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ATX power supply to bench supply conversion

Discussion in 'Electronic Repair' started by Kingcosmos, Apr 2, 2007.

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  1. Kingcosmos

    Kingcosmos Guest


    Not sure if this is the best group for this. I found several articles
    on the process of using an ATX power supply and convert it to a bench
    supply. The problem I am having is that the wire color codes and pin
    outs are not standard ATX. I looked several places, including this
    website, to see if I could find out what the pin outs would be.

    It is a LiteOn 140W PSU with +/-5V, +/-12V, +18V, and +5V standby
    (underside of the PSU). I actually had to open it to see what wires
    were what voltage. The board actually has them listed as:

    6 Red: +5V
    5 Black: Ground
    1 White: +18V
    1 Yellow: -12V
    1 Purple: -5V
    1 Grey: PG, I am guessing 'Power Good'
    1 Orange: +12V
    2 Brown: P/C and F/C (not sure what these are supposed to be)

    The pinouts from 1 to 20 are:


    Any ideas? I am out of them. Thanks in advance.
  2. Lionel

    Lionel Guest

    Um. What's your actual question? Your colour coding looks correct at a
    glance, so you know which voltages should be on which wires. As you
    guessed, PG = "power good", so all you need to do it short the grey
    wire to a black wire (you can use a 1K resistor if you're feeling
    paranoid), & the it'll power up just fine. I have a couple of PC PSUs
    set up the same way on my own bench.
  3. Kingcosmos

    Kingcosmos Guest

    I guess it is ok; however, every single site I go to does not show
    this pin out or color coding for an ATX power supply. Real quick,
    Blue is -12V on every site that I have seen...among others.

    The question I really wanted to ask concerned the brown wires. Not
    sure what they are supposed to be. The board says P/C and F/C. If
    shorting the grey wire to ground is all I need to do, I will set that
    up and just measure them with a Fluke.
  4. Franc Zabkar

    Franc Zabkar Guest

    +18V is not a standard ATX voltage. Furthermore, the LiteOn has no
    +3.3V rail. Could this supply be for an industrial PC ???
    Power/Control ??? Fan/Control ???

    - Franc Zabkar
  5. Meat Plow

    Meat Plow Guest

    A 140 watt supply in an industrial PC? :)
    Maybe it's out of an Apple?

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  6. Lionel

    Lionel Guest

    That's what I'd do.
  7. Kingcosmos

    Kingcosmos Guest


    The grey wire appears to be power good so that should be an output. I
    connected the only +5V coming up (which I think is the standby
    voltage) to the brown wire P/C (I agree-- power control), and the rest
    of the rails came up.

    Everything looks good. Still not sure about what the supply actually
  8. Franc Zabkar

    Franc Zabkar Guest

    In a regular ATX PSU, the PS_ON pin is shorted to ground to turn on
    the supply.
    Could the 1-wire 18V rail be for an LCD panel or touch screen ???
    Point of Sale system ???

    - Franc Zabkar
  9. JW

    JW Guest

    Sure! We ship industrial nema-4 systems with even less power. 50-80 watt
    power supplies and mobile processors.
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