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  1. Yes, N*H cards were available as kits. Just...

    Yes, N*H cards were available as kits.

    Just checkout one of the floppy disks. If memory serves me correctly, they were hard sectored - and the chance of buying hard sectored disks today is...
    ...
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    And to fill in a bit of firmware details for you:...

    And to fill in a bit of firmware details for you:

    The reset vector is in the very top memory locations of the kernal ($Fxxx) ROM. This vectors to the start-up code (that is also located within the...
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    If you look here...

    If you look here http://www.6502.org/mini-projects/nop-gen/nop-gen.htm you will find a design for a NOP generator. However, it’s not the easiest page to understand! You have two options (a) buy a...
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    I can certainly look at adding a CRC-16 (as well...

    I can certainly look at adding a CRC-16 (as well as a checksum) to the display. I can't promise when though. If I get bored of reviewing documents at work it could be a bit of light relief of course...
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    The manual tells you how to interpret the error...

    The manual tells you how to interpret the error message.

    MEM FAIL 3 1 0C80 10 FF

    The '10' indicates the bit in error. One (and only one) bit will be set.

    The 'FF' indicates the value (byte)...
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    Does your oscilloscope have an earth connected to...

    Does your oscilloscope have an earth connected to the probe screen that you are connecting to the PET's 0V/GND?

    If so, what you may actually be measuring is a mains earth loop as opposed to a real...
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    We seem to be ‘flipping’ from one thing to...

    We seem to be ‘flipping’ from one thing to another without actually chasing down any actual problem.

    The common theme seems to be power supply. So, as Dwight has suggested, let’s run this to...
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    If it is the capacitor I am thinking about, this...

    If it is the capacitor I am thinking about, this capacitor is before the voltage regulators. There will be about 9 Volts or so here. You are in the UK (so 50 Hz mains supply) full-wave rectified will...
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    Just to confirm, the checksums I obtained were...

    Just to confirm, the checksums I obtained were using the Zimmers images with VICE running my PETTESTER in the EDIT ROM socket. It is possible that I mistyped the checksum into the manual. VICE also...
  10. It’s almost as though the images you are using do...

    It’s almost as though the images you are using do not have the correct device drivers for the card.

    Could I suggest using the images found on the RCB site, just to see if there is any difference...
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    Yes, the initial page appears to have some...

    Yes, the initial page appears to have some extraneous ".." and "K@B" which is clearly wrong. However, the initial tests (which passed) checked out the video RAM - so the errors are probably 'video...
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    Good spot about the pk-pk noise Dave - I missed...

    Good spot about the pk-pk noise Dave - I missed that...

    So, there is nothing fundamental wrong if you can get someone else's PETTESTER to work. We just have to smoke out the metal mouse...

    Dave
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    Usual things after the power supply are: Do...

    Usual things after the power supply are:

    Do you have a clock on the CPU pin 39? You should see a 1 MHz clock.

    Is the CPU in a permanent reset - check CPU pin 40. Pin should be HIGH. However, on...
  14. As Dave says, you should just see the clock on...

    As Dave says, you should just see the clock on pin 9 of the CPU.

    From what I remember, the HD-6120 was only specified at up to 5.1 MHz; so 8 MHz may be overclocking it. Drop the oscillator to 5...
  15. Yes. Firstly, are the power supplies OK. ...

    Yes.

    Firstly, are the power supplies OK.

    Secondly, is the CPU in a permanent RESET and is it executing instructions at all?

    What test equipment do you have?

    Dave
  16. I guessed as much! I must try and find my SBD...

    I guessed as much!

    I must try and find my SBD DMA driver for you. I will have it on a disk somewhere.

    It is not for a DEC operating system - but the underlying implementation is the important...
  17. There does seem to be references to...

    There does seem to be references to multi-terminal support via the XL driver.

    See the RT-11 System Internals manual Chapter 4.

    Unfortunately, I don't think it is as nice or easy as you think to...
  18. First things first. Are your other serial...

    First things first.

    Are your other serial ports on the DLV11-J available to RT-11?

    If not - they can't be used until they are.

    LUN 5 is the 'standard' terminal (TT input) and LUN 7 is the...
  19. It might be worth an e-mail to Iomega (now...

    It might be worth an e-mail to Iomega (now LenovoEMC). You never know...

    Dave
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    After reviewing the photograph, I would get some...

    After reviewing the photograph, I would get some flux remover and clean away all of the remaining flux residue around the solder joints.

    Even if it isn't a problem for now, it could be in the...
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    Pin 3 is N.C. (no connect) so that is right. ...

    Pin 3 is N.C. (no connect) so that is right.

    Pin 37 is the input clock (PHI0) so that is right.

    Pin 39 is the output clock (PHI2) so that is right - but without a 6502 CPU in place there is no...
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    There is something not right here. I think we are...

    There is something not right here. I think we are doubling-back on ourself...

    This logic probe should be able to resolve the frequencies we are talking about on the PET.

    Pin 7 of the VRAM is...
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    Pins 1 and 2 should definitely not be high - they...

    Pins 1 and 2 should definitely not be high - they should be pulsing. However, these two pins are the highest-frequency pulses than the others - and it could be that this is confusing your logic...
  24. Hey Mike, nice job... I would be in the market...

    Hey Mike, nice job...

    I would be in the market for both a green and amber - but live in the UK. If anyone else from the UK wants to 'chip in' then we could split the shipping between us?

    I am...
  25. Thread: Micro PDP 11/73

    by daver2
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    Gary, I hope this isn't the PDP-11 we have...

    Gary,

    I hope this isn't the PDP-11 we have been trying to find for 2 years now...

    It was 'put away safely' by someone on site - never to be found again :-)!

    Dave
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