing out which issue it was in.
                            I know have the Video fix article from the Feb 1986 issue of ETI

                            It's here:

                            http://www.quantums.info/cortex/Cort...I Feb 1986.pdf

                            Sorry about the light / dark bands in the backround, the scanner light has started objecting to scanning all my ETI's and is flickering.

                            Jim

                            Comment


                              E-Bus Floppy Disk (and other) Cards

                              Just pointing out the availability of E-bus floppy disk and other cards at bargain prices:

                              http://quarndon.co.uk/index.php?main...ex&cPath=54_55

                              I'm guessing that an external floppy disk controller will need changes to any floppy software as the controller hardware address will probably be different to the internal controller ...?

                              Stuart.

                              Comment


                                I've uploaded the 4 page Cortex 2 review from the December 22nd 1984 Issue of PCN to my web site.
                                http://www.quantums.info/cortex/Cort...ec 22 1984.pdf

                                Interesting colour internal picture.

                                Jim

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