Image Map Image Map
Page 1 of 3 123 LastLast
Results 1 to 10 of 23

Thread: Leading Edge Model M BIOS

  1. #1

    Default Leading Edge Model M BIOS

    I'm fixing up my families old Leading Edge Model M. I've had to clean up some battery leakage as well as replace a few chips, but the system is now booting just fine.
    The issue that I have come across is that I can't seem to get the computer to boot with any EGA or VGA cards. The selection of cards that I am currently using are:

    Paradise EGA Basic and the Orchid Designer 800. Both of these cards test fine in another computer that I have. I have a feeling that the BIOS that is in the computer ( (c) 1984 ) just doesn't support BIOS extensions.

    I have come across several mentions of needing to have version 4.71 of the Bios for MS-DOS 5.0, as well as being mentioned in another VGA installation manual.

    Questions:
    Does anybody know where I could perhaps find this version of the BIOS? Or do you think the Turbo XT BIOS project would help?

    Thanks in advance.

    -Huw

  2. #2
    Join Date
    Sep 2017
    Location
    Principality of Xeon
    Posts
    1,861
    Blog Entries
    1

    Default

    As I recall I was not able to use any 3rd party cards in my M either. Therefore the questionable Mobo I have won't be of any help I presume. But if you're interested in general parts, I have everything except the floppy drive. The Sperry equivalent was the HT XT or something like that. Search the archives, there have been mentions of the Sperry not long ago.

  3. #3
    Join Date
    Mar 2013
    Location
    Chaffee, MO
    Posts
    1,064

    Default

    Leading Edge Modem "M". Yep, I've got one, and I have upgraded the BIOS for EGA Support, as the Original BIOS didn't work with EGA.
    The ONLY Problem is I don't have that BIOS Chip with me, or I don't think I do. I'll have to Search my Hard Drive. I'm away from the
    Model M or I could pull the EPROM and Burn another copy. That was Years ago..............Mid 80's to early 90's. If I remember correctly
    that upgrade was a bit expensive at the time.

    Let me do a bit of searching. I burned the Replacement EPROM's at work. Maybe I have it on my old Partition. Otherwise it will be
    April 2019 before I can work on it.

    Thanks.

    Larry

  4. #4
    Join Date
    Mar 2013
    Location
    Chaffee, MO
    Posts
    1,064

    Default

    hupshall,
    You better run out and buy us two lottery tickets tonight. You just hit the LUCKY NUMBER............
    Code:
    ./386_C/CDR/M471.ROM -- BINGO
    Send me PM with your email address. I'm sure the Code is in HEX bytes, as my BP Microsystems EP1 used a serial
    port at 9600 and Hex bytes to program with. If you need it converted to Intel or Motorola, I'm sure Linux can convert
    it to what you need. I'll email it and you can burn it. I forget what manufacture type EPROM the Model M had, but you
    want to make sure the speed rating of the one you use is at least as fast, or faster than the original.

    I forget what EGA card I used but it worked Perfect. I converted 3 Machines back in the day.


    Thanks.

    Larry

  5. #5

    Default

    I'd be interested to know if the BIOS chip has a version # on it.

    My M is working fine with an XT-IDE - I have it booting and running with DOS 4.01 - I'm still digging through boxes trying to find my old MS-DOS 5.0 360k floppies
    I also have a really old school IBM Color Graphics CGA card in it so I have a display - But the long term goal would be 16 colors.

  6. #6

    Default

    Thanks Larry.

  7. #7
    Join Date
    Mar 2013
    Location
    Chaffee, MO
    Posts
    1,064

    Default

    hupshall,
    It looks like it's a 1K EPROM. I don't remember if it was 24 or 28 Pin. You probably already know that.

    Code:
    00000000   42 30 34 46  30 34 30 30  30 30 30 30  30 30 30 30  B04F040000000000
    00000010   30 30 30 30  30 30 30 30  30 30 30 30  30 30 30 30  0000000000000000
    00000020   0D 0A 45 39  39 35 30 30  45 39 43 33  30 31 46 46  ..E99500E9C301FF
    00000030   46 46 46 46  46 46 46 46  46 46 46 46  46 46 46 46  FFFFFFFFFFFFFFFF
    File Size is:
    34818 Jan 1 20:08 M471.ROM

    34818 / 32 = 1088

    1088 * 2 = 2176

    64 blocks of 32 bits plus 0x0D 0x0A (128 of these) - 2048 + 128 = 2176

    1K EPROM

    What format do you need it in? Right now, it's in HEX BYTES. Two bytes make up a HEX byte. 42 = B and 30 = 0
    So, the first byte in the EPROM is 0xB0.

    I am pretty sure I can change it to Intel, Motorola, or the format you need.

    I have no other information for it right now.

    Thanks.

    Larry

  8. #8
    Join Date
    Jan 2013
    Location
    Marietta, GA
    Posts
    2,951

    Default

    I'd suggest sending a copy of that ROM to Modem7, for addition to his PC BIOS ROM page: http://www.minuszerodegrees.net/rom/rom.htm

  9. #9
    Join Date
    Mar 2013
    Location
    Chaffee, MO
    Posts
    1,064

    Default

    SoneGuy,
    Sure, that is a good idea. But, no where on that site does he have a address for contact posted. How does one find his email address.
    I know I've emailed him before with other BIOS ROM's I had saved, but I forget his name.


    Larry

  10. #10
    Join Date
    May 2006
    Location
    Melbourne, Australia
    Posts
    6,117

    Default

    Quote Originally Posted by SomeGuy View Post
    I'd suggest sending a copy of that ROM to Modem7, for addition to his PC BIOS ROM page: http://www.minuszerodegrees.net/rom/rom.htm
    Quote Originally Posted by ldkraemer View Post
    Sure, that is a good idea. But, no where on that site does he have a address for contact posted.
    I have no contact details there in order to stop a never-ending barrage of IBM 51xx questions (and advice on how to make my site better).
    I want people with questions to come here instead, hence my "For queries or assistance, I suggest ..." text on the root page.

    Quote Originally Posted by ldkraemer View Post
    How does one find his email address.
    Via the PM that I see that you subsequently sent.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •