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Thread: Com port not detected

  1. #1
    Join Date
    Apr 2019
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    Default Com port not detected

    Does anyone know anything about this card? It came with my Compaq Portable and seems to be a COM port.

    The compaq diagnostics do not detect a com port installed though... I am not sure what jumper settings are needed (or if that is the problem).

    Someone else seems to have done some board repair on it as there are a couple wires soldered on.

    IMG_20190716_005948.jpg

    IMG_20190716_010004.jpg

    IMG_20190716_005956.jpg

    IMG_20190716_005948.jpg

  2. #2

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    Soldered on wires doesn't necessarily indicate a repair. Plenty of boards leave the factory this way.

    This does not look like an RS232 card to me.

  3. #3

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    did you lookup all the chips? It does seem to have a serial controller on it. The Intel D8274.

    Maybe itís a proprietary card for some external device? Thatís a heck of a lot of DIPs to manage one COM port

  4. #4
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    Default

    2 RAM chips and a high speed multi-port serial chip plus whatever the large NEC chip is (I can't read it) suggests buffering for multiple devices.

    Probably needs a special driver to do anything.

  5. #5

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    Quote Originally Posted by KC9UDX View Post
    Soldered on wires doesn't necessarily indicate a repair. Plenty of boards leave the factory this way.
    Concur. Board revisions and fixes usually wind up getting modifications after they're completed. Sometimes design-engineers find better ways of doing something after manufacture or PCB routing just doesn't pan out the way they thought. We had many designs at Siemens with such a fix.

  6. #6
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    Default

    Thanks for all the replies guys, I looked at a few other com/serial boards and it does look like it is much more complicated than a typical serial only board.

    I will talk to person I received the computer from and see if I can jog his memory some more.

    There are no markings on the other side, but the board traces are also all "wrinkled" for lack of a better word. They still look ok but definitly not something I have seen before.

  7. #7
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    Quote Originally Posted by krebizfan View Post
    2 RAM chips and a high speed multi-port serial chip plus whatever the large NEC chip is (I can't read it) suggests buffering for multiple devices.

    Probably needs a special driver to do anything.
    The only identification I can see on the board is IBM DE-1A but I haven't been able to look that up.

    The large NEC chip is an 8085.

  8. #8
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    Default

    I'm going to guess maybe a network card, or perhaps a terminal interface card for a mainframe system ... is the connector db9? male or female?

  9. #9
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    Default

    That large NEC chip is an 8085 CPU. This isn't a simple comms card.

  10. #10
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    Jan 2019
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    New Hampshire
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    Default

    What is written on the ROM(?) chip next to the 8085?? Anything on the back of the board?

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