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Thread: iBM PC XT - RAM Issue

  1. #1
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    Default iBM PC XT - RAM Issue

    I havent opened it up yet as I wanted to ask....

    My IBM 5160 PC XT on boot is now only counting 256K of RAM instead of 640K like it should be. The machine and IBM Monitor has not been moved, bumped / etc and all the sudden started booting up like this, causing other software to not load....The Hard Drive loads afterward as it should and everything else seems fine...

    What would be some things to look at inside to find out what is going on? I can make sure the chips are seated properly, but I dont know how they'd get loose as it hasnt been moved or anything....

    Thanks ahead of time!!!
    "In Life, The Days Are Long But The Years Are Short..."

  2. #2

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    How much ram is on the motherboard. (Sounds like 256k)

    If so, is there a ram expansion card? If so, check its seating in the slot by removing and reinserting it.

    It sounds like the board counts all the ram it knows about and then just ignores a ram expansion card.

    Loose chips isn't as likely as corroded contacts.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  3. #3

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    How much RAM is on the mainboard? I guess that's the first bit of important info

  4. #4
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    Default

    640K on the Board
    "In Life, The Days Are Long But The Years Are Short..."

  5. #5

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    That would mean only the first memory bank is counted/detected. I guess a chip in the second bank could have died, or the pins of a chip could be corroded.

    But why don't you get an error message, if four banks are enabled (through the DIP switches), and only one bank is detected?

  6. #6

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    Is this a 256k board that you modded for 640k?
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  7. #7
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    Default

    "In Life, The Days Are Long But The Years Are Short..."

  8. #8

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    There might be a bad chip in bank 1. Try substituting for these chips to determine if that's the case.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  9. #9

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    Read here: http://www.minuszerodegrees.net/5160...ems_issues.htm

    You most likely have a problem in memory bank 1 (second bank). Try re-seating the chips, or replace them one at a time with a new chip, until the problem goes away.

  10. #10
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    Default

    Gonna give this a shot tomorrow....thanks for the recommendations
    "In Life, The Days Are Long But The Years Are Short..."

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