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Thread: Seeking memory card for InBoard/386

  1. #1

    Exclamation Seeking memory card for InBoard/386

    OK, ultra long shot that someone might have or know of an available 2MB or 4MB expansion piggyback/expansion board for an Intel Inboard/386...

    I know, the lottery might have better odds, but it never hurts to ask!

    Regard,
    Mike

  2. #2

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    I think trying to find an piggyback / expension board is actually a no-go.. They are seem to hard as hell to find those these days..

    Maybe i can help with this (worth trying)
    http://www.ebay.nl/itm/INTEL-INBOARD...item19f6e9148f
    THE BIOS MASTER

  3. #3

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    I've got the 1M base InBoard/386 PC board installed and working. I just missed out on a 2MB piggyback expansion board for the Inboard last month on eBay - Aeeeeeiii!!



    Thanks,
    Mike

  4. #4

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    Im working on a pinout and schematic for a 2mb board and possibly even a 8mb board if i can get 4mb to work.
    Its not really that complicated, just a lot of work

    My last wire wrap prototype got to 1mb before i accidentally ripped some wires away.
    It was too much work to repair this and i will make a pcb with 8mb dram and a small proto-area.

    The 4bits of checksum are a pain and i will try to get around this with either a inboard-mod or a simulated crc check.

    But don't expect anything this year...

    -Jonas

  5. #5

    Default

    Nice to hear you have got some good result over there..
    THE BIOS MASTER

  6. #6

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    Quote Originally Posted by stynx View Post
    Im working on a pinout and schematic for a 2mb board and possibly even a 8mb board if i can get 4mb to work.
    Its not really that complicated, just a lot of work

    My last wire wrap prototype got to 1mb before i accidentally ripped some wires away.
    It was too much work to repair this and i will make a pcb with 8mb dram and a small proto-area.

    The 4bits of checksum are a pain and i will try to get around this with either a inboard-mod or a simulated crc check.

    But don't expect anything this year...

    -Jonas
    An 8M add would be awesome! Would love to see that working.

    Regards,
    Mike

  7. #7

    Default

    Quote Originally Posted by Robin4 View Post
    Nice to hear you have got some good result over there..
    define 'good results'

    I have acquired a logic probe that will help me to debug the expansion connector. But the probe does not have a "clock in" ... that makes things a lot more problematic. The probe can monitor 16 channels at up to 16 mhz, 9 channels at up to 32mhz, 6 channels at up to 50mhz and 3 channels at up to 100mhz. BUT my inboard only allows me to use an oscillator of 22mhz or higher. That means 11.xx mhz effective cpu clock. I have problems to get accurate measures of the HIGH and LOW at 16mhz sample rate. I have tried a sample rate of 100mhz and encountered some irregularities with my previous measure that make my data more or less unusable. I need 12 channels with a sample rate of at least 60mhz to get usable results... right now my only chance is to get the cpu-clock to 8mhz that i can sample at 16mhz (should be more or less usable).

    I don't want to spend another $500 for a 100Mhz 16 channel logic probe (right now).

    Measures of the Signals while booting (inboard386 memtest)
    Inboard386_XMS_memtest.jpg
    Image on flickr

    It would be nice if anyone who has some insight into memory timings and knows how to put the info into perspective would comment on this.

    -Jonas
    Last edited by stynx; November 16th, 2014 at 02:17 AM. Reason: Image added

  8. #8

    Default

    Measures of the Signals while booting (inboard386 memtest)
    Inboard386_XMS_memtest.jpg
    Image on flickr

    It would be nice if anyone who has some insight into memory timings and knows how to put the info into perspective would comment on this.

  9. #9

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    Well, I got my hands on a 2M piggyback card but not by itself. The last one that appeared on eBay went for a whopping $400. So I spotted a complete Intel Inboard 386/PC for sale with a 2M piggyback daughter card for $78 which was bid up to $260 - still expensive but I plan to keep that one and sell my existing Inboard/386 PC without a daughter card as a complete package (cable, drivers, doc, packaging and a 386 math co-processor, tested and verified) on eBay to offset the cost. I am not sure what it should sell for - there is one for sale on eBay now for $250 not as complete as the one I plan to sell, but that's a pretty good price given earlier ones went for quite a bit more.

    Regards,
    Mike

  10. #10
    Join Date
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    Default

    Is there a good photo of this inboard and its memory expansion available somewhere? Maybe a memory controller could be identified which has a datasheet.

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