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Question about my 5V Rail and other stuff.

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  • Question about my 5V Rail and other stuff.

    This isn't directly related to my carputer, but I thought it'd be a good place to ask.

    My mobo monitoring software is reporting that my 5-V rail is only spitting out about 4.6V. All my other rails are running at or extremely close to their stated voltage. Is this significant enough to worry about? What devices are powered by my 5V rail? I'm thinking I maybe I have too much crap on it or something.

    Also, I have basic knowledge of circuits and electronics, but how do I apply that to an ATX design (if I put a molex connector here, does it make it a series circuit or a parallel circuit?). I'm guessing that most everything in our PC's are in series. However, what happens when I put a y-splitter on a molex connector to say... put another fan on the PC? Theoretically, what determines how many devices I can put in my computer?

    I've got a 430W Antec Truepower.
    2006 Rav4 + iPod, still CarPCless

  • #2
    All power in a pc is connected parallel, not serial. If you'd do serial, and disconnected one component, none would receive power anymore... Also, how can you garantee 12 or 5 V in a serial scheme, when resistances change or are unknown...

    When adding a Y splitter, you just add another parallel connection.

    About the 5v, I don't know the margins on that one, but if your pc runs fine, don't worry about it.
    List of front-ends/usefull apps
    XTroniC | XTroniC Direct


    • #3
      I concur. If it isn't broke, don't fix it If the pc doesn't give you any trouble, doesn't lock up a lot, then 4.6 volts isn't a problem.

      14" LCD, EPIA MII-10000, 256MB, Wireless LAN, GPS, CDRW/DVD, ELM Scan,
      200wRMS inverter (for the screen), CarPC Pro v2.4 Power Controller,
      2 12" Pioneer Premiers, Sony 6x9s, Sony Xplode Class D mono block, Pheonix Gold A/B amp for highs


      • #4
        If you want to know what your 5V rail is at, then use a meter. The monitoring chips can be anywhere from accurate to completely unreliable for this. The minimum and maximum values on each rail are defined in the ATX standard.
        2004 4runner


        • #5
          Anybody point me to a website with some information on basic ATX concepts? With every Molex connector, there's a 12V, two grounds, and a 5V, right? What does the 3V rail do? Also, I noticed that my hard drive takes both a 12V and a 5V input.

          I've heard other people using the computer's PS to power other 12V devices in their car such as a display or cold cathode lights. Do you just splice out a molex connector, take the 12V and attach the ground? Which ground do you use?

          What's the math involved when figuring out if you're overloading your PS? Is it based on current or wattage?
          2006 Rav4 + iPod, still CarPCless


          • #6
   might be a good place for you to start with atx concepts



            • #7
              Thanks, that helped a little bit. Still a bit unsure as to what the different rails do.
              2006 Rav4 + iPod, still CarPCless