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Powertran Cortex

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    Fake TMS9909 and real TMX9909.jpg
    UTsource was where one of mine came from, sorry.
    I've just sent them a snotty email but i bought it back in May so probably not much else will happen.
    Looking at them now, what i assume are the date codes are totally wrong, one is 9808 and the other 0440, way too late for TMS9909 production.
    The TMX9909 has a date code of 8314

    If you want to do a test of yours, hook up 0V to pin 1 and 5V to pin 23, the good chips draw about 110ma (Spec says 150ma nominal), the fakes are 5ma and 31ma.


    Jim
    Last edited by Jim Hearne; October 29, 2012, 08:44 AM.

    Comment


      Actually I just checked what I bought. I got one TMS9909NL which looks kinda dodgy like the ones above and a TMS9911NL which does look pretty good, with a date code of 8745, but who knows. I'm now pretty reluctant to try them in case they blow something up! I appreciate the current measurements, though.

      Dave.

      Comment


        I'll add a bu**er" as well. I bought two of the 9909s. "If it's too good to be true ..."

        Stuart.

        Comment


          I have a small number of TMX9909s as well as the TMS9909s I was suspicious of (I sent the one Jim has as a test object). Thanks for the confirmation of my suspicions, Jim! I got the TMX chips from a reliable US source, so they "should" be good. I think I bought 7-8 of them. Right now the one chip I don't have a good stock of are the 9911s. About the only regular source of them I see is Little Diode on EBAY, and they're a bit expensive there. . .
          Enter My Mind At Your Own Risk!

          Comment


            My TMX9909 came from the US as well, just from a list of spare chips somebody had on their web site, i think i had the last 2 though.
            The TMS9911 i bought from Little Diode , they did give me a better price than they had on Ebay but it was still expensive (34usd).

            I've fitted all the floppy chips and connected up a pair of old BBC floppy drives.
            Got to the stage where it appeared to be trying to read the floppy but something in the drive decided to put gunk all over the disk surface so need to look at that.
            Also not made a Cortex boot disc yet, got to get the PC to do that.

            Jim
            Last edited by Jim Hearne; October 30, 2012, 04:02 AM.

            Comment


              [rant mode]

              Did you guys get the notification from ebay that they're no longer supporting wildcard searches? I've got a search for "tms99*" to find all the TMS99xx series chips that come up. But ebay in their wisdom reckon that isn't giving me the search results I want. Apparently now I have to provide a search term for each individual chip as searching for just "tms99" only returns 3 results versus the 118 results that the wildcard search gave ...

              [/rant mode]

              Comment


                I didn't even realise you could use wildcards like that.
                But, i do know they've "improved" the search a few times in the last year or so.
                Searchs i've had setup for years that used to return only exactly what i was looking for, nowadays return auctions with similarly spelt and parts of the actual search terms i've requested.
                E.g my search for Microtan (as in Microtan 65) now returns hits for Micron memory all the time.

                Jim

                Comment


                  Floppy drives working.

                  Finally got the floppy drives working.
                  I found Daves great utilitys on www.powertrancortex.com which lets you download programs from a PC to the Cortex through the RS232 interface and then lets you create disk images on the Cortex itself.
                  There are so many combinations of sides, tracks, density etc that initially i couldn't get it working.
                  But eventually i got the combination right and was able to create the SS SD 80 track boot disc.
                  And then finally BOOT worked.
                  I then created a DS DD 80 track disk but while it appeared to download and write ok using Daves utility i get disk controller errors trying to access it.

                  But then Dave does say DD is tricky to get setup.

                  Some good news though, it means that the TMS9911 from Littlediode are OK even if the TMS9909 from UTSource aren't.

                  I also fixed the random beeps, that was down to IC64, a 74LS259. Now replaced for the moment with a modern 74HCT259 as i only seemed to have had the one.

                  So, thanks again Dave for your utilitys, i'd not realised you'd updated the web site so much since i first saw it.

                  Jim
                  Last edited by Jim Hearne; November 16, 2012, 12:40 AM.

                  Comment


                    Nice progress! Well done - keep up the good work.
                    Torfinn

                    Comment


                      Great news Jim!!!!!!!!!!!!!!!!!!!

                      I'm glad all that stuff I did came to good use. It's nice to share. I only recently revisited my website and found a lot of the links to files broken. Not sure how that happened, it's like the Host deleted everything over a certain size. I have put everything back as it was but if anyone notices a problem let me know and I'll restore it again.

