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Thread: DSATX power question, un-needed wire on 20 pin?

  1. #1
    FLAC greatwhite's Avatar
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    DSATX power question, un-needed wire on 20 pin?

    question for those in the know abut power supplies:

    My dsatx has the standard AtX 20 pin connector. My mother board does also, and all the color codes match, except for a white wire on pin 18 (-5v). The dsatx has the white wire but my motherboard does not (It's a dell, and yes, the ps is atx)

    The motherboard has a pin at 18 but as mentioned, there is no white wire from the original PS.

    Should I just remove the white wire to match my motherboards configuration? (that's what I'm thinking)

    Thanks for any help.
    For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return.
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  2. #2
    FLAC greatwhite's Avatar
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    Found this onthe forum:

    WHITE: -5v (Used only by legacy ISA add-on cards. May be removed.)

    ATX Pinout Configuration

    Any truth to this? If so, I can just remove the white, correct?

    Cheers
    For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return.
    Leonardo Da Vinci

  3. #3
    FLAC greatwhite's Avatar
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    Hmm...........

    More info

    http://www.pcguide.com/ref/power/sup...erboard-c.html

    Seems my motherboard complies with what they are calling SFX (no -5v and low power) even though it's a full atx (p4, the newer P4's don't have the white wire either if I understand correctly).

    And here's a litle more info on that:

    http://www.pcguide.com/ref/power/sup/form_SFX.htm

    Here's an exerpt:
    In many ways the SFX form factor could be considered a "little brother" to ATX. It is mostly interchangeable with the ATX power supply. The main SFX motherboard connector is 20 pins, in the same shape and size as the ATX connector, and 19 of the pins are the same as those of ATX. The one difference here is that the SFX power supply specification does not call for providing the -5 V compatibility voltage. The reason is that -5 V is only required for ISA bus compatibility, and since Intel wants to move new systems away from ISA (to PCI and AGP only) it intentionally left -5 V off the specification (presumably to save on the cost of the power supply). Systems that need -5 V and want to use the SFX power supply must generate it on the motherboard. The SFX power supply specification calls for the power supply fan to be internally thermally speed-controlled, but an additional "Fan On/Off" signal is included on the SFX optional motherboard connector. Another issue with ATX exchangeability is that an SFX power supply equipped only with the standard 60 mm fan may have considerable trouble cooling a large ATX system case.

    more:
    -5 V: A now archaic voltage, -5 V was used on some of the earliest PCs for floppy controllers and other circuits used by ISA bus cards. It is usually provided, in small quantity (generally less than 1A), for compatibility with older hardware. Some form factor power supplies such as the SFX no longer bother to supply it (systems using the SFX power supply are intended not to have ISA bus slots).




    Sorry if this is "old hat" to some of you. It's new info to me and may help out someone else in a similar predicament......

    Cheers
    For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return.
    Leonardo Da Vinci

  4. #4
    Variable Bitrate
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    The Audigy's require a -5v rail. I don't know if that carries over to the X-Fi's. Dell had an annoying habit of offering proprietary motherboard/supplies. Some even used the standard ATX plug, but a different power scheme that would kill the board if you plugged in an ATX PSU!
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    FLAC greatwhite's Avatar
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    Checked it out already. The optiplex gx 270 is atx, just doesn't have the -5v (white wire).

    Apparently, -5v is from the ISA days (IBM first out with it) and the newer intel boards make it "on board" for legacy items rather than a dedicated line from the supply. Consequently, it's been dropped by some suppliers. At least that's what I've read. Still kinda new and learning about PS's.

    Thanks for the info though.
    For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return.
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  6. #6
    FLAC is for flaccid parksgm's Avatar
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    Quote Originally Posted by greatwhite View Post
    Checked it out already. The optiplex gx 270 is atx, just doesn't have the -5v (white wire).

    Apparently, -5v is from the ISA days (IBM first out with it) and the newer intel boards make it "on board" for legacy items rather than a dedicated line from the supply. Consequently, it's been dropped by some suppliers. At least that's what I've read. Still kinda new and learning about PS's.

    Thanks for the info though.
    I'm using a DS-ATX with a 2.4ghz P4 in a Dell 240, and the DS-ATX is also supplying my screen, a slim DVD/CDRW drive, and about 10 usb peripherals...no complaints or issues in the 6 months I've been running it that way. From my experience, the DS-ATX a great power supply...good luck with your project.

  7. #7
    FLAC greatwhite's Avatar
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    Quote Originally Posted by parksgm View Post
    I'm using a DS-ATX with a 2.4ghz P4 in a Dell 240, and the DS-ATX is also supplying my screen, a slim DVD/CDRW drive, and about 10 usb peripherals...no complaints or issues in the 6 months I've been running it that way. From my experience, the DS-ATX a great power supply...good luck with your project.
    Thanks. I went with the DSATX since my gx270 id a 2.26 (power hungry) P4. I've got a powered hub up front for the slot load dvd/cd and usb's. But it's nice to know the dsatx can handle it.

    Figured I'd go a little overkill and get the dsatx to make sure I wouldn't have power issues. I'm hopng I'll get a nice long stable life out of it too as it's not running close to capacity as a lesser ps would.

    Understressed = good.

    Cheers
    For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return.
    Leonardo Da Vinci

  8. #8
    FLAC greatwhite's Avatar
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    Yippee! Small success and progress.

    I jumpered the dsatx in to dumb mode, hooked up the connections, said a prayer or two for my motherboard, hit the power button and the carputer is up and everything works great!

    Probably a minor thing to most, but it's progress for me.

    Next up:

    Using the more advanced (well, the basic startup and shutdown stuff as well as the anti thump feature) features in the dsatx and then learning the "brainstem".

    I'm so happy it's moving forward!

    Quick question for those who have gone from inverter to dc-dc:
    Do you notice a difference in running time before the battery goes low? It would be nice to be able to take the car to drive in movies again (they transmit the sound on FM for the movie around here).

    Cheers
    For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return.
    Leonardo Da Vinci

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