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Thread: MDA on my IBM XT

  1. #1

    Default MDA on my IBM XT

    Maybe I have a problem with my MDA Card...?!
    When I power on my XT I have a long beep and two short beep... but then it starts and all work very good.
    SW1 switch 5 and 6 are OFF as required. I have replaced all tantalum on MDA and the ISA connector is perfect, can you help me?
    Thank you very much from Italy

  2. #2
    Join Date
    May 2006
    Location
    Melbourne, Australia
    Posts
    6,227

    Default

    Quote Originally Posted by p.giaquinto View Post
    Thank you very much from Italy
    You can put "Italy" into the 'location' part of your profile, via [My Profile]/[About Me]/[Location].

    Quote Originally Posted by p.giaquinto View Post
    SW1 switch 5 and 6 are OFF as required.
    From what I know of the IBM XT (IBM 5160), I can rule out dirty/broken switches (that would cause other symptoms).

    But if you want to check out the switches, there is test procedure at:
    1. Goto http://minuszerodegrees.net/index.htm
    2. Navigate to the [IBM 5160] section.
    2. Click on [Test of SW1 via BASIC] link.

    Quote Originally Posted by p.giaquinto View Post
    Maybe I have a problem with my MDA Card...?!
    Your question tells us that you do not have a second MDA card.

    What does CheckIt diagnostics software think about the card? Navigation within CheckIt: [Tests][Video]

  3. #3

    Default

    Checkit 2.1 has encountered 16 ERRORS on video RAM test!
    Parity error at address (Bits BA9:
    0B0000h
    0B0002h
    0B0004h
    0B0006h
    0B0008h
    0B000Ah
    0B000Ch
    0B000Eh
    0B0010h
    0B0012h
    0B0014h
    0B0016h
    0B0018h
    0B001Ah
    0B001Ch
    0B001Eh
    All other tests are OK. Must I replace some chips on my MDA card?
    Thank you for your help, I hope to solve

  4. #4

    Default

    I’d pretend it’s 1985 and replace it with a Hercules

  5. #5

    Default

    AFAIK the MDA card has 1k*4 SRAMs on board and therefore has no parity RAM. The monochrome cards that I know of that have DRAMs onboard are MGP cards, Monochrome Graphic and Printer card, capable of displaying graphics, therefore the 64 KB of RAM.
    Second thought: do MGP cards have a parity check at all ??? (not at home, cannot look for myself now)
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  6. #6

    Default

    Solved replacing all 9114 RAM with new working 2114

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