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Thread: 1M x 1 DRAM

  1. #1
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    Default 386 Board with 8 1Mx9 30 Pin SIMMS

    Is 1M X 1 DRAM useable in a PC?

    Curious as I am not sure I've seen this designation before or I am just looking at it wrong and it's just a normal 1 MB Stick of DRAM with 9 1Mx1 chips on it?

    Have a 386 board I got that I cannot get to post and it has 8 of these in it. 9 1Mx1 chips on one 30 pin SiMM
    Last edited by Smack2k; March 31st, 2017 at 06:18 PM.
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  2. #2
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    The early 1 MB SIMMs would have 8 or 9 such chips.

  3. #3
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    A 1Mbit x 1 DRAM would be something like an NEC µPD421000, OKI MSM511000, or Toshiba TC511000 chip. You would need 9 of them to make a 1MB SIMM with parity.

    You couldn't use a single chip by itself for normal RAM in a PC.

  4. #4
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    I have 8 of these in the board (1Mx9) and it will not post. I have removed every card from the board, tried different video cards as the only card plugged in and nothing. Was thinking maybe the RaM was the issue.
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  5. #5

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    You only need 4 sticks to populate a bank.

    You only need one bank to run the board.

    If you have 2 bad sticks, 1 in each bank, both banks will fail, so it's possible (but not certain) you have 6 good sticks.

    If you have 7 good sticks and the bad stick is in bank zero the board will not run.

    Try with just 4 sticks in bank 0. Keep replacing 1 then 2 at a time using all possible combinations and you might get lucky.

    It would certainly be much easier if you have a 386SX or a 286 board as these only have 2 sticks per bank and the odds of getting lucky would be much greater.
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  6. #6
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    If it is a 386 motherboard it probably needs memory to be installed in banks of four 1Mx9 SIMMs to get a 32-bit wide memory system, so either four SIMMs total in one bank or eight SIMMs total in two banks.

    If you have only been trying with all eight SIMMs installed maybe try with just four matched SIMMs installed in bank 0, or however the first bank might be labeled, or try swapping though different SIMMs in the four you are trying together.

    Don't have any other obvious ideas to try.

    (edit: Stone and myself typing basically the same things at the same time )

  7. #7

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    Quote Originally Posted by gslick View Post
    (edit: Stone and myself typing basically the same things at the same time )
    Ya', I usually draw Chuck as a typing partner but tonite the lottery was different.
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    Well, for what it's worth, I still have a 386 board or two that takes the 1Mx1 DIPs. Mine are all Hyundai branded. No problems for years.

  9. #9

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    And I have a 286 board that takes the 1Mx1 DIPs.
    PM me if you're looking for 3½" or 5¼" floppy disks. EMail “ ” For everything else, Take Another Step

  10. #10
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    I will give the RAM tests a try....

    I mis-spoke on the RAM...they are 1Mx9 chips....there are 8 of them....it was late last night when I was looking at them!!

    I noticed that the RAM types had some of each in each bank (2 Toshiba and 2 Siemens in Bank 0 and 2 of each in Bank 1) I will try them with similar in each bank and then begin the process of testing each chip by itself in slot 1 Bank 0 to see if one is bad...

    Could the cache be an issue to? If the jumpers are set wrong (I dont think they are, but need to check later today) and there is 256K in the board but the jumpers are set to, say, 64K, could that cause the same issue where it wont even post?
    "In Life, The Days Are Long But The Years Are Short..."

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