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Powertran Cortex

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    Well that's going to make construction a lot easier
    If he had advertised an almost complete kit. he might have got a lot more money for it, I don't think I could get the TI chips now ( unless he has more kits!), which is why I did not bid on the PCB's.
    Although if anyone is DESPERATE, they should enter tms9995 into the ebay search function, and they will see a company offering this chip for about 140, which seems a bit excessive to me.
    Best of luck with your build.

    I did buy a pair of tms9900 cpu's, it might be interesting to benchmark the cortex and a machine built with a 9900 and 16 bit memory to see which is faster.

    Comment


      Indeed, thought it's missing the TMS9909 floppy disc controller and i will want to put floppy drives on it.

      I did have a quick look around the net before i bought the boards and it did seem that most of the chips are available with reasonably sensible prices from the US or China etc.
      I also work in electronics and might be able to pull in a favour from some of our suppliers to locate other parts.
      But now i've got the complete kit thats not quite such a problem.

      I see there was a piggy back board that solved the problem of the rare TMS9909 FDC chips, need to look into that more.
      The TMS9902 serial port chip seems to have been used in the TI99/4A and i should be able to get one of those quite cheap.

      Has anybody got the missing Cortex user group mags ?

      My intention is to creat a web page(s) covering the build if people are interested.

      Thanks all,

      Jim

      Comment


        Just bought 2 off TMS9902's on Ebay for a tenner.
        See other sellers offering the same part for 150 !!!

        Jim

        Comment


          Chips.

          Managed to get hold of a couple of TMX9909 FDC (pre production TMS9909) chips so that will save messing around with the floppy daughter board.
          Also found the TMS9911 and 74LS612

          Just got to wait for them to get here from various parts of the world.

          Anybody else noticed that theres a IC14a (Nand gate) on the circuits but not trace of it on the board or parts list.
          I guess this was one of the late changes.
          I'll buzz out the bare board and see whats actually there instead, maybe they found a spare gate from another package.

          Jim

          Comment


            There have been more bare boards listed on ebay
            http://www.ebay.co.uk/itm/250879547778

            Comment


              Originally posted by Jim Hearne View Post
              Managed to get hold of a couple of TMX9909 FDC (pre production TMS9909) chips so that will save messing around with the floppy daughter board.
              Also found the TMS9911 and 74LS612

              Just got to wait for them to get here from various parts of the world.

              Anybody else noticed that theres a IC14a (Nand gate) on the circuits but not trace of it on the board or parts list.
              I guess this was one of the late changes.
              I'll buzz out the bare board and see whats actually there instead, maybe they found a spare gate from another package.

              Jim
              Gotta say, Jim, you seem pretty resourceful! As I said before, good luck with the build and getting it all together.

              Comment


                Website now up...

                Hi Guys,

                After much encouragement in the early days, I went ahead and pushed for my goal to encapsulate everything on a dedicated website: powertrancortex.com. The site, as of tonight, is where I envisioned it to be.

                I had two goals. Firstly, I wanted it to be easily accessible, rather than having to trawl through all these posts to find a links to the FTP site etc. Secondly, I was encouraged to extend the the existing material by adding all the disks I had in my possession along with tools to make use of them on a real Cortex.

                It has taken more or less all my spare time in the last 8 months to do this but it's all now available. I went through close to 100 disks to consolidate them into clean 'release' disks so that they were uncluttered and usable. I developed utilities so that anyone who has a Cortex with a TMS9909 Disk Interface can make use of them (Jim Hearne, looks like you showed up at just the right time!). Alternatively, everything works with my Cortex Emulator (many changes since the one that's on the FTP site).

                Please check it all out and give relevant feedback so that I can make corrections as needed.

                Evidently, my wife has a very long list for me...

                Enjoy!

                Comment


                  Originally posted by tms9995 View Post
                  Gotta say, Jim, you seem pretty resourceful! As I said before, good luck with the build and getting it all together.
                  Thanks.

                  You know what they say, Google is your friend

                  Jim

                  Comment


                    PCB Scans.

                    Hi All,
                    I've now scanned all the Cortex PCB's at 600dpi
                    They are on my web site here http://www.quantums.info/cortex/cort...s%20600dpi.zip
                    They are about 18 meg !
                    Please feel free to upload them to other sites and the ftp for backup purposes.

                    They aren't totally perfect as the boards were too big for the scanner so i had to scan in 2 halves and then join them together.
                    But they are fine for following track layouts.

