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Powertran Cortex

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    Hurray! one bad byte can spoil the barrel. (sorry O/T - apple related)

    Is it supposed to beep on power up at all? mine doesn't - strange but I can't find the speaker/piezo at all on the diagrams.
    "Don't it always seem to go
    That you don't know what you’ve got ‘til it’s gone" (BANG )

    Comment


      Nige, I think the piezo is labelled as "BELL" on IC64 (Q6) - See ETI - Cortex part 2, Fig 1 (Circuit diagram for keyboard and control port)
      On the board it's located 3 x IC sockets to the right of the +12 volt input lead.

      Comment


        There's a slightly fried but nevertheless functional resistor attatched to the "piezo" terminals on mine. It's not there anywhere on the cct diags.
        Other half of the question - does it beep on power up? (mine doesn't) it's a bit easier than trying to get it to beep in basic to ascertain functionality of the speaker.
        It could be like the lack of sync problem I had - which turned out to be the fault of the TV, not the computer.
        "Don't it always seem to go
        That you don't know what you’ve got ‘til it’s gone" (BANG )

        Comment


          My Cortex doesn't beep at start up either but if you want to test the speaker press the "rub out" key. If you haven't entered any text it will beep each time you press it.
          On mine the two piezo circuit board contacts are for the leads to the piezo, the only resistor is to the right of these contacts. = R45

          Comment


            Nige/Andy,

            I got all warm and fuzzy inside knowing that, out of this, not one but two Cortex's have been brought back to life and we got a copy of Forth as well! Great work to all involved.

            Comment


              not saying too much yet.... but mine went totally unstable, I got to test the speaker (continuous beep) I've done some reseating, and it now seems ok. But I'm keeping my fingers crossed until it boots 50 times on the run & from cold too.
              I'm hoping it isn't something funny like an earthing problem, Ive put all the screws in that it looks like it should have.
              I'm waiting for an order to turn up, hopefully with the mains switch in. then I can put it together properly again.
              Last edited by nige the hippy; April 3, 2010, 08:51 AM.
              "Don't it always seem to go
              That you don't know what you’ve got ‘til it’s gone" (BANG )

              Comment


                I'll try and get the updated ROM images up on WHTech sometime this week. I've been pretty busy at school this month, so I've been totally quiet otherwise. . .
                Enter My Mind At Your Own Risk!

                Comment


                  Excellent news Andy!

                  Stuart.

                  Comment


                    Nige, A quick correction to my earlier post, the speaker is shown on "fig 2 Circuit Diagram of the RS232 and cassette interfaces".

                    I'm currently having fun and games trying to recover my Cortex programs from the old cassette tapes.
                    After trying several cassette players and having the dreaded mains hum and frequency equalisation destroying the waveforms, I have now found an old dictaphone (battery operated). This basic player seems to have just the bare minimum of amplifiers to replay rather than destroy the original info.
                    When I've got them into WAV format, I'll post them on the forum.

                    Comment


                      AAAAHH! Kind of pencilled in as an afterthought!

                      Mine seems to be stable & nice now. I've put a good little mains switch on the back & screwed it mostly together. I was just on the point of putting the top on when I noticed the frayed disk connector, so it's another hunt in the shed for another, or buy a spare 34 way idc connector & splice it on the good side of the fray.
                      "Don't it always seem to go
                      That you don't know what you’ve got ‘til it’s gone" (BANG )

                      Comment


                        A quick question to all of you using a Cortex with an old analogue TV.
                        Is your screen display to far to the left?
                        I am unable to see the very first character on the left hand side of the screen and my TV doesn't have the luxury of a manual adjust.
                        How do you think I can overcome this - Is it likely to be a circuit problem or a modulator problem - Any ideas?
                        It's not terribly important, but it is annoying - I've tried several different TVs and the're all the same.

                        Comment


                          Might one of the TVs have an internal adjustment pot on the PCB? If you have a friendly local traditional TV repair shop they might be able to advise.

                          (Usual disclaimers about electrocuting yourself apply)

                          Originally posted by andyp View Post
                          A quick question to all of you using a Cortex with an old analogue TV.
                          Is your screen display to far to the left?
                          I am unable to see the very first character on the left hand side of the screen and my TV doesn't have the luxury of a manual adjust.
                          How do you think I can overcome this - Is it likely to be a circuit problem or a modulator problem - Any ideas?
                          It's not terribly important, but it is annoying - I've tried several different TVs and the're all the same.
                          Last edited by Stuart; April 9, 2010, 01:15 PM.

                          Comment


                            Now that's strange.... I put it down to the TV, but perhaps it isn't. There's also a little visible flyback line diagonal top right hand side. I wonder if it was a bug.
                            "Don't it always seem to go
                            That you don't know what you’ve got ‘til it’s gone" (BANG )

                            Comment


                              Originally posted by nige the hippy View Post
                              There's also a little visible flyback line diagonal top right hand side. I wonder if it was a bug.
                              Tried tweaking pot R37 on the video output stage?

                              Comment


                                That was the first thing I did. it seems to adjust mostly the contrast, and finally the sync gives up. (although I'll re-ascertain that)
                                "Don't it always seem to go
                                That you don't know what you’ve got ‘til it’s gone" (BANG )

                                Comment

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