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Type: Posts; User: MikeS

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  1. :rofl:

    :rofl:
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    That's what I thought ;-) Indeed; VP is the...

    That's what I thought ;-)


    Indeed; VP is the main battery voltage; PCS (not PC3) is the low power shutdown signal from the CPU through the PIA (pin 33)

    A good writeup in the service manual pp....
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    The jack includes a switch to disconnect the AA...

    The jack includes a switch to disconnect the AA primary (non-rechargeable) batteries when the adapter's plugged in.

    Service and Tech ref manuals here:
    http://www.club100.org/library/libdoc.html
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    The first digit is the year (1983 or 1984) and...

    The first digit is the year (1983 or 1984) and the next two are the month; somewhere around October 1983 (310xxxxxx) the board was changed to use a JEDEC 'standard' 27C256-compatible system ROM...
  5. [QUOTE=WSM;590241]MikeS: A simple PLD solution...

    Sounds like we're on the same track, although the EPROM wouldn't (need to?) latch the keypress values.

    Either way, I think it would be trivial to implement on a cheap single chip once you've...
  6. Why not? Unless I'm missing something the old...

    Why not? Unless I'm missing something the old keyboard can generate part of the 12-bit address and the 'new' scan lines the rest, and one of four output bits goes to the 'input' (this assumes the...
  7. As Chuck says, we need to know how the keys are...

    As Chuck says, we need to know how the keys are scanned; I doubt that it's as straightforward as 8 inputs to 7 outputs, more like converting 4 outputs and 3 inputs to 3 outputs and 5 inputs or vice...
  8. Assuming that you're dealing with TTL levels and...

    Assuming that you're dealing with TTL levels and the matrix is scanned the usual way you should be able to do this with a small EPROM.
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    Enjoy! Just curious, Dave: do you have a...

    Enjoy!

    Just curious, Dave: do you have a working dynamic RAM PET?
  10. Thread: 8050

    by MikeS
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    FYI, there are four versions of the 8050, with...

    FYI, there are four versions of the 8050, with different drives and ROMs; it might be useful when troubleshooting to identify which version you have from the numbers on the ROMs.
  11. Security dongles using the cassette port were...

    Security dongles using the cassette port were fairly common; I've got a couple myself somewhere (but not for Wordcraft ;-) ).

    Tying up the cassette port was not a big issue since the programs that...
  12. What is the PC board number? There are at least...

    What is the PC board number? There are at least three different versions of that board.
    Video J7:
    1 Video
    2 Gnd
    3 Vert. Drive
    4 Gnd
    5 Horiz. Drive
    6 Missing
    7 Gnd
  13. Hello and welcome! If I may make a suggestion:...

    Hello and welcome!

    If I may make a suggestion: when trying to diagnose remotely details are very important; I suspect the numbers on those ICs are really 901447-10 (character generator) and...
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    Umm, that was my (tongue-in-cheek) point:...

    Umm, that was my (tongue-in-cheek) point:
    https://en.wikipedia.org/wiki/Tandem_Computers
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    Many Tandons need​ a magnet to function... ;-) ...

    Many Tandons need​ a magnet to function... ;-)

    Or did you perhaps mean that line of fault-tolerant computers?
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    IDE: Integrated Drive Electronics (Hard drives,...

    IDE: Integrated Drive Electronics (Hard drives, CD & DVD drives etc.)
    IDC: Insulation-Displacement Contact (Connectors and cables).

    So, most IDE cables are also IDC cables, but not necessarily...
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    @ Fran: do you (or a friend) have the means to...

    @ Fran: do you (or a friend) have the means to burn Dave's diagnostic ROM into a 2716/2732/2532 EPROM or equivalent?
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    Nah; not enough Daves like the two in this thread...

    Nah; not enough Daves like the two in this thread and Dave Curran ;-)
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    True, but it looks like RAM and ROM might be...

    True, but it looks like RAM and ROM might be fine; it might be informative to write directly to the screen as Dave's PETTEST does, without relying on RAM and the standard E ROM and the various...
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    That's what I've been wondering throughout this...

    That's what I've been wondering throughout this most informative technical thread: does the OP have a diagnostic ROM or the means to make one, and if so did we see the output anywhere along the way?
  21. Same here. Aside from the odd SCR and those...

    Same here. Aside from the odd SCR and those crappy buttons on the wireless remotes I haven't had many problems in more than thirty years; 95% reliability's good enough for me and they've solved quite...
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    Have you got the whole tech manual or just a...

    Have you got the whole tech manual or just a schematic?



    Do either of those machines have a cassette drive?

    Many years ago, before I realized that people actually collect this old junk, I...
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    Not NCR, but I have a bunch of Burroughs...

    Not NCR, but I have a bunch of Burroughs cassettes (the same type as above) containing L Series utilities and applications, and also a working drive. ISTR that you were planning to come up with...
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    Note that if you hold the DIAGNOSTIC line low...

    Note that if you hold the DIAGNOSTIC line low while resetting you will enter the monitor instead of doing a full reset. See:
    http://www.6502.org/users/andre/petindex/repairs.html

    There's also...
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    Not sure what you mean; the relevant pins of the...

    Not sure what you mean; the relevant pins of the socket are bent out and up and connected appropriately (with a piece of paper underneath to prevent the bent out pins from touching the system...
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