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Thread: 486 mainboard

  1. #1
    Join Date
    Nov 2003
    Location
    London, England
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    1,348

    Default 486 mainboard

    I've finally managed to get this awful motherboard sussed out and set up now, I don't think I have ever seen such a complicated design for setting things up! About 1000 different jumpers!

    Anyway, a couple of questions

    1. Turbo Button. My turbo button has 3 wires, but the motherboard only has two pins. It is set up on 2 pins and works - LED comes on when Turbo is engaged, and off when disabled. Benchmarks show the hardware is responding too. There is also a neat display on the case showing the speed (75MHz). Years ago, when I had it with a 33MHz, the display used to change to show the lower speed when turbo was disabled. How can I do this? At the moment there are no wires either from the button, LED or mainboard to the display board (only power), but I would assume there should be to detect the speed change.

    2. This is the mainboard schematic:
    http://www.thegreenhouse.us/th99/m/I-L/33140.php

    J1 and JP13 are labelled as "Green PC Connector". What is a Green PC Connector?

    Umm... that's all for now! Thanks in advance

  2. #2

    Default

    cool, it's got 32-bit vesa slots.

    as for the green pc connector thingy, i've never heard of that before. perhaps its some sort of power saving feature? don't know, sorry.
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  3. #3
    Join Date
    Jul 2003
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    Västerås, Sweden
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    Default

    Green mode is power management, allowing the computer to save power when it is not used. It probably was brand new by the age of the 486, and exists still today (or at least I saw some old Celeron boards that had a specific switch for enabling it). I don't know what the connector is meant to be though; maybe a button to toggle if you want power management mode or not?
    Anders Carlsson

  4. #4
    Join Date
    May 2006
    Location
    Melbourne, Australia
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    6,600

    Default

    Quote Originally Posted by dongfeng
    My turbo button has 3 wires, but the motherboard only has two pins. It is set up on 2 pins and works - LED comes on when Turbo is engaged, and off when disabled.
    Yes, normally only two wires/pins for the 'turbo' functionality. But on some motherboards, shorting the two pins turns ON 'turbo' and and other motherboards, shorting the two pins turns OFF 'turbo'. The three-wire turbo button allows for both types of motherboards.

    Quote Originally Posted by dongfeng
    There is also a neat display on the case showing the speed (75MHz). Years ago, when I had it with a 33MHz, the display used to change to show the lower speed when turbo was disabled. How can I do this? At the moment there are no wires either from the button, LED or mainboard to the display board (only power), but I would assume there should be to detect the speed change.
    The display module requires power, and a signal to cause the display to change. The signal normally comes from the motherboard (because some motherboards will turn off/on turbo when a particular keyboard sequence is used). To control what numbers are displayed on the display module, the module usually has a bunch of jumpers on it.

    It sounds like your machine is similiar to a 386 I have. The case has both a turbo LED and a display module, but the motherboard only has a connector for the LED. In my machine, the signal that controls the display module comes from an extra wire soldered to the turbo switch.

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