schuster@dasys1.UUCP (Michael Schuster) (08/12/88)
In article <927@orion.cf.uci.edu> cain@bonnie.ics.uci.edu (Timothy Cain) writes: > >Does anyone have or know where I could obtain an IBM PC ROM BIOS >Upgrade Kit, part number 1501005? My neighbor needs one desperately Related subject: does anyone know what kind of ROM was used in the original IBM PC (not XT) of which this is a replacement? By this I mean, not the IBM part number but the generic ROM type. Put another way, what type of BLANK (EP)ROM could be burned and put into that socket? 2764? 2532? -- l\ /l' _ Mike Schuster {sun!hoptoad,cmcl2!phri}!dasys1!schuster l \/ lll/(_ Big Electric Cat schuster@dasys1.UUCP l lll\(_ New York, NY USA DELPHI,GEnie:MSCHUSTER CIS:70346,1745
davidsen@steinmetz.ge.com (William E. Davidsen Jr) (08/17/88)
In article <5962@dasys1.UUCP> schuster@dasys1.UUCP (Michael Schuster) writes: | Related subject: does anyone know what kind of ROM was used in the | original IBM PC (not XT) of which this is a replacement? By this | I mean, not the IBM part number but the generic ROM type. Put another | way, what type of BLANK (EP)ROM could be burned and put into that socket? | 2764? 2532? Fact: the PC tech ref says the part is 8k x 8 in size. Recollection: I think you can make an exact duplicate using a 2764. However, there are two address pins switched, so you can't easily burn a modified version. I remember seeing an adaptor used to allow burning a new ROM with a standard PROM burner. -- bill davidsen (wedu@ge-crd.arpa) {uunet | philabs | seismo}!steinmetz!crdos1!davidsen "Stupidity, like virtue, is its own reward" -me
davidsen@steinmetz.ge.com (William E. Davidsen Jr) (08/17/88)
In article <5962@dasys1.UUCP> schuster@dasys1.UUCP (Michael Schuster) writes: | Related subject: does anyone know what kind of ROM was used in the | original IBM PC (not XT) of which this is a replacement? By this | I mean, not the IBM part number but the generic ROM type. Put another | way, what type of BLANK (EP)ROM could be burned and put into that socket? | 2764? 2532? First, my old tech ref says the ROM is 8k x 8, so I think that's 2764. The part I'm not sure about is if there are two address pins flipped on the ROM, such that it can be read in order only in a modified socket, although it could be duplicated in a standard PROM burner. I seem to remember seeing a socket and plug with a lot of wires connecting them, which switched the two pins back. I am not sure about this, so don't waste your electrons flaming me if that's not the way it is. -- bill davidsen (wedu@ge-crd.arpa) {uunet | philabs | seismo}!steinmetz!crdos1!davidsen "Stupidity, like virtue, is its own reward" -me
schuster@dasys1.UUCP (Michael Schuster) (08/19/88)
In article <11872@steinmetz.ge.com> davidsen@crdos1.UUCP (bill davidsen) writes: >In article <5962@dasys1.UUCP> schuster@dasys1.UUCP (Michael Schuster) writes: > >| Related subject: does anyone know what kind of ROM was used in the >| original IBM PC (not XT) of which this is a replacement? By this > > First, my old tech ref says the ROM is 8k x 8, so I think that's 2764. >The part I'm not sure about is if there are two address pins flipped on >the ROM, such that it can be read in order only in a modified socket, >although it could be duplicated in a standard PROM burner. I've been told the original EPROM had a Motorola pinout, and that a 68764 or 68766 would work. These are 24-pin devices (like IBM's). I don't think a 2764 would work in any configuration (read or write), as it's a 28 pin device. Both devices are still listed by the big mail-order houses (Jameco and the like). Anyone happen to have a pinout? -- l\ /l' _ Mike Schuster {sun!hoptoad,cmcl2!phri}!dasys1!schuster l \/ lll/(_ Big Electric Cat schuster@dasys1.UUCP l lll\(_ New York, NY USA DELPHI,GEnie:MSCHUSTER CIS:70346,1745
dale@zippy.wustl.edu (Dale Frye) (08/19/88)
The EPROM to use is Mototola MCM68766. I bought some from Hamilton-Avnet. Cost about $5 - $10 each. This is a 24 pin EPROM. Most 8K EPROMS are 28 pin. 1: Don't copy the XT BIOS. It won't work in the PC. 2: Only the BIOS needs to be copied. It is the ROM on the extreme right looking in from the front of the machine. The other ROMS are for BASIC. 3: Some PROM programmers may not be able to read the original ROM. The chip select pin of the rom must be strobed with each data access. Many burners don't do this. I had to write a little program to read the ROM in the machine and send the data over to the burner. Dale Frye @ Washington University