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Motherboard Schematic Diagrams - anyone know where you can get these?

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  • Motherboard Schematic Diagrams - anyone know where you can get these?

    Anyone know where I can get motherboard schematic diagrams....mainly to check voltage levels on motherboards...CPU - RAM - PCI, etc.
    EPIC or Shuttle schematics would be wonderful, but any type would help!

  • #2
    Couple motherboards I purchased have had them with them. Otherwise I would say call the customer service for the company that makes the mobo.


    • #3
      I usually try to apply my experience working with boards to check various voltages. With your voltmeter on and ground connected, start probing the regulators. Assuming the motherboard is good, 0V means you're connecting to GND.

      -Probe the "+" end of various capacitors (usually parallel to each other that's why you see a group of them). The other end is usually connected to GND so you should get 0V again. These are filtering caps. This is the easiest way to obtain various voltages from regulators feeding the mobo.

      -Start probing regulators and FETs. You should be getting about 2.5V for DDR memory on average. The regulators and FETs are fat square blocks with a metal tab that's soldered onboard. Most of the regulators have 3 pins, and some have the middle pin chopped off. For example, a 3.3V regulator may be fed from a +5V source. On the 3 pins, you should be seeing 0V, 3.3V (output), and 5V (input). You can probe the tab, and should be 0V (GND). There maybe a voltage monitor IC that monitors all of the voltage planes. It'll send a reset signal if there is a problem.

      -The CPU should get it's regulation feed from a +12V or +5V source. If it's a mobo with a 4pin connector included, then it definitely gets a +12V source feeding its adjustable regulator. Look at the specs of your CPU to determine what voltage it should be running at.