                      I think you'd be wise to look into getting a couple of 3.5" floppy drives in place of the 5.25" ones. It's been my experience that 3.5" drives are more stable when compared to the 5.25's and this helps with the somewhat unstable Double Density Data Separator circuitry. I recall at one stage I had a pot on the back of one of my computers that I sort of twiddled to find a sweet-spot for DD operation with some really old 80T, DSDD drives. If push comes to shove I can take a look to see what resistor values are in there now. I think I recommend a specific 3.5" model somewhere on the website? They just have to be capable of running at 300 rpm and have drive-select signals (and you need to cover up the HD hole on the diskettes).

                      Anyway, awesome news!

                      Dave.

                      Comment


                        Originally posted by tms9995 View Post

                        I only recently revisited my website and found a lot of the links to files broken. Not sure how that happened, it's like the Host deleted everything over a certain size. I have put everything back as it was but if anyone notices a problem let me know and I'll restore it again.
                        Looked into this. Turns out the 'free' web host I have been using has a policy whereby, at their discretion, they might delete files over 5MB. I wish I'd known about this as I would never have used them. I just wanted to get everything up on a website for everyone to share. Once it was up there and working, I didn't revisit it as I had no need to change anything.

                        Anyway, I have now moved to a paid host... I apologize for the broken links in the past year or so and hope that it is once again complete.

                        Dave.

                        Comment


                          Originally posted by tms9995 View Post
                          I think you'd be wise to look into getting a couple of 3.5" floppy drives in place of the 5.25" ones. It's been my experience that 3.5" drives are more stable when compared to the 5.25's and this helps with the somewhat unstable Double Density Data Separator circuitry. I recall at one stage I had a pot on the back of one of my computers that I sort of twiddled to find a sweet-spot for DD operation with some really old 80T, DSDD drives. If push comes to shove I can take a look to see what resistor values are in there now. I think I recommend a specific 3.5" model somewhere on the website? They just have to be capable of running at 300 rpm and have drive-select signals (and you need to cover up the HD hole on the diskettes).
                          Dave.
                          Ah, but 3.5" drives aren't correct for the Cortex are they.
                          I know, neither is the PC power supply it's currently running on but i'll replace it with a switcher at some point.
                          Spent a bit more time recently trying to get better quality video out of it, the TV out into a PC TV card is very poor, with certain colour combinations it doesn't manage to stay synced art all.
                          I've checked over the video signal into the modulator and it seems correct, i've checked the sync levels as mentioned in the newsletters but that all seems correct as well.
                          I changed the modulator in the end but no difference.
                          I think the next thing will be a RGB or component out interface.

                          Jim

                          Comment


                            Originally posted by Jim Hearne View Post
                            Ah, but 3.5" drives aren't correct for the Cortex are they.
                            Spent a bit more time recently trying to get better quality video out of it, the TV out into a PC TV card is very poor, with certain colour combinations it doesn't manage to stay synced art all.
                            I've checked over the video signal into the modulator and it seems correct, i've checked the sync levels as mentioned in the newsletters but that all seems correct as well.
                            I changed the modulator in the end but no difference.
                            I think the next thing will be a RGB or component out interface.

                            Jim
                            Your PC TV card no doubt supports composite NTSC. So you could replace the video chip with a 9918 which gives a direct composite output - it just needs a pull-down resistor on the video output. Pin compatible apart from (from memory) 3 pins, which you would have to bend out of the socket. Would probably need a different crystal as well, thinking about it.

                            There's also the new F18A video chip replacement board (http://codehackcreate.com/) which gives you a VGA output you can connect to another monitor.

                            Neither of these suggestions are correct for the Cortex though.

                            Stuart.

                            Comment


                              Originally posted by Stuart View Post

                              There's also the new F18A video chip replacement board (http://codehackcreate.com/) which gives you a VGA output you can connect to another monitor.

                              Stuart.
                              Nice find Stuart! I might be very tempted to get one of these (especially since I don't own a 'real Cortex' anyway ). Being able to use a regular monitor would be a bonus, and it adds the V9938 80 column mode which I use all the time.

                              Dave.

                              Comment


                                I have seen on ebay tim9904 described as 8 to 3 line encoder, having read that components from utsource are sometimes fake, do you think this is worth a try?

                                http://www.ebay.co.uk/itm/1209208399...84.m1438.l2649

                                Thanks.

                                Comment

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