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Thread: I got an Olivetti M300-25 (P500/E)

  1. #1
    Join Date
    Feb 2015
    Location
    Québec, Canada
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    258

    Default I got an Olivetti M300-25 (P500/E)

    I bought this Olivetti P500/E from Italy. The P500/E is "more commonly" known as the M300-25. "More commonly known" as in no one has ever heard of both of them, but on the chance that they have, they'll know about the M300-25 before the P500/E... I also don't remember seeing "P500/E" in anything, the computer is always referred to as the M300-25. I have never found out why the P500/E exists, or if there are supposed to be any differences between it and the M300-25. It is a 386SX Microchannel PC from 1991 or 1992.

    Let's talk about the name P500/E. P500 was the name of Olivetti's first Microchannel system, a 386SX desktop PC released in 1989. When Olivetti added the letter "E" to a computer's name it usually indicated that it was a new, superior version. So is the P500/E a newer, superior version of the P500? Well it's smaller so it's less expandable, and they both support up to 16MB of memory. The P500 uses the Intel 82310 chipset while the P500/E uses the 82311. The P500 has a 16MHz clock, the P500/E has a 20MHz clock. If you consider it an improvement then the name will make sense to you... A theory of mine is that the name P500/E was later changed to M300-25, or maybe it was the opposite, or maybe something else... And what does M300-25 mean? M300 means that it is a 386SX computer, the hyphen means that it is part of the M300-xx series of computers, and the 25 possibly does not mean anything. Confusingly, some later M300-xx models were 486-based instead.

    Another strange thing about this computer. It uses the first version of the XP 2655 chassis, but has the newer "black" logo and name badge, instead of the blue and purple "ladder" LaNB more commonly associated with this chassis. This is very rare. The M300-25 (P500/E) is easily identifiable. It is possibly the only PC with this chassis to have a black LaNB + no front control panel (console). The rear is also unique to it. Because of the Microchannel riser card, it only has 3 expansion slots, and they have thumbscrews to fit in the whole MCA spiel. The computer uses those strange DBA (Direct Bus Attachment) hard drives.

    Under the disk drive is something I have never seen before? It's a metal box on a tray, it has to be factory. The disk drive data cable from the motherboard enters it, and another data cable comes out of it to hook up your drives. The box takes 5 volts from the power supply, and a lock comes out of it. My guess is that if you have the key, you can lock the disk drives that are in the system, preventing someone from using them? I haven't taken it apart to avoid breaking it.

    Photos
    https://image.ibb.co/mxqByp/DSC06763-min.jpg - Front

    https://image.ibb.co/gT0YB9/DSC06747-min.jpg - Back

    https://image.ibb.co/iOzh4U/DSC06740-min.jpg - DBA

    https://image.ibb.co/jyYydp/DSC06764-min.jpg - Metal box

    https://image.ibb.co/bDCfr9/DSC06732-min.jpg - Motherboard. As you can see the DS1287 was hacked. Sadly don't ask me to dump the programmable circuits I don't know how to read them and they are soldered anyway. Of course that includes the 8742. The BIOS EPROM is socketed but it is a type I have never seen before, D27C010. I don't think I can read that one. Above the CPU is a custom gate array.
    "QFP132 - Gate array implementing
    ASIC ADB Addressing Buffers and data
    Buffers
    - Implements swapping function
    between 16 and 8 bits"

    https://image.ibb.co/cGhfr9/DSC06742-min.jpg - It came with a keyboard and a mouse. The keyboard is the good old ANK 27, the mouse is an M-S28. This is the first time I see an Olivetti mouse, I think it's simply a rebadged Logitech. The monitor is an old monochrome one I was lucky enough to find locally believe it or not. Pretty cool huh?

    I have another Microchannel Olivetti, an M6 500 suprema, but it's just the board, nothing else. Anyway, I'm most definitely the only person on this forum to have two Olivetti MCA systems, and no IBM ones hahaha.
    • The only computer from my childhood that I'm missing is an Olivetti M380-40... Please help me find a solution to this problem
    • Looking for pictures of the following Olivetti computers: M380 W, M380 XP4, M400-60, M480... Complete list: http://pastebin.ca/3629976

  2. #2

    Default

    Very nice! Olivetti has more documentation than obscure Philips/Magnavox/Vendex boxes probably.

  3. #3
    Join Date
    Oct 2014
    Location
    near frankfurt/m, germany
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    741

    Default

    M300 series machines are ISA only, like allmost all early M-Series (Exception: M486 which is EISA desktop machine based on LSX-5010/20). P-Series is Microchannel. Maybe P500, P500/E (Enhanced) uses same chassis as M300-25. M-Series later also was used for some PCIbased machines, but there the naming schema again was changed, not anymore so strict like M plus 2-3 digits number, like M4 Modulo series, M24-II, ...

  4. #4
    Join Date
    Oct 2014
    Location
    near frankfurt/m, germany
    Posts
    741

    Default

    Quote Originally Posted by PeterNC View Post
    Very nice! Olivetti has more documentation than obscure Philips/Magnavox/Vendex boxes probably.
    Unfortunatelly not. Long time ago there was a server at olivetti.it, where you could download anything for any machine, drivers, os, customer test, diagnostics, ... Unfortunatelly not available anymore and nobody seems to have a backup.

  5. #5
    Join Date
    Feb 2015
    Location
    Québec, Canada
    Posts
    258

    Default

    M300-25 is MCA, look at cap23.pdf. The P500/E is simply an M300-25 with a strange name. There's also the M480-30, it's a P750 with a different name. And then there are the very weird M6 500 suprema PCs, those were the last MCA systems Olivetti made.
    • The only computer from my childhood that I'm missing is an Olivetti M380-40... Please help me find a solution to this problem
    • Looking for pictures of the following Olivetti computers: M380 W, M380 XP4, M400-60, M480... Complete list: http://pastebin.ca/3629976

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