                    Jim

                    Comment


                      Originally posted by mnbvcxz View Post
                      I did buy a pair of tms9900 cpu's, it might be interesting to benchmark the cortex and a machine built with a 9900 and 16 bit memory to see which is faster.
                      The Cortex, with its TMS9995 processor, is significantly faster than the 9900 (~twice the 'power') because the 9995 does instruction prefetch.

                      Comment


                        Originally posted by Jim Hearne View Post
                        There have been more bare boards listed on ebay
                        http://www.ebay.co.uk/itm/250879547778
                        And a third set of boards has now been listed.
                        I got the second set - for a price cheaper than the first!

                        Jim, on the Cortex 2 parts you got, are there any markings on the key switches that indicate who they're manufactured by and what the part number is? I'd also be interested in who you've bought chips from so far - by private message if appropriate.

                        Comment


                          Originally posted by Jim Hearne View Post
                          Some pictures of what i've just bought from the same guy selling the PCB's on Ebay.
                          Apart from a few missing TTL and RAM chips it's a complete basic Cortex 2 kit.
                          Who'd have thought a unbuilt kit would turn up after almost 30 years !
                          [ATTACH=CONFIG]6512[/ATTACH][ATTACH=CONFIG]6513[/ATTACH][ATTACH=CONFIG]6514[/ATTACH]
                          Did you get any assembly instructions with the kit, Jim? The PSU PCBs he's sending out appear to be for the Cortex 2 and have been redesigned from the one in the ETI article, but the PCB doesn't have any component markings on it. It might be bigger to accomodate a heatsink for the two transistors that were previously bolted to the metal case?

                          Comment


                            Sorry Stuart,
                            I didn't spot there had been more replies to this thread till just now.

                            The 3rd set of boards are already more as i put a bid on them as a spare set

                            Most of the chips came from Ebay, the TMS9911 cost the most, probably a bit too much but as i'd got the rest i didn't want to wait around to see if one came up cheaper.
                            The TMX9909 i found through google on a web site from a guy in the UK with a list of chips for sale but they were the only 2 that the seller had i believe.
                            There was another web site (Mikes electric site i think) with some TMS9911's on but when i asked about them the seller couldn't find them, shame as they were a lot cheaper.
                            The TMS9902 came from China, they came as a pair but one was with the kit so i will probably have a spare one of these once everything is working.
                            The 74LS912 also came from Ebay, from the US i think.

                            I'll go back through all the emails and list the sources, probably Monday at work.
                            The kit is at work so i'll look at the switchs then as well.

                            The mainboard as far as i can tell is the same as the ETI board layout, i've not cross referenced the parts list yet, i've been slowly typing it into Excel and reformatting it, separating all the IC's and idetifying the various parts of the circuit so i can work out what extra TTL chips i need to find (mostly from the loft).
                            The current version of the parts list is here: www.quantums.info/cortex/Cortex Parts list.xls

                            I've not looked at the power supply at all, the kit i bought seemed to have had all the parts for the power supply pinched including the torroidal transformer so to start with i'm just going to use a small PC power supply.
                            The seller did mention he had found some assembly instructions but as i belivde they were just reprints of the ETI articles i said not to worry about them.
                            If the power supply boards are different maybe i can get him to scan them in.
                            I will check the other side of the power supply PCB i have, i know it was a single sided board but maybe it had silk screen on the other side i didn't notice.

                            I think that maybe the PCB revision is the small letter after the name marked on the PCB
                            I have:
                            Power supply: PSd
                            Keyboard: KBa
                            Mainboard: MBb

                            Jim

                            Comment


                              I bid on the third set of boards as well, as I want to build a machine from scratch to compare to the one I bought off eBay a couple of years ago (missing the floppy controller and E-BUS components). That way I can do some safe smoke testing. . .

                              On the HTF components, I have a dozen or so of the TMX9909s, a few hundred TMS9901s and TMS9902s, a couple of TMS9911s (no extras there), and a few dozen of the 74LS612s. I use a lot of TI components for other projects, so I tend to keep them on hand if I can get an OK price on them.

                              BTW, the component numbering on my board doesn't match the ETI numbering either--that change seems to have occurred relatively early in the production run.

                              I also have to put up a later ETI article I found on a video fix for the Cortex (from 1987).
                              Enter My Mind At Your Own Risk!

                              Comment


                                Hi Ksarul,
                                I would be very interested in the video fix so i can add it while assembling the boards.

                                Many thanks,

                                Jim

                                Comment